ML042950366

Semi-Annual Groundwater Monitoring Report March and June 2004 Quarterly Sampling Events

ML042950366
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	10/05/2004
From:	Connecticut Yankee Atomic Power Co
To:	NRC/FSME
References
-RFPFR, CY-04-191, FOIA/PA-2005-0203
Download: ML042950366 (117)

Text

Connecticut Yankee Atomic Power Company Haddam Neck Plant 362 Injun Hollow Road East Hampton, CT 06424-3099 Semi-Annual Groundwater Monitoring Report March and June 2004 Quarterly Sampling Events Prepared by Connecticut Yankee Atomic Power Company October 5, 2004

Connecticut Yankee Atomic Power Company Haddam Neck Plant 362 Injun Hollow Road East Hampton, CT 06424-3099 Semi-Annual Groundwater Monitoring Report March and June 2004 Quarterly Sampling Events Prepared by Connecticut Yankee Atomic Power Company October 5, 2004

Table of Contents Section..................................................

Page 1

Introduction..................................................

1 1.1 Groundwater Monitoring Program Overview...................................................

1 1.2 Groundwater Monitbring Program Plans and Procedures.................................. 2 2

Groundwater Flow and Direction.....................................

3 2.1 Background..........................................

3 2.2 March 2004 Groundwater Elevation Data...................................

4 2.2.1 March 2004 Hydrographs........................................

6 2.2.2 March 2004 Groundwater Flow Maps......................................

.8 2.2.3 June 2004 Hydrographs 10 2.2.4 June 2004 Groundwater Flow Maps

.................................... 11 3

Groundwater Sampling and Analysis.........

14 3.1 Field Measurements..........................................

14 3.2 Summary of Field Measurements

......................... 15 3.3 Routine Lab Analyses and Locations

........................ 15 3.4 Special HTD Lab Analyses and Locations 17 4

Laboratory Analytical Results

........................... 18 4.1 Boron 18 4.2 Gross Alpha 19 4.3 Gross Beta 19 4.4 Tritium Results

.20 4.5 Co-60................

20 4.6 Cs-137 20 4.7 Alpha Isotopic Results 21 4.8 Sr-90 Results 21 5

Data Quality Assessment..

23 5.1 Data Quality Metrics 23 5.1.1 Precision 23 5.1.2 Accuracy 23 5.1.3 Completeness 24 5.1.4 Comparability 24 5.1.5 Analytical Bias Assessment 24 5.1.6 Laboratory Audits/Assessments/Oversight Activitiesvs..

24 5.1.7 Issue Resolution/Case Narrative 24 5.2 Data Quality Results.....................

24 5.2.1 Precision........................

25 5.2.2 Accuracy 26 5.2.3 Completeness 29 5.2.4 Comparability 29 5.2.5 Issue Resolution/Case Narrative 31 5.2.6 Representativeness 33 5.2.7 Lab Audits 35 5.2.8 Analytical Bias Assessment 35 5.3 Data Quality Summary 42 6

Spatial and Trend Analysis.

44 6.1 Spatial Distribution of SOCs

........................ 44 6.1.1 Spatial Distribution of SOCs from March 2004 Groundwater Sampling44

Table of Contents Section...................................

Page 6.1.2 Spatial Distribution of SOCs from June 2004 Groundwater Sampling 47 6.2 Trend Analysis of SOCs.50 6.2.1 Boron Trend Analysis

................ 50 6.2.2 Gross Alpha Trend Analysis 51 6.2.3 Gross Beta 51 6.2.4 Tritium Trend Analysis 52 6.2.5 Strontium-90 Trend Analysis 53 6.2.6 Cesium-137 Trend Analysis 54 6.2.7 Alpha Isotopic Analyses 54 6.3 Linear Regression Analysis 54 6.3.1 Sr/Y-90 + Cs-137 vs Gross Beta

.54 7 Conclusions and Recommendations 55 7.1 Groundwater Quality Status 55 7.2 Recommendations for Subsequent Groundwater Monitoring Sampling Events55 8

References 57 9

Definitions

.59 10 Acronvms

.61 11

List of Tables NIurm ber......................................................

Page Table 2-1: Summary of Monitoring Well Information..................................................... 63 Table 2-2: Selected Events in Operation of the Water Level M6nitoring System at HNP

................................... 65 Table 2-3: Summary of Groundwater Elevation Conditions Observed in the Unconsolidated Hydrostratigraphic Unit During the First Quarter 2004................. 66 Table 2-4: Summary of Groundwater Elevation Conditions Observed in the Shallow Bedrock Hydrostratigraphic Unit During the First Quarter 2004............................. 67 Table 2-5: Summary of Groundwater Elevation Conditions Observed in the Deep Bedrock Hydrostratigraphic Unit During the First Quarter 2004............................. 68 Table 2-6: Summary of Static Water Levels in Monitoring Wells for March and June 2004 Used to Complete Groundwater Flow Maps................................................... 69 Table 2-7: Summary of Groundwater Elevation Conditions Observed in the Unconsolidated Hydrostratigraphic Unit During the Second Quarter 2004............. 70 Table 2-8: Summary of Groundwater Elevation Conditions Observed in the Shallow Bedrock Hydrostratigraphic Unit During the Second Quarter 2004........................ 71 Table 2-9: Summary of Groundwater Elevation Conditions Observed in the Deep Bedrock Hydrostratigraphic Unit During the Second Quarter 2004........................ 72 Table 3-1: Summary of Field Parameters for March 2004............................................... 73 Table 3-2: Summary of Field Parameters for June 2004.................................................. 74 Table 4-1: Boron Concentrations (jGIL) in Groundwater............................................... 76 Table 4-2: Gross a, fl, Sr-90 and Cs-137 Concentrations (pCi/L) in Groundwater.......... 78 Table 4-3: Tritium Concentrations (pCi/L) in Groundwater............................................ 87 Table 4-4: Hard-to-Detect (HTD) Concentrations (pCi/L) in Groundwater.................... 89 Table 5-1: Required MDC Values............................................................

98 Table 5-2: Field Duplicate Results for March 2004......................................................... 98 Table 5-3: Field Duplicate Results for June 2004............................................................ 98 Table 5-4: Lab Duplicate Results for March 2004........................................................... 99 Table 5-5: Lab Duplicate Results for June 2004............................................................

99 Table 5-6: DOE QAP Lab Performance Data Summary................................................ 100 Table 5-7: MAPEP Lab Performance Data Summary.................................................... 100 Table 5-8: ERA Lab Performance Data Summary for Water (ERA 52 - 55, 57)........... 100 Table 5-9: QC Summary for March 2004 Sample Event................................................ 101 Table 5-10: QC Summary for June 2004 Sample Event................................................. 101 Table 5-11: Lab QC Acceptance Limits.......................................................

101 Table 5-12: Internal Performance Data Summary (LCS, MS)........................................ 101 Table 5-13: Summary Statistics for March 2004.......................................................

102 Table 5-14: Summary Statistics for June 2004.......................................................

103 Table 5-15: Limiting Mean Distribution Summary for March 2004.............................. 104 Table 5-16: Limiting Mean Distribution Summary for June 2004................................. 105 Table 5-17: Observed False-Positive Rates............................................ 106 Table 5-18: Data Quality Metrics............................................

106

.M

List of Figures Number...............................

Page Figure 1-1: Haddam Neck Plant Property Map................................

107 Figure 2-1: Groundwater and Surface Water Monitoring Locations at the EOF and Parking Lot Area of the Haddam Neck Plant, Haddam Neck, CT............

............. 108 Figure 2-2: Groundwater and Surface Water Monitoring Locations at the Industrial Area and Upper Peninsula Area of the Haddam Neck Plant, Haddam Neck, CT........... 109 Figure 2-3: Groundwater Monitoring Locations at the Peninsula Area of the Haddam Neck Plant, Haddam Neck, CT...........................................................

110 Figure 2-4: Groundwater Elevation, Inferred Contours and Flow Direction in the Unconsolidated Material of the Connecticut Yankee Haddam Neck Plant February 12,2004 4:35 High Tide Haddam Neck, CT.......................................................... 111 Figure 2-5: Groundwater Elevation, Inferred Contours and Flow Direction in the Unconsolidated Deposits of the Connecticut Yankee Haddam Neck Plant February 12, 2004 11:35 Low Tide Haddam Neck, CT.................................................

112 Figure 2-6

Groundwater Elevation, Inferred Contours and Flow Direction in the Shallow Bedrock of the Connecticut Yankee Haddam Neck Plant February 12, 2004 4:35 High Tide Haddam Neck, CT................................................. 113 Figure 2-7: Groundwater Elevation, Inferred Contours and Flow Direction in the Shallow Bedrock of the Connecticut Yankee Haddam Neck Plant February 12, 2004 11:35 Low Tide Haddam Neck, CT.................................................

114 Figure 2-8: Groundwater Elevation, Inferred Contours and Flow Direction in the Deep Bedrock of the Connecticut Yankee Haddam Neck Plant February 12, 2004 4:35 High Tide Haddam Neck, CT Figure 2-9: Groundwater Elevation, Inferred Contours and Flow Direction in the Deep Bedrock of the Connecticut Yankee Haddam Neck Plant February 12, 2004 11:35 Low Tide Haddam Neck, CT................................ 115 Figure 2-9: Groundwater Elevation, Inferred Contours and Flow Direction in the Deep Bedrock of the Connecticut Yankee Haddam Neck Plant February 12,2004 11:35 Low Tide Haddam Neck, CT.................................................

116 Figure 2-10: Groundwater Elevation, Inferred Contours and Flow Direction in the Unconsolidated Deposits of the Connecticut Yankee Haddam Neck Plant June 12, 2004 21:00 High Tide Haddam Neck, CT.................................................

117 Figure 2-11: Groundwater Elevation, Inferred Contours and Flow Direction in the Unconsolidated Deposits of the Connecticut Yankee Haddam Neck Plant June 12, 2004 15:10 Low Tide Haddam Neck, CT.................................................

118 Figure 2-12: Groundwater Elevation, Inferred Contours and Flow Direction in the Shallow Bedrock of the Connecticut Yankee Haddam Neck Plant June 12, 2004 21:00 High Tide Haddam Neck, CT.................................................

119 Figure 2-13: Groundwater Elevation, Inferred Contours and Flow Direction in the Shallow Bedrock of the Connecticut Yankee Haddam Neck Plant June 12, 2004 15:10 Low Tide Haddam Neck, CT Figure 2-14: Groundwater Elevation, Inferred Contours and Flow Direction in the Deep Bedrock of the Connecticut Yankee Haddam Neck Plant June 12,2004 21:00 High Tide Haddam Neck, CT.............. 120 Figure 2-14: Groundwater Elevation, Inferred Contours and Flow Direction in the Deep Bedrock of the Connecticut Yankee Haddam Neck Plant June 12, 2004 21:00 High Tide Haddam Neck, CT...............

121

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List of Figures Number.......................................................

Page Figure 2-15: Groundwater Elevation, Inferred Contours and Flow Direction in the Deep Bedrock of the Connecticut Yankee Haddam Neck Plant June 12, 2004 15:10 Low Tide Haddam Neck, CT........................................................

122 Figure 5-1: Mn-54 Rank Order for March 2004.......................................................

124 Figure 5-2: Mn-54 Normality Plot for March 2004....................................................... 124 Figure 5-3: Cs-137 Rank Order for March 2004.......................................................

125 Figure 5-4: Cs-137 Normality Plot for March 2004....................................................... 125 Figure 5-5: Co-60 Rank Order for June 2004.......................................................

126 Figure 5-6: Co-60 Normality Plot for June 2004.......................................................

126 Figure 5-7: C-14 Rank Order for March 2004.......................................................

127 Figure 5-8: C-14 Normality Plot for March 2004....................................

127 Figure 5-9: Fe-55 Rank Order for June 2004....................................

128 Figure 5-10: Fe-55 Normality Plot for June 2004....................................

128 Figure 5-1 1: Sr-90 Rank Order for June 2004....................................

129 Figure 5-12: Sr-90 Normality Plot for June 2004....................................

129 Figure 5-13: Cm-242 Rank Order for March 2004....................................

130 Figure 5-14: Cm-242 Normality Plot for March 2004....................................

130 Figure 5-15: Am-241 Rank Order for March 2004....................................

131 Figure 5-16: Am-241 Normality Plot for March 2004...................

................. 131 Figure 6-1: Distribution of Selected Substances of Concerns in Monitoring Wells at the Industrial Area and Upper Peninsula Area of the Haddam Neck Plant March 2004, Haddam Neck, CT...........

132 Figure 6-2: Distribution of Selected Substances of Concern in Monitoring Wells at the Peninsula of the Haddam Neck Plant March 2004, Haddam Neck Plant, Haddam Neck, CT....

133 Figure 6-3: Inferred Distribution of Unfiltered Boron ([tg/L) in the Unconsolidated Deposits Hydrostratigraphic Unit at the Industrial Area and the Upper Peninsula Area of the Haddam Neck Plant March 2004, Haddam Neck, CT......................... 134 Figure 6-4: Inferred Distribution of Unfiltered Boron ([tg/L) in the Shallow Bedrock Hydro-stratigraphic Unit at the Industrial Area and the Upper Peninsula Area of the Haddam Neck Plant March 2004, Haddam Neck, CT....................

... 135.

Figure 6-5: Inferred Distribution of Unfiltered Boron (pg/L) in the Deep Bedrock Hydrostratigraphic Unit at the Industrial Area and the Upper Peninsula Area of the Haddam Neck Plant March 2004, Haddam Neck, CT............................................ 136 Figure 6-6: Inferred Distribution of Unfiltered Tritium Activity Concentrations (pCi/L) in the Unconsolidated Deposits Hydrostratigraphic Unit at the Industrial Area and the Upper Peninsula Area of the Haddam Neck Plant March 2004, Haddam Neck, CT 137 Figure 6-7: Inferred Distribution of Unfiltered Tritium Activity Concentrations (pCi/L) in the Shallow Bedrock Deposits Hydrostratigraphic Unit at the Industrial Area and the Upper Peninsula Area of the Haddam Neck Plant March 2004, Haddam Neck, CT 1.....................................

138 Figure 6-8: Inferred Distribution of Unfiltered Tritium Concentrations (pCi/L) in the Deep Bedrock Hydrostratigraphic Unit at the Industrial Area and the Upper Peninsula Area of the Haddam Neck Plant March 2004, Haddam Neck, CT........ 139

List of Figures Number........................................................

Page Figure 6-9: Inferred Distribution of Unfiltered Strontium-90 Activity Concentrations (pCi/L) in the Unconsolidated Deposits Hydrostratigraphic Unit at the Industrial Area and the Upper Peninsula Area of the Haddam Neck Plant March 2004, Haddam Neck, CT....................................................

140 Figure 6-10: Inferred Distribution of Unfiltered Strontium-90 Activity Concentrations (pCi/L) in the Shallow Bedrock Hydrostratigraphic Unit at the Industrial Area and the Upper Peninsula Area of the Haddam Neck Plant March 2004, Haddam Neck, CT....................................................

141 Figure 6-11: Inferred Distribution of Unfiltered Strontium-90 Activity Concentrations (pCi/L) in the Deep Bedrock Hydrostratigraphic Unit at the Industrial Area and the Upper Peninsula Area of the Haddam Neck Plant March 2004, Haddam Neck, CT 142 Figure 6-12: Distribution of Selected Substances of Concerns in Monitoring Wells at the Industrial Area and Upper Peninsula Area of the Haddam Neck Plant June 2004, Haddarn Neck, CT...........

143 Figure 6-13: Distribution of Selected Substances of Concerns in Monitoring Wells at the Peninsula Area of the Haddam Neck Plant June 2004, Haddam Neck, CT............ 144 Figure 6-14: Distribution of Selected Substances of Concerns in Monitoring Wells at the EOF and Parking Lot Area of the Haddam Neck Plant March and June 2004, Haddam Neck, CT...........................................................

145 Figure 6-15: Inferred Distribution of Unfiltered Boron (gg/L) in the Unconsolidated Deposits Hydrostratigraphic Unit at the Industrial Area and the Upper Peninsula Area of the Haddam Neck Plant June 2004, Haddam Neck, CT............................ 146 Figure 6-16: Inferred Distribution of Unfiltered Boron ([tg/L) in the Shallow Bedrock Hydro-stratigraphic Unit at the Industrial Area and the Upper Peninsula Area of the Haddam Neck Plant June 2004, Haddam Neck, CT............................................... 147 Figure 6-17: Inferred Distribution of Unfiltered Boron ([tg/L) in the Deep Bedrock Hydro-stratigraphic Unit at the Industrial Area and the Upper Peninsula Area of the Haddam Neck Plant June 2004, Haddam Neck, CT............................................... 148 Figure 6-18: Inferred Distribution of Unfiltered Tritum Activity Concentrations (pCi/L) in the Unconsolidated Deposits Hydrostratigraphic Unit at the Industrial Area and the Upper Peninsula Area of the Haddam Neck Plant June 2004, Haddam Neck, CT

~~~~~~.................................................................................................................................

149 Figure 6-19: Inferred Distribution of Unfiltered Tritium Activity Concentrations (pCi/L) in the Shallow Bedrock Hydrostratigraphic Unit at the Industrial Area and the Upper Peninsula Area of the Haddam Neck Plant June 2004, Haddam Neck, CT........... 150 Figure 6-20: Inferred Distribution of Unfiltered Tritium Activity Concentrations (pCi/L) in the Deep Bedrock Hydrostratigraphic Unit at the Industrial Area and the Upper Peninsula Area of the Haddam Neck Plant June 2004, Haddam Neck, CT...........

151 Figure 6-21: Inferred Distribution of Unfiltered Strontium-90 Activity Concentrations (pCi/L) in the Unconsolidated Deposits Hydrostratigraphic Unit at the Industrial Area and the Upper Peninsula Area of the Haddam Neck Plant June 2004, Haddam Neck, CT....

152 Figure 6-22: Inferred Distribution of Unfiltered Strontium-90 Activity Concentrations (pCi/L) in the Shallow Bedrock Hydrostratigraphic Unit at the Industrial Area and

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List of Figures Number....

Page the Upper Peninsula Area of the Haddam Neck Plant March 2004, Haddam Neck, CT.

153 Figure 6-23: Inferred Distribution of Unfiltered Strontium-90 Activity Concentrations (pCi/L) in the Deep Bedrock Hydrostratigraphic Unit at the Industrial Area and the Upper Peninsula Area of the Haddamn Neck Plant June 2004, Haddam Neck, CT 154 Figure 6-24: Boron Site-wide Concentration Box Plot................................................... 155 Figure 6-25: Box Plot of Gross Alpha Concentrations in Unconsolidated Deposits...... 155 Figure 6-26: Box Plot of Gross Alpha Concentrations in Shallow Bedrock.................. 156 Figure 6-27: Box Plot of Gross Alpha Concentrations in Deep Bedrock....................... 156 Figure 6-28: Gross Alpha Site-wide Concentration Box Plot....................................... 157 Figure 6-29: Box Plot of Gross Beta Concentrations in Unconsolidated Deposits........ 157 Figure 6-30: Box Plot of Gross Beta Concentrations in Shallow Bedrock..................... 158 Figure 6-3 1: Box Plot of Gross Beta Concentrations in Deep Bedrock......................... 158 Figure 6-32: Gross Beta Site-wide Concentration Box Plot........................................... 159 Figure 6-33: H-3 Concentration Trend at Cluster Well MW-102.................................. 159 Figure 6-34: H-3 Concentration Trend at Cluster Well MW-103.................................. 160 Figure 6-35: H-3 Concentration Trend at Cluster Well MW-1II..................................

1.

160 Figure 6-36: H-3 Concentration Trend at Cluster Well MW-105.................................. 161 Figure 6-37: H-3 Concentration Trend at Well MW-I 14S............................................. 161 Figure 6-38: Box Plot of H-3 Concentrations in Unconsolidated Deposits.................... 162 Figure 6-39: Box Plot of H-3 Concentrations in Shallow Bedrock................................ 162 Figure 640: Box Plot of H-3 Concentrations in.Deep Bedrock..................................... 163 Figure 6-41: H-3 Site-wide Concentration Box Plot...................................................... 163 Figure 642: Sr-90 Concentration Trend at Well MW-105S.......................................... 164 Figure 643: Sr-90 Concentration Trend at Cluster Well MW-106................................ 164 Figure 6-44: Sr-90 Concentration Trend at Cluster Well MW-I 03................................ 165 Figure 6-45: Sr-90 Concentration Trend at Well MW-104S.......................................... 165 Figure 646: Box Plot of Sr-90 Concentrations in Unconsolidated Deposits................. 166 Figure 647: Box Plot of Sr-90 in Unconsolidated Deposits (Expanded View).

166 Figure 648: Box Plot of Sr-90 Concentrations in Shallow Bedrock............................. 167 Figure 6-49: Box Plot of Sr-90 Concentrations in Deep Bedrock.................................. 167 Figure 6-50: Sr-90 Site-wide Concentration Box Plot............................................... ;.168 Figure 6-51: Cs-137 Concentration Trend at Cluster Well MW-103.............................. 168 Figure 6-52: Cs-137 Concentration Trend at Well MW-1 15S....................................... 169 Tigure 6-53: Cs-137 Concentration Trend at Cluster Well MW-102.............................. 169 Figure 6-54:. Box Plot of Cs-137 Concentrations in Unconsolidated Deposits.............. 170 Figure 6-55: Box Plot of Cs-137 Concentrations in Shallow Bedrock........................... 170 Figure 6-56: Box Plot of Cs-137 Concentrations in Deep Bedrock.......... ;.................... 171 Figure 6-57: Box Plot of Am-241 Concentrations in Unconsolidated Deposits............ 171 Figure 6-58: Box Plot of Am-241 Concentration in Shallow Bedrock.......................... 172 Figure 6-59: Box Plot of Am-241 Concentration in Deep Bedrock.................................. 172 Figure 6-60: Sr-90/Y-90 + Cs-137 versus Gross Beta..................................................... 174

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List of Appendices Appendix A Appendix B Appendix C Appendix D Appendix E Appendix F Appendix G Appendix H Procedure 5.3-1 First and Second Quarter Hydrographs Field Parameters Boron and Radiochemical Analytical Data Rank Order Plot for the March and June 2004 Sample Event Boron Time Series Plots Tritium Time Series Plots Sesium-137 and Strontium-90 Time Series Plots

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1 Introduction 1.1 Groundwater Monitoring Program Overview This report presents a compilation of the groundwater analytical results and related field measurements associated with two groundwater-sampling events conducted during March and June 2004 at the Connecticut Yankee Atomic Power Company (CYAPCo)

Haddam Neck Plant (HNP) located in Haddam Neck, Connecticut (CT). These groundwater-sampling events were performed in compliance with the quarterly groundwater monitoring program Quality Assurance Project Plan (GMP QAPP 2004) and to provide characterization data input to the CY License Termination Plan (LP 2002).

The objective of this monitoring report is to provide a summary and evaluation of the groundwater analytical results and groundwater elevation data to develop an understanding of plume status concerning substances of concern (SOCs) at the HNP. A focused list of individual radioactive and non-radioactive constituents has been identified as SOCs contributing most of the groundwater contamination at the site. The radiological SOCs at HNP have been identified as tritium, Cs-137, Co-60, and Sr-90, all predictable byproducts of the nuclear fission reaction that was the heat source for this nuclear power generating plant. Boron, the only non-radioactive SOC identified at the facility, was used as a neutron absorber in the primary cooling water, and when detected in environmental samples at HNP is used as an indication of plant-related contamination and also as an effective tracer of potentially-contaminated groundwater.

In order to assess general site groundwater geochemistry and potential contaminant migration mechanism(s), supplemental analyses were collected during the June 2004 event. An integral component of this data summary and evaluation is a discussion of quality-related activities performed to support validation of data collected during these two sampling events.

The primary scope of the Groundwater Monitoring Program (GWMP) is to assess groundwater conditions in the industrial area, the site of former plant operations and probable source areas, and the upper peninsula area, which is adjacent to the industrial area, by conducting quarterly sampling events. These two areas comprise the area where SOCs have been historically been detected and where migration pathways are likely, resulting in the greater number of wells in the monitoring network. One well in both the' Emergency OperationsFacility (EOF) and the lower peninsula area are sampled and analyzed to provide control for monitoring groundwater conditions at the boundaries of the plant property. An overview of the HNP property and the various area designations is provided in Figure 1-1.

1

1.2 Groundwater Monitoring Program Plans and Procedures The March and June 2004 quarterly GWMP sampling and analysis was conducted following specific guidance under applicable CY procedures. The framework for the GWMP is outlined as an internal CY HNP procedure that describes the methodology for

-implementing the required quarterly groundwater sampling and analysis (RPM 5.3-0).

The GWMP Work Plan and Inspection Record (WP&IR) states specific permits, tags, and the required approval signatures needed to complete each quarterly sampling event.

The Groundwater Sampling Event Planning and Data Management procedure (RPM 5.3-3) documents what should be in a Groundwater Sampling Event Plan, including data quality objectives (DQOs), sample records, analysis parameters, and equipment. The methodology for representative sample collection and field measurements, including groundwater levels, are described in the Groundwater Level Measurement and Sample Collection in Monitoring Wells procedure (RPM 5.3-1) as attached in Appendix A.

Additional sampling event-specific plans were developed for the both the March and June 2004 sampling events. A Groundwater Sampling Event Plan was developed following guidelines set forth in the Groundwater Sampling Event Planning and Data Management procedure. All sampling and analysis was performed in accordance with the requirements of the GMP QAPP (Reference GMP QAPP 2004).

2

2 Groundwater Flow and Direction

2.1 Background

Groundwater elevation measurements are collected from each monitoring well sampled during the quarterly groundwater sampling events to provide a synoptic picture of hydrogeologic conditions at the facility. These groundwater elevation data are collected to develop an understanding of groundwater flow and direction, which are essential to assessment of plume status for the primary SOCs at HNP. The groundwater elevations were measured in accordance with the Groundwater Level Measurement and Sample Collection in Monitoring Wells procedure (RPM 5.3-1).

The groundwater and surface monitoring well network at HNP is shown by specific area in Figures 2-1 through 2-3. The EOF and parking lot area monitoring locations are shown in Figure 2-1, industrial area and upper peninsula area locations in Figure 2-2, and other peninsula area locations in Figure 2-3.

The characterization of hydrogeologic conditions at HNP is ongoing, with many factors that must be considered and evaluated before an accurate depiction of groundwater flow and direction can be developed. Site conditions such as definition and interconnection of hydrostratigraphic units, horizontal and vertical flow components, fractured flow elements, recharge/discharge zones, the impact of tidal influences, precipitation, and barometric pressure changes will be incorporated into the evaluation of hydraulic data. In addition, the mat sump hydraulic control operations and subsurface barriers to groundwater flow complicate the hydrogeologic conditions, and potentially the contaminant transport, in the industrial area. Another critical aspect concerning evaluation of groundwater flow and direction at HNP is providing an accurate datum to determine exact groundwater elevations during groundwater level gauging events.

As part of the plant characterization effort, measures have been recently implemented to ensure valid, consistent data are collected to provide adequate quality control for the evaluation of hydraulic data and development of the hydrogeologic conceptual site model (CSM) at the facility. A civil survey to establish horizontal and vertical position of a portion of the monitoring wells at HNP was performed by Kratzert and Jones of Middletown during November and December 2003 to address inconsistent well records, primarily in the industrial area. In addition to providing horizontal control for the wells surveyed, an accurate vertical datum was established for the wells surveyed to the nearest 0.01-foot, enabling adequate quality control to determine accurate groundwater elevations.

A network of pressure transducers was installed in selected groundwater monitoring wells and 2 surface water monitoring locations to collect continuous water levels and 3

temperatures throughout HNP for an extended period of time. The pressure transducers network was installed between January 14 and January 27 2004, and the pressure transducer have been collecting elevation data since January 27,2004. The groundwater elevation data collected from this network will enable evaluation of hydrogeologic conditions and refinement of the CSM.

The current hydrogeologic CSM at the HNP has identified three primary hydrostratigraphic units as part of the Phase I hydrogeologic characterization effort.

The current hydrostratigraphic unit designation is defined as follows: 1) the unconsolidated deposits, 2) the shallow bedrock, and 3) the deep bedrock. The unconsolidated deposits hydrostratigraphic unit is composed of the shallow, non-lithified clastic materials at the facility, including both sedimentary deposits and man-made fill. The shallow bedrock hydrostratigraphic unit is defined as the upper ten (10) feet of the bedrock interval, immediately underlying the unconsolidated unit Based on preliminary evaluation of hydrogeologic data, wells screened either across the unconsolidated deposits/bedrock interface or within the upper 10 feet of the bedrock display a hydraulic response similar to the unconsolidated deposits, rather than wells screened 10 feet or deeper within the bedrock interval, which is the current definition of the deep bedrock hydrostratigraphic unit Current understanding of the shallow bedrock hydrostratigraphic unit component of the hydrogeologic CSM suggests that it may contain partially weathered rock and, therefore, may be more intensely fractured than the deeper bedrock interval, possibly exhibiting a hydraulic response more characteristic of porous media than fractured media.

Table 2-1 provides well specifications for the groundwater-monitoring network. The information includes revised horizontal coordinates and the vertical elevation of the measuring points for water level gauging for each well, screen intervals, and the hydrostratigraphic unit monitored in each well.

Considering the complicated site conditions previously mentioned at HNP and the preliminary status of the hydrogeologic characterization effort, the evaluation of groundwater flow velocity and direction at the industrial area and upper peninsula area has not been finalized. Once the groundwater elevations are divided into the three hydrostratigraphic units, there are sparse data available for each unit, particularly for the deep bedrock. The presence of subsurface barriers to flow and foundation dewatering operations also complicate evaluation efforts.

The data from the recently installed pressure transducer network has been used to generate potentiometric maps for each of the three hydrostratigraphic units which provide a framework to evaluate groundwater flow and direction at the facility. The relationship between groundwater flow and direction at the industrial and upper peninsula areas, and the distribution of SOCs is discussed in Section 6 of this report.

2.2 March 2004 Groundwater Elevation Data A system of 33 data-logging pressure transducers was installed in monitoring wells at HNP and in the Connecticut River adjacent to the plant in January 2004. This system 4

was designed to provide a regular automated record of changes in water level elevation across the industrial portion of the site. The long-term water elevation data form the basis for meeting the following data needs:

• Quantify the horizontal hydraulic gradient across the site.

• Identify the apparent groundwater flow direction across the site.

Quantify the apparent vertical pressure differences between the identified aquifer units across the site.

• Identify aquifer response to recharge events (e.g., rainfall events) and groundwater extraction events (e.g., mat sump operation).

• Provide monitoring data for aquifer tests conducted as part of site characterization (e.g., aquifer pumping tests).

• Quantify aquifer response to tidal fluctuations and general river stage variations in the Connecticut River.

As a secondary data point, the pressure transducers also log water temperature at the same frequency as the water level.

The transducer system was installed starting in the last week of January 2004. The data loggers were initially set up to record measurements on one-minute intervals and were subsequently re-programmed to record measurements on five-minute intervals in May 2004. The transducers are routinely downloaded on a quarterly basis with more frequent downloads if data are required for specific needs. Significant events related to the water level monitoring system are shown in Table 2-2.

The transducer system includes two data-logging barometric pressure transducers.

These units are maintained at atmospheric conditions because the submersible transducers deployed in the monitoring wells are not barometric pressure-compensated.

The electronic data are downloaded from the monitoring well data loggers and the barometric pressure transducers using a portable computer. The data from the submerged transducers are then corrected for barometric pressure fluctuations using the data from the barometric pressure transducer(s) and proprietary software from the transducer manufacturer that calculates the corrected pressure indicated by the submerged transducers. The resulting pressure measurements are converted to water elevations by calculating the resultant height of the water column in each well at the time of measurement and adjusting for the measured well head elevation. The water elevations produced from the transducer data are then compared to periodic hand measurements collected using water level sounders for accuracy and precision assessment.

The detailed hydrographs for each instrumented location (i.e., the monitoring wells and the river) are included in Appendix B of this document. The hydrographs are presented by quarter and for each monitored location, three individual hydrographs are presented; one graph of the observed water elevation only, one graph of the water level and associated temperature, and one graph of the water level compared to total daily rainfall 5

as recorded at HNP. At the time of quarterly data collection; the transducer displayed in MW-1O1D was determined to have failed and produced erroneous results. The transducer has been repaired, but no hydrographs are presented for MW-1OlD. The overall hydrographs are summarized and discussed in the following subsections.

2.2.1 March 2004 Hydrographs The hydrographs for the first quarter of calendar year 2004 are discussed in the following narrative.

Connecticut River The Connecticut River exhibited strong, regular tidal fluctuation and only small variations in seasonal river stage during the period from January through March 2004.

Upon retrieval of the quarterly results in March, it was determined that the on-board batteries had failed in the transducer on February 25, 2004, apparently as a result of the cold temperature to which the unit was exposed. The transducer was restored to function on April 10, 2004.

An analysis of the hydrographs from the monitoring wells on site indicated that the water level in well TW-1 exhibits very close temporal and range efficiency with the river.

This is consistent with the proximity of TW-1 tothe river and the coarse nature of the formation in which the well is screened. A comparative analysis revealed that the river elevation was closely approximated by subtracting 1.37 feet from the observed elevation of groundwater in TW-1. This value, using TW-1 as a surrogate, was used to complete the river level hydrograph for the remainder of the first quarter and the affected portion of the second quarter.

Starting in early March 2004, the Connecticut River started to exhibit fluctuations that were apparently related to base flow changes in the river due to the start of the freshet.

The tidal fluctuation remains superimposed over the base flow fluctuations of the river.

The highest elevation (approximately 2.0 feet MSL) observed in the Connecticut occurred on March 11, 2004 during a high tide. A rising base flow shift started during the last week of March. Although the river stage does respond to the local rainfall, the drainage area of the Connecticut River is so large and rainfall sufficiently variable throughout the drainage that there is not always a good apparent correlation between observed river stage and local rainfall as recorded at HNP. The river exhibited a general elevation of 0 feet MSL +/- about 2 feet of regular fluctuation due to tide.

Reactor Foundation Mat Dewatering Sump The foundation mat dewatering sump, located adjacent to the reactor containment building on the plant-south side, has been in nearly-continuous operation for the life of the HNP. Evaluation of the construction drawings of the mat sump indicate that the sump is in apparent communication with all three of the hydrostratigraphic units identified at the site. A data logging pressure transducer was also placed in the sump to record water levels there. The mat sump is equipped with two submersible electric pumps that operate on a level control system to maintain a depressed water level in the sump. The sump pumps operate on a six-foot control level, with the pumps starting when water reaches approximately elevation -13 feet MSL, and stopping when water

,reaches approximately elevation -23 feet MSL. The long-term average dynamic water 6

level in the mat sump is approximately elevation -20 feet MSL. The mat sump was operating with a faulty level control when the transducer was installed on 4 February.

This resulted in operation of the pumps at a partial drawdown of the groundwater to an average elevation of about +3 feet MSL. The level control was repaired and the drawdown increased to about -17 feet MSL. Further adjustment of the level control system on 12 February resulted in the drawdown increasing to its current average level of -20 feet MSL. Because the mat sump is under continuous active pumping, the observed water level in the mat sump does not exhibit response to local rain fall events.

Unconsolidated deposits hydrostratigraphic unit:

All of the wells screened in the unconsolidated aquifer exhibited seasonal variations in water level. All of the wells that were sampled as part of the quarterly groundwater monitoring event exhibited transient drawdown effects during pumping for sample collection. The characteristics of the wells screened in the unconsolidated formation are summarized in Table 2-3. Several of the wells were observed to exhibit drawdown in response to dewatering activities in the foundation mat sump and in specifically-installed dewatering wells in the vicinity of the plant tank farm and the primary auxiliary building.

Shallow bedrock hydrostratigraphic unit:

Wells that are screened within the upper ten feet of the bedrock underlying the unconsolidated formation are considered to be in the shallow bedrock hydrostratigraphic unit. As with the unconsolidated formation wells, all of the wells that were sampled as part of the quarterly groundwater monitoring event exhibited transient drawdown effects during pumping for sample collection. The characteristics of the wells screened in the shallow bedrock formation are summarized in Table 2-4.

Several of the wells also were observed to exhibit drawdown in response to dewatering activities in the foundation mat sump and in specifically-installed dewatering wells in the vicinity of the plant tank farm and the primary auxiliary building. Hydraulic responses in wells completed in the shallow bedrock appear to mimic the responses observed in wells completed in the overlying unconsolidated formation. This suggests that in some locations, the shallow bedrock unit may be directly hydraulically connected to, and perhaps continuous with, the unconsolidated formation.

Deep bedrock hydrostratigraphic unit.

Wells that are screened deeper that ten feet into the bedrock underlying the unconsolidated formation are considered to be in the deep bedrock hydrostratigraphic unit. These wells generally exhibit hydraulic responses that are substantially different from those observed in the unconsolidated and shallow bedrock units. The characteristics of the wells screened in the deep bedrock formation are summarized in Table 2-5. The deep bedrock wells are generally not clearly and immediately responsive to local precipitation, however, most of them do exhibit pressure fluctuations that appear to be coincidental with the tidal fluctuations observed in the river. The temporal relation of the pressure transients observed in deep bedrock wells to the tidal fluctuations in the Connecticut River suggest that at least some of these wells exhibit the 7

characteristics of confined or semi-confined aquifer units. As with the wells completed in the other two units, the wells that were sampled as part of the quarterly groundwater monitoring event exhibited transient drawdown effects during pumping for sample collection. The characteristics of the wells screened in the deep bedrock formation are summarized in Table 2-5.

2-2.2 March 2004 Groundwater Flow Maps Groundwater flow maps for each of the three hydrostratigraphic units have been developed based on groundwater elevations measured on February 12,2004 (Table 2-6).

To evaluate potential impacts of tidal fluctuations on groundwater flow, groundwater flow maps for both high and low tides have been completed for each of the hydrostratigraphic units and are discussed in the following sections.

Unconsolidated deposits hydrostratigraphic unit:

Groundwater elevations and flow in the unconsolidated hydrostratigraphic unit for the first quarter sampling effort are shown in Figures 2-4 and 2-5 for both high and low tides.. The groundwater elevations measured in the unconsolidated hydrostratigraphic unit are representative of the water table surface in the plant property. Groundwater contours mapped in the unconsolidated unit are largely inferred, and generally consistent with the surface topography. Based on the inferred contours, groundwater flow in the unconsolidated unit is generally southwest, towards the Connecticut River.

The groundwater contours are mapped to depict discharge to the Connecticut River.

Although tidal changes do not appear to significantly alter the groundwater flow direction in the unconsolidated unit, monitoring wells adjacent to the river (e.g., MW-109S and MW-11OS) have water level elevations one to two tenths of a foot lower at low tide (Figures 2-4 and 2-5). Monitoring wells in the northern portion of the industrial area (e.g., MW-1O0S and MW-lOIS) are less impacted by tidal fluctuations, as measured groundwater elevations are typically on the order of one or two hundredths of a foot lower at low tide. The overall effects of the Connecticut River tidal change (approximately 0.5 to 0.75 foot) on groundwater flow in the unconsolidated unit is to create a slight decrease in the groundwater gradient adjacent to the river during high tide.

Groundwater flow in the unconsolidated hydrostratigraphic unit is impacted by the presence of subsurface barriers to flow. In the central portion of the industrial area several deep concrete structures are present from the ground surface to the top of bedrock. These structures include the reactor containment building (RCB), the discharge tunnel and the primary auxiliary building (PAB). As shown in Figures 2-4 and 2-5, the 10-foot and 5-foot groundwater contours are mapped much farther to the south in the western portion of the industrial area relative to the eastern portion 'of the site where the deep concrete structures are located. The displacement of the contours is a function of the presence of the subsurface concrete structures that impede groundwater flow in the unconsolidated unit in the area of the RCB, discharge tunnel, and PAB.

8

Another important feature in the industrial area is the presence of the mat sump. The sump is located adjacent to the southeast side of the RCB, and is installed approximately 40 feet below ground surface into the bedrock. The sump cycles regularly, keeping the water level in the sump between -23 and -17 feet below mean sea level (MSL). The presence of the sump creates a small, but deep depression in the groundwater surface, and with the RCB acts to inhibit flow in the unconsolidated unit (Figures 2-4 and 2-5).

Shallow bedrock hydrostratigraphic unit:

Groundwater flow in the shallow bedrock unit for the first quarter for both high and low tides is illustrated in Figures 2-6 and 2-7. The inferred groundwater contours are representative of the potentiometric surface of groundwater within the shallow bedrock as measured in monitoring wells screened within the shallow bedrock. Similar to flow in the unconsolidated unit, groundwater flow in the shallow bedrock is generally to the south and southeast towards the Connecticut River.

Tidal effects in the shallow bedrock of one to two tenths of a foot are observed in monitoring wells adjacent to the river (MW-109D and MW-508D), while only several hundredths of a foot variation occur in monitoring wells in the northern portion of the industrial area (MW-101D and MW-102D) (Figures 2-6 and 2-7). The tidal changes do not significantly impact groundwater flow in the shallow bedrock hydrostratigraphic unit.

Based on the large upward gradients observed in monitoring well pairs MW-109D/S and MW-11OD/S, groundwater in the shallow bedrock is interpreted to discharge to the Connecticut River. These monitoring well pairs are screened in the shallow bedrock and unconsolidated, respectively adjacent to the river. The strong upward gradients are consistent with both discharge to the river, and a flow direction towards the river.

A cone of depression associated with the mat sump is also present in the shallow bedrock unit (Figures 2-6 and 2-7). Groundwater levels in monitoring wells adjacent to the mat sump in the shallow bedrock indicate that a large area of influence occurs in the shallow bedrock (Figures 2-4 through 2-7).

Deep Bedrock hydrostratigraphic unit:

Groundwater flow in the deep bedrock unit for the first quarter for both high and low tides is illustrated in Figures 2-8 and 2-9. Groundwater flow in the deep bedrock hydrostratigraphic unit is characterized in a limited portion of the HNP, as deep bedrock monitoring wells are only present in the central and northern portions of the industrial area. The deep bedrock monitoring wells in this area are all influenced by the mat sump, and form a significant cone of depression in that area (Figures 2-8 and 2-9).

Interpretation of the hydrographs for the deep bedrock monitoring wells indicates that tidal influences are observed in these monitoring wells (Appendix B). Although deep monitoring wells are not present across the industrial area, the documented tidal influence in the deep bedrock wells indicates that outside the influence of the mat sump groundwater flow in the deep bedrock is towards the Connecticut River.

9

2.2.3 June 2004 Hydrographs The hydrographs for the second quarter 2004 time period are discussed in the following sections.

Connecticut River The adjusted water elevation recorded for well TW-1 was used as a surrogate to complete the hydrograph for the river during the first twelve days of the second quarter.

The Connecticut River continued to exhibit dear tidal fluctuations during the second quarter. The river also exhibited several cycles of rising base flow which peak on 4 April 2004 (peak river water elevation at +6 feet MSL), 15 April 2004 (peak river water elevation at +3.5 feet MSL), and 27 May 2004 (peak river elevation at +2.5 feet MSL). The general river water elevation during first half of the quarter was slightly above 0 feet MSL and slightly lower than 0 feet MSL during the second half of the quarter. The observed range of tidal fluctuation continued at +/- 1.5 to 2 feet.

Reactor Foundation Mat Dewatering Sump The mat dewatering sump continued in nearly continuous operation during the second quarter of 2004 with average dynamic water level at about -20 feet MSL. Two shutdowns were experienced from 18 April and 20 April 2004 and again from 28 May through 31 May. During the first event the water level recovered to a maximum elevation of +12 feet MSL and during the second event the water level recovered to a maximum of +8 feet MSL.

Unconsolidated deposits hydrostratigraphic unit:

All of the wells screened in the unconsolidated aquifer exhibited seasonal variations in water level. All of the wells that were sampled as part of the quarterly groundwater monitoring event exhibited transient drawdown effects during pumping for sample collection. The characteristics of the wells screened in the unconsolidated formation are summarized in Table 2-7. Several of the wells were observed to exhibit drawdown in response to dewatering activities in the foundation mat sump and in specifically-installed dewatering wells in the vicinity of the plant tank farm and the primary auxiliary building.

Shallow bedrock hydrostratigraphic unit:

Wells that are screened within the upper ten feet of the bedrock underlying the unconsolidated formation are considered to be in the shallow bedrock hydrostratigraphic unit. As with the unconsolidated formation wells, all of the wells that were sampled as part of the quarterly groundwater monitoring event exhibited transient drawdown effects during pumping for sample collection'. The characteristics of the wells screened in the shallow bedrock formation are summarized in Table 2-8.

Several of the wells also were observed to exhibit drawdown in response to dewatering activities in the foundation mat sump and in specifically-installed dewatering wells in the vicinity of the plant tank farm and the primary auxiliary building. Hydraulic 10.

responses in wells completed in the shallow bedrock appear to mimic the responses observed in wells completed in the overlying unconsolidated formation. This suggests that in some locations, the shallow bedrock unit may be directly hydraulically connected to, and perhaps continuous with, the unconsolidated formation. This is particularly apparent in the inland wells in the vicinity of the reactor containment building. In the riverward portion of the industrial area, the shallow bedrock unit more nearly mimics the deep bedrock with clear tidal influence and apparent response to changes in river stage. The characteristics of the wells screened in the shallow bedrock formation are summarized in Table 2-8.

Deep bedrock hydrostratigraphic unit Wells that are screened deeper that ten feet into the bedrock underlying the unconsolidated formation are considered to be in the deep bedrock hydrostratigraphic unit. These wells generally exhibit hydraulic responses that are substantially different from those observed in the unconsolidated and shallow bedrock units. The characteristics of the wells screened in the deep bedrock formation are summarized in Table 2-9. The deep bedrock wells are generally not dearly and immediately responsive to local precipitation, however, most of them do exhibit pressure fluctuations that appear to be coincidental with the tidal fluctuations and changes in river stage observed in the Connecticut River. The temporal relatiQn of the pressure transients observed in deep bedrock wells to the tidal fluctuations in the Connecticut River suggest that at least some of these wells exhibit the characteristics of confined or semi-confined aquifer units.

Well MW-101D exhibited a clear response to operation of dewatering well DW-3. The transducer in MW-101D, however, was found to be inaccurate and the response cannot be quantified. The clear response in MW-1OlD indicates apparent connectivity of.

fractures in the bedrock between the well locations. As with the wells completed in the other two units, the wells that were sampled as part of the quarterly groundwater monitoring event exhibited transient drawdown effects during pumping for sample collection.

2.2.4 June 2004 Groundwater Flow Maps Groundwater flow maps for each of the three hydrostratigraphic units have been developed based on groundwater elevations measured on June 12,2004 (Table 2-6). To evaluate potential impacts of tidal fluctuations on groundwater flow, groundwater flow maps for both high and low tides have also been completed for each of the hydrostratigraphic.units and are discussed in the following sections.

Unconsolidated deposits hydrostratigraphic unit Groundwater elevations and flow in the unconsolidated hydrostratigraphic unit for the second quarter sampling effort are shown in Figures 2-10 and 2-11 for both high and low tides. The groundwater elevations measured in the unconsolidated hydrostratigraphic unit are representative of the water table surface in the plant property. Potentiometric contours mapped in the unconsolidated unit are largely inferred, and generally 11

consistent with the surface topography. Consistent with the first quarter groundwater flow maps, groundwater flow in the unconsolidated unit is generally southwest, towards the Connecticut River. Groundwater elevations across the HNP are generally lower in the second quarter relative to the first quarter. The groundwater contours are mapped to depict discharge to the Connecticut River.

Similar to the observations in the first quarter, the tidal variations do have a significant impact on groundwater flow direction. Water level changes of up to only several tenths of a foot are observed in the high and low tide water levels (Figures 2-10 and 2-11).

The impacts of subsurface barriers interpreted in the first quarter results are also evident in the second quarter water levels. The five-and ten-foot cont6urs are displaced to the north in the central portion of the industrial area, consistent with the presence of subsurface barriers to groundwater flow (Figures 2-10 and 2-11). These structures include the reactor containment building (RCB), the discharge tunnel and the primary auxiliary building (PAB). The displacement of the contours is a function of the presence of the subsurface concrete structures that impede groundwater flow in the unconsolidated unit in the area of the RCB, discharge tunnel, and PAB.

The impact of the mat sump is also observed in the second quarter groundwater levels.

Consistent with the first quarter groundwater levels, the presence of the sump creates a deep depression in the groundwater surface, and with the RCB acts to inhibit flow in the unconsolidated unit.

Shallow bedrock hydrostratigraphic unit Groufdwater flow in the shallow bedrock unit for the second quarter for both high and low tides is illustrated in Figures 2-12 and 2-13. Similar to groundwater flow interpreted for shallow bedrock in the first quarter, groundwater flow in the shallow bedrock for the second quarter is generally to the south and southeast towards the Connecticut River.

Groundwater levels are somewhat lower in the shallow bedrock wells relative to the first quarter results, and the effects of the mat sump are somewhat greater in the area south and east of the RCB relative to the first quarter results (Figures 2-6, 2-7, 2-12 and 2-13).

Tidal effects in the shallow bedrock of one to two tenths of a foot are observed in monitoring wells adjacent to the river (MW-109D and MW-508D), while only several hundredths of a foot variation occur in monitoring wells in the northern portion of the area (MW-1O1D and MW-102D) (Figures 2-12 and 2-13). The tidal changes do not significantly impact groundwater flow in the shallow bedrock hydrostratigraphic unit.

The large upward gradients observed in monitoring well pairs MW-109D/S and MW-11OD/S in the first quarter results are also present in the second quarter, consistent with both discharge to the river, and a flow direction towards the river.

Deep bedrock hydrostratigraphic unit Groundwater flow in the deep bedrock unit for the second quarter for both high and low tides is illustrated in Figures 2-14 and 2-15. Consistent with the results for the first quarter, the deep bedrock monitoring wells in this area are all influenced by the mat sump, and form a significant cone of depression in that area (Figures 2-14 and 2-15).

12

Interpretation of the hydrographs for the deep bedrock monitoring wells indicates that tidal influences are observed in the deep bedrock hydrostratigraphic unit (Appendix B).

Although deep monitoring wells are not present across the industrial area, the documented tidal influence in the deep bedrock wells indicates that outside the influence of the mat sump groundwater flow is towards the Connecticut River.

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3 Groundwater Sampling and Analysis This monitoring report includes the radio-analytical and boron analytical results for two quarterly groundwater-sampling events. In addition, select geochemical analyses were performed on samples collected during the June 2004 sample event. One quarterly sampling event occurred between March 15 and March 18,2004. The other sampling event occurred between June 22 and July 6, 2004. The results of analysis of these samples are discussed in detail in Section 4.

The groundwater samples were forwarded to the GEL laboratory for radiochemical and boron analyses. This report includes discussion of data validation and provides a summary of the radio-analytical results and associated quality assurance (QA) data.

Some biases were observed in the radio-analytical data at low-level concentrations near the reported MDC. These positive and negative biases were observed in rank order trend plots for several nuclides. In some cases where a positive bias was observed, these results were concluded to be false positives and part of the underlying background or baseline distribution based on the homogeneity and normality of the results. These biases are generally limited to analyses performed via liquid scintillation counting (LSC) and gas proportional counting (GPC).

Measurements of field parameters were included as components of the groundwater sampling and are discussed in Section 3.1 and Section 3.2. A copy of the groundwater sampling procedure is contained within Appendix A.

Groundwater samples were collected by low-flow sampling methodology utilizing either a peristaltic pump or a stainless steel submersible pump with dedicated polyethylene tubing. As a result of low water level conditions, monitoring wells MW-102D and MW-103D were manually purged and sampled during both sample.

events with a dedicated polyethylene bailer rather than using a pump.'

3.1 Field Measurements Several types of field measurements were recorded in each well prior to sampling. Data obtained from these measurements included groundwater levels, the presence or absence of separate-phase fluid, and water quality parameters. These field measurements are essential components for the evaluation of water quality and hydrogeologic conditions at the plant.

Depth-to-water and bottom-of-monitoring-well sounding measurements were determined using an electronic water level meter with a 0.01 foot resolution. Water quality parameters recorded included specific conductance, pH, dissolved oxygen, temperature, oxidation-reduction potential and turbidity. These parameters are continuously measured prior to the sampling of each well until they have stabilized 14

within a 10 percent variation. This procedure is performed to confirm that well conditions have stabilized during the low-flow purging step, indicating enough water has been removed from the well so that a representative groundwater sample can be collected. These parameters were measured using a multi-parameter meter, with sensors arrayed within a flow-through cell. The resulting measurements are included within this report as Appendix C 3.2 Summary of Field Measurements The water quality parameter field measurements for the March and June 2004 sampling event are summarized in Tables 3-1 and 3-2, respectively. Field Daily Reports (FDRs),

which are field notes that document the sampling of each well, are provided in Appendix C. As recorded in the field notes, the field parameters typically stabilized within an acceptable range. One of the criteria for low-flow sampling methodology employed was to collect samples where the turbidity level had stabilized in the range of 5 to 15 nephelometric turbidity units (NTUs). This range is typically used to indicate the absence of fine silt and particulate matter that may adversely affect the analytical results of the groundwater sample. In general, with few exceptions, the turbidity levels of the groundwater samples were within this range and were fairly consistent with previously collected data.

As previously noted in past groundwater reports, pH continues to trend high at monitoring well MW-106D and 122D. During the March and June 2004 groundwater-sampling events, the pH readings from monitoring well MW-106D and 122D were reported to be in the 9.3 to 9.4 pH range. These wells have trended as high as 11.18 to 11.39 during the June 2001 sampling event. The most likely cause of the elevated pH in these wells is intrusion of cement grout into the screened intervals during well construction. Future pH measurements from this location will be monitored and evaluated closely.

3.3 Routine Lab Analyses and Locations All wells sampled as part of the two quarterly sampling events were analyzed for gross alpha, gross beta and gamma isotopic analysis. A number of industrial area monitoring wells were also sampled and analyzed for boron and stronium-90. A sub-set of these monitoring wells is routinely analyzed for select HTD radionuclides.

The locations that were sampled during the March 2004 event are located within the industrial area, peninsula and support building areas, as indicated below:

March 2004 Monitoring Event

• Industrial Area (28 samples from 27 wells in 17 clusters or locations):

MW-100D, S MW-liD, S MW-102D, S MW-103D, S MW-104S MW-105D, S MW-106D, S MW-107D, S MW-108S MW-109D(2), S MW-1OD, S MW-114S MW-115S MW-122D, S MW-123S MW-124S MW-125S 15

• Peninsula Areas (4 samples!):

MW-illS MW-112S MW-113S MW-117S

• Emergency Operations Facility Area (1 sample):

EOF-2 Both filtered and unfiltered groundwater samples were collected at the following locations during the March 2004 sampling event to provide analytical data to determine if metal concentrations are related to suspended particulate matter.

• Filtered Sample Locations (4 samples at 2 locations):

MW-105D, S MI W-106D, S Tune 2004 Monitoring Event Monitoring well MW-115S was not sampled during the June 2004 event due to insufficient water. The locations that were sampled are located within the industrial area, parking lot, peninsula and support building areas, as indicated below:

• Industrial Area (29 samples from 29 wells at 19 clusters or locations):

MW-1OOD, S MW-10iD, S MW-102D, S MW-103D, S MW-104S MW-105D, S MW-106D, S MW-107D, S MW-108S MW-109D, S MW-11OD, S MW-114S MW-122D, S MW-123S MW-124S MW-125S MW-1i MW-2 MW-3

• Parking Lot (8 samples from 8 wells at 6 locations):

MW-502 MW-503 MW-504 MW-505 MW-507D, S MW-508D, S

• Peninsula Areas (4 samples):

MW-illS MW-112S MW-113S MW-117S

• Emergency Operations Facility Area (1 sample):

EOF-2 The parking lot area wells were analyzed to provide additional boron and tritium distribution information for the northern side of the industrial area. The additional peninsula area wells (MW-1,2,3) were analyzed to provide additional Sr-90 distribution information (i.e., confirm previous detects at MW-117S).

Note that the landfills wells were not analyzed during these sample events. Sampling of the landfill wells has been suspended pending completion of remedial activities in the old landfill area.

Samples were analyzed for the following constituents and by the listed methodologies:

16

Boron via EPA method 6010B and 6020

• Gross Alpha via EPA method 900

• Gross Beta via EPA method 900

• Tritium via EPA method 906.0

• Gamma emitting fission and activation products by gamma spectroscopy

• Sr-90 via EPA method 905.5 and gas proportional counting Additional location-specific analyses are described below.

3.4 Special HTD Lab Analyses and Locations In addition to the above analyses, samples from a subset of various locations were analyzed during each sampling event via special analyses for Hard-To-Detect (HTD) plant-related radionuclides. These HTDs include alpha, beta and X-ray emitting, fission and activation product radionuclides. The subset of monitoring wells analyzed for HTDs, for both monitoring events, included the following:

• March & June 2004 Monitoring Event MW-103D,S MW-104S MW-105D, S MW-106D, S Each sample was analyzed for gross alpha, gross beta, tritium and gamma isotopic activity. In addition, the HTD analytes and analytical methodologies included the following-

• Carbon-14 via liquid scintillation

• Iron-55 via liquid scintillation

• Nickel-63 via liquid scintillation

• Plutonium-241 via liquid scintillation

• Stronium-90 via EPA method 905.5 and gas proportional counting

• Tc-99 via liquid scintillation

• Alpha-emitting transuranics (isotopic plutonium, curium, americium) via alpha spectroscopy

• Beta-emitting Pu-241 via liquid scintillation The results of analyses for HTD constituents in the subset of monitoring wells listed above are discussed below.

The results of analysis of the quarterly site-wide groundwater samples are discussed in Section 4.0.

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4 Laboratory Analytical Results The observed concentrations of the SOCs were compared to selected standards-in this instance, to the maximum contaminant level (MCL) promulgated under the Federal Safe Drinking Water Act regulations by the United States Environmental Protection Agency, and subsequently implemented by the State of Connecticut as the state's drinking water standards. The MCLs do not strictly apply to groundwater at HNP because the plant groundwater is not a source of community drinking water. The MCLs do, however, provide an accepted metric for comparison and evaluation of the apparent degree of groundwater contamination.

The MCL for beta and photon emitters (such as Sr-90 and Cs-137) is a dose-based 4 mrem/year, calculated using an agency-specified target organ dose methodology. The concentration of a single nuclide in water that would result in a dose of 4 mrem/year is often used as the MCL. This concentration is referred to as the C4 concentration, or the derived dose concentration. If only a single beta/photon emitter is present in drinking water, the derived concentration is the MCL for that nuclide. If, however, multiple beta/photon emitters are present in the sample, the fractional dose contribution of each nuclide is summed to determine the total dose. It may be noted that by applying the NRC Total Effective Dose Equivalent (TEDE) calculation method, the yearly dose corresponding to the MCL concentrations for tritium and Sr-90 would be less than 1 mrem/yr for each nuclide.

Thirty-seven (37) groundwater samples from thirty-six (36) locations within the existing site-wide monitoring well network were collected and analyzed during the March 2004 quarterly groundwater-sampling event. Boron and radiochemical analytical results are summarized in Appendix D.1 and complete lab analytical data packages are included as Appendix D.2. Total, or unfiltered, and filtered fraction groundwater samples were collected at several locations within the industrial area during the March 2004 round.

A total of thirty-nine (39) samples were collected for analysis from thirty-eight (38) monitoring wells during the June 2004 sampling event. Total, or unfiltered, and filtered fraction groundwater samples were collected at several locations within the industrial area during this round as well. The filtered fractions were field filtered with a 0.45-pm filter. Boron and radiochemical results are summarized in Appendix D.3 and complete lab analytical packages are provided in Appendix D.4.

4.1 Boron Boron is a good indicator element in groundwater at the HNP because it is chemically stable and was added to the water in the reactor vessel to control neutron flux when the plant was in operation. Therefore, the occurrence of elevated concentrations of boron in groundwater may be a general indicator of areas that have been impacted by previous releases.

18

Thirty-two (32) samples were collected as part of the March 2004 round resulting in thirty-one (31) samples detected greater than the Minimum Dete&tion Limit (MDL) of 0.54 micrograms per liter (ig/L). Results ranged from 38 jig/L at MW-107D to 767 pg/L at MW-105S (filtered). Results were not received from the lab for the MW-106S sample. Groundwater analytical results for the March 2004 boron analyses are summarized in Table 4-1.

Boron was detected in all forty-three (43) unfiltered and filtered samples analyzed in June 2004 with results from all above the MDC of 0.54 t+/-g/L. The highest concentrations were detected in wells MW-106S (490 pg/L) and MW-114S (1260 pg/L). Groundwater analytical results for filtered and unfiltered boron analyses are summarized in Table 4-1.

4.2 Gross Alpha The likely source of most gross alpha activity in the vicinity of HNP is dissolution of naturally occurring mineral deposits, including Radium (Ra) -226 and Ra-224, which are likely present in the underlying crystalline bedrock. Natural levels of gross alpha activity can range as high as a few hundred pCi/L. Although it is possible that plant-related radionuclides contribute to some of the observed gross alpha activity, it is not probable since alpha isotopic analysis generally results in non-detects with nominal detection sensitivity on the order of.0.3 pCi/L, or less.

Thirty-seven (37) samples were collected in March 2004 for gross alpha activity analysis resulting in seven (7) samples detected greater than the laboratory required Minimum Detection Concentration (MDC) of 3 picocuries per liter (pCi/L). None of the reported results exceeded the Environmental Protection Agency (EPA) maximum contaminant level (MCL) of 15 pCi/L. Gross alpha results for March 2004 are provided in Table 4-2.

Forty-three (43) samples were collected in June 2004 for gross alpha activity analysis resulting in thirteen (13) samples detected greater than the laboratory required Minimum Detection Concentration (MDC) of 3 picocuries per liter (pCi/L). Results at monitoring well MW-508S, 28 pCi/L, exceeded the Environmental Protection Agency (EPA) maximum contaminant level (MCL) of 15 pCi/L. Gross alpha results for June 2004 are provided in Table 4-2.

4.3 Gross Beta Gross beta activity in the vicinity of HNP may result from either naturally occurring or plant-related sources. Potassium-40 (K-40) is a radionuclide resulting from naturally occurring mineral deposits, which may account for relatively high percentage of gross beta activity in certain wells. High levels of gross beta activity in areas of plant-related contamination may be associated with beta emitters Sr-90 and Cs-137. The CT Public Drinking Water Quality Standard for gross beta radioactivity is 50 pCi/L though background levels may range as high as a few hundred pCi/L.

Twenty-seven (27) out of thirty-seven (37) samples analyzed detected gross beta activity greater than the laboratory required MDC of 4 pCi/L during the March 2004 sampling event. These concentrations ranged from 4.11 to 203 pCi/L. The highest gross beta activity concentration was identified in well MW-105S (filtered). This concentration is 19

greater than the CT Public Drinking Water Quality Standard MCL of 50 pCi/L. Gross beta results for March 2004 are provided in Table 4-2.

Twenty-eight (28) out of forty-three (43) samples analyzed detected gross beta activity greater than the laboratory required MDC of 4 pCi/L during the June 2004 sampling event. These concentrations ranged from 4.35 to 44.3 pCi/L. The highest gross beta activity concentration was identified in well MW-105S (filtered). All results were less than the CT Public Drinking Water Quality Standard MCL of 50 pCi/L. Gross beta results for March 2004 are provided in Table 4-2.

4.4 Tritium Results The presence of tritium in groundwater at HNP is the result of the nuclear fission reaction that was the heat source for the HNP nuclear power generating station.

Tritium was detected in twenty-three (23) of the thirty-seven (37) wells sampled.

Twenty-two of these detects were at concentrations greater than the required MDC of 400 pCi/L. All detected H-3 concentrations were below the C4 activity concentration of 20,000 pCi/L. The highest tritium concentrations were observed at monitoring wells MW-102S (6,740 pCi/L) and MW-103D (12,000 pCi/L). Tritium results for the March 2004 sampling event are summarized in Table 4-3.

Tritium was detected in twenty-four (24) of the forty-three (43) wells sampled.

Seventeen (17) of these detects were at concentrations greater than the required MDC of 400 pCi/L. All detected H-3 concentrations were below the Q activity concentration of 20,000 pCi/L. The highest tritium concentrations were observed at monitoring wells MW-114S (6,730 pCi/L) and MW-11OD (8,300 pCi/L). Tritium results for the June 2004 sampling event are summarized in Table 4-3.

4.5 Co.60 Any occurrence of Co-60 in groundwater at HNP is the result of plant-related processes.

Cobalt-60 was detected in two (2) wells at concentrations greater than the 2-a TPU level.

The Co-60 concentration ranged form 1.7 pCi/L at MW-108S to 3.2 pCi/L at MW-105S.

Only Co-60 concentration results at MW-105S were greater than the sample MDC during the March 2004 sample event.

Cobalt-60 was detected in seven (7) of the forty-three (43) samples analyzed during the June 2004 sample event. Results for five (5) wells were confirmed with replicate analysis. Only results at wells MW-104S (6.28 pCi/L) and MW-103S (11.4 pCi/L) were greater than the sample MDC. The detected values are well below the Q concentration of 100 pCi/L. Table 4-4 summarizes Co-60 results in all wells that were part of the June 2004 sampling round.

4.6 Cs-137 Any occurrence of Cs-137 in groundwater at HNP is the result of plant-related processes. Cesium-137 was detected in three (3) samples analyzed during the March 2004 event at concentrations greater than the 2-a TPU level. Only one (1) sample from well MW-103S out of the thirty-seven (37) samples analyzed detected Cs-137 above the 20 i

laboratory required MDC of 15 pCi/L, well below the Q concentration of 200 pCi/L.

Table 4-2 summarizes Cs-137 analytical results in all wells for the March 2004 sampling round.

The sample collected from MW-103S was the only well where Cs-137 was detected (7.5 pCi/L) out of the forty-three (43) samples analyzed during the June 2004 sampling event. This detected value is well below the C4 concentration of 200 pCi/L. Table 4-2 summarizes Cs-137 results in all wells that were part of the June 2004 sampling round.

4.7 Alpha Isotopic Results Alpha isotopic analyses including isotopic plutonium (Pu) and isotopic americium (Am) were determined by chemical separation and alpha spectroscopy. Isotopic plutonium analyses include the alpha emitters, Pu-238 and Pu-239/240 and Pu-241, which is a beta emitter. Isotopic americium and curium analyses include Am-241, Cm-242 and Cm-243/244.

All of the ninety-two (92) alpha isotopic results from the March 2004 sampling event were less than 2-c TPU and not statistically significant. Alpha isotopic results are summarized in Table 4-4. Two (2) results were observed with concentrations greater than the nominal sample specific MDC of 0.3 pCi/L. These results are believed to be false positive artifacts based on the following discussion.

Statistically significant activity is identified by concentrations that are greater than 2-a TPU and near the MDC level. One would expect a "false positive" rate of 2.5%

based on the area under the standard normal distribution around a limiting mean concentration of zero at the 95% confidence level. The observed positive rate for all alpha isotopic analyses was 0% for the March 2004 sampling event, which is on the order of the expected false positive rate if no significant alpha-emitters are present.

All forty (40) alpha isotopic for the June 2004 sampling event were non-detects with nominal sample specific MDCs or detection sensitivities on the order of 0.3 pCi/L or less. Table 4-4 summarizes alpha isotopic results for June 2004. The observed positive rate for all alpha isotopic analyses was 0% for the June 2004 sampling event. These sample analytical results suggest that the potential for statistically significant plant-related alpha activity in groundwater is small.

4.8 Sr-90 Results Strontium-90 in groundwater at HNP is also associated with past nuclear power operations. Fifteen (15) out of twenty-eight (28) samples analyzed for the March 2004 sampling event detected Sr-90 at concentrations greater than 2-a TPU, but only six (6) samples displayed values above the laboratory required MDC of 4 pCi/L. Only one (1) well contained Sr-90 concentrations that exceeded the Q concentration of 8 pCi/L.

Monitoring well MW-105S exhibited a Sr-90 concentration of 92.4 pCi/L. The Sr-90 analytical results for March 2004 are provided in Table 4-2.

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Seventeen (17) out of thirty (30) samples analyzed for the June 2004 sampling event detected Sr-90 at concentrations greater than 2-a TPU, but only four (4) samples displayed values above the laboratory required MDC of 4 pCi/L. Only one (1) well contained Sr-90 concentrations that exceeded the CQ concentration of 8 pCi/L.

Monitoring well MW-105S exhibited a Sr-90 concentration of 16.2 pCi/L. The Sr-90 analytical results for June 2004 are provided in Table 4-2.

Trend analysis of radionuclide data at these 2-a TPU levels and near the sample specific MDC has indicated the presence of bias in the Sr-90 analyses. Specifically, analytical results determined by liquid scintillation counting (tSC) and gas proportional counting (GPC) exhibited the most significant analytical bias. In most cases, the magnitude of the analytical bias was less than sample specific MDC.. Additional trend data, to be collected during future groundwater sampling events, will determine if these reported detections at the MDC level are statistically significant, or false positive values.

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5 Data Quality Assessment Current quality assurance/quality control (QA/QC) efforts in support of the Groundwater Monitoring Program at the Haddam Neck Plant (HNP) are designed to assess and enhance the reliability and validity of field and laboratory measurements conducted to support these programs. General quality requirements are provided in References LTP 2002 and GMP-QAPP 2002.

5.1 Data Quality Metrics On the analytical side, accuracy, precision, and detection sensitivity are the primary indicators used to assess laboratory data quality. These parameters are evaluated through laboratory QC checks (e.g., matrix spikes, laboratory blanks), replicate sampling and analysis, analysis of blind standards and blanks, and inter-laboratory comparisons.

Acceptance criteria have been established for each of these parameters. When a parameter is outside the criteria, corrective actions are taken to minimize future occurrence. Numerical criteria for evaluating precision, accuracy and completeness performance are generally available, while metrics for representativeness and comparability are more qualitative in nature.

5.1.1 Precision Precision was evaluated through the use of field duplicate samples and laboratory split or replicate samples. Field QC samples typically consist of duplicates, splits and blank samples. Field duplicate samples are used to assess sampling and measurement precision. Field split samples are used to assess measurement precision. Field splits and duplicates are typically examined to monitor laboratory operations and to identify potential problem areas where improvements are necessary.

One field duplicate sample was collected during the course of each quarterly sampling event, after considerations for well yield and sample volume requirements.

Approximately 25% of the total number of samples analyzed, for radiochemical and boron constituents were internal lab duplicates or replicates. Approximately 6% of the analyzed samples were analytical blanks.

5.1.2 Accuracy Laboratory performance is measured by several indicators, including nationally based performance evaluation studies, double-blind standard analyses, laboratory audits, and internal laboratory QA/QC programs. Measurement accuracy was evaluated by three methods:

• Calculation of percent recovery of laboratory control samples (e.g., calibration standards, blank spikes, and matrix spikes);

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• Comparison of reported minimum detectable concentration (MDC) to selected performance standards (e.g., drinking water standards);

• Comparison of method blank analyses to the MDC.

5.1.3 Completeness Completeness was evaluated by comparison of the number of valid measurements produced to the number of measurements planned. The target for completeness of valid measurements for all radionuclides for this sampling event was 100%. This objective was selected because critical sample locations (i.e., locations that define maximum concentration and/or maximum extent of contaminant plumes) have not been established for all radionuclides or geochemical constituents.

5.1.4 Comparability Comparability was evaluated qualitatively through assessment of sampling and measurement methods and apparent spatial distribution of substances of concern.

5.1.5 Analytical Bias Assessment A false-positive error is an instance when a nuclide or analyte is declared to be present but is, in fact, absent A false-negative error is an instance when an analyte is declared to be absent but is, in fact, present. Historically, commercial analytical laboratories used by CYAPCo have exhibited some difficulty with the reporting of false-positive results.

Sstatistical methods were employed to evaluate analytical bias with regard to the underlying baseline or background distribution.

5.1.6 Laboratory Audits/Assessments/Oversight Activities Laboratory activities are periodically assessed through surveillance and/or auditing activities to ensure that quality problems are prevented and/or detected. Periodic assessments support the continuous process improvement.

5.1.7 Issue ResolutiornCase Narrative Case narrative documents record detailed documentation of the analyses requested and provide additional documentation regarding problems encountered with sample receipt, sample analysis and data reporting. The forms are generated by the laboratory as required in the SOW and forwarded to the GW monitoring project with all hard copy data packages. The documentation is intended to identify occurrences, deficiencies and/or issues that may potentially have an adverse effect on data integrity.

5.2 Data Quality Results The data quality metrics for radiochemical constituents are summarized as follows:

Precision Relative Percent Difference (RPD) < 25% or within 2-a TPU of the Initial Value

• Accuracy Laboratory Control Sample Recovery 100% +/- 30 24

Laboratory Blank Analysis Results Non-Detect Laboratory Blank Analysis Results < MDC

• Representativeness Qualitative assessment of sample location, sample timing, sample collection method, sample preservation, handling, shipment

• Completeness Valid measurements for critical samples = 100%

• Comparability Qualitative assessment of sample collection and measurement methods Assignment of sample locations to hydrostratigraphic units.

Sample MDC < CRDL 5.2.1 Precision Results of the data quality assessment for precision are discussed in the following subsections.

52.1.1 Field Duplicates The duplicate sample for the March 2004 sampling round was collected from MW-114S, and identified as MW-210. This blind duplicate sample was analyzed for gross alpha, gross beta, H-3, Sr-90 and gamma isotopic nuclides. Results of the field duplicate evaluation are summarized in Table 5-2. Only those reported radiochemical results with a sample-to-uncertainty concentration ratio greater than 5 are evaluated and summarized. The uncertainty used in this ratio is the 1-a total propagated uncertainty for radiochemical results. Boron results that are greater than the contract required detection limit (CRDL) are also included in this evaluation. All evaluated field duplicate results are within 17% of the initial sample results, indicating satisfactory precision for the field duplicate samples.

The duplicate sample for the June 2004 sampling round was collected from MW-105S, and identified as MW-600S. This blind duplicate sample was analyzed for gross alpha, gross beta, H-3, boron, gamma isotopic and the hard-to-detect (HTD) nuclides. Results of the field duplicate evaluation are summarized in Table 5-3. Again, only those radiochemical results with a sample-to-uncertainty concentration ratio greater than 5 or boron concentrations greater than the CRDL are evaluated and summarized. All evaluated field duplicate results are within 7% of the initial sample results and indicate satisfactory precision.

52.12 Lab Duplicates Approximately 25% of the samples analyzed by GEL in a quarterly sampling event are internal or lab QC samples. These lab QC samples are comprised of lab control spikes, matrix spikes, method blanks, duplicates and replicates. The reproducibility of lab measurements is evaluated through the use of matrix duplicates. These duplicates are processed at a frequency of one matrix duplicate per batch. Internal acceptance criteria for duplicate samples are summarized as follows:

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• Accuracy within 20%

• Accuracy within allowed uncertainty and based on contract required detection limit (CRDL)

Sample and duplicate analysis results greater than 5 times the CRDL, must fall within

+/- 20% of the observed value. Sample or duplicate analysis results less than the product of 5 times the CRDL, the difference should be less than or equal to the CRDL.

Results of the lab duplicate evaluation for March 2004 are summarized in Table 5-4.

Seven (7) of eight (8) lab duplicate results are within 17% of the initial sample results and indicate satisfactory precision. Results for boron MW-114S replicate analysis were outside the acceptance criteria at +27.6%.

Results of the lab duplicate evaluation for June 2004 are summarized in Table 5-5. Five (5) of six (6) lab duplicate results are within 19% of the initial sample results and indicate satisfactory precision. Results for H-3 MW-11OS analysis were outside the acceptance criteria at -21.9%, but were within statistical agreement given the uncertainty of the measurements.

5.2.2 Accuracy Results of the data quality assessment for accuracy are discussed in the following subsections.

5.2.2.1 External Laboratory Performance Evaluations This section provides a detailed discussion of external performance indicators for the GEL laboratories. The GEL lab took part in US Department of Energy (DOE) Quality Assessment Program and the DOE's Mixed Analyie Performance Evaluation Program.

The GEL lab also participated in the Environmental Resource Associates (ERA)

RadCheMTm PT program. Results of those studies related to GW monitoring at HNP, are described in this section.

DOE Quality Assessment Program DOE 's Quality Assessment Program (QAP) evaluates how laboratories perform when they analyze radionuclides in water, air filter, soil, and vegetation samples. This program is coordinated by the Environmental Measurements Laboratory (EML) in New York City, New York. EML provides blind standards that contain specific amounts of one or more radionuclides to participating laboratories. Gamma emitters typically include K-40, Mn-54, Co-60, Cs-137, Bi-212, Pb-212, Bi-214 and Pb-214. Alpha emitters typically include U-234, Th-234, U-238, Pu-238, Pu-239, Am-241 and Cm-244. The beta and hard-to-detect (HTD) radionuclides typically include H-3, Fe-55, Ni-63 and Sr-90.

After sample analysis, each participating laboratory forwards the results to EML for comparison with known values and with results from other laboratories. Using a cumulative normalized distribution, acceptable performance yields results between the 15th and 85th percentiles. Acceptable with warning results are between the 5th and 15th 26

percentile and between the 85th and 95th percentile. Not acceptable results include the outer 10% (less than 5th percentile or more than 95th percentile) of historical data.

For the nine (9) QAP studies conducted from June 2000 through June 2004 (see References EML-608, 611, 613, 615, 617, 618, 621, QAP59 and QAP60), the percentages of acceptable or acceptable with warning results are summarized as a function of media and analysis type in Table 5-6. Overall, approximately 97.1% of the GEL data was in the acceptable or acceptable with warning performance category. For gamma isotopic analyses, 97.4% of the reported lab data was in the acceptable or acceptable with warning category. Approximately 98% of the alpha isotopic results and 94% of the HTD beta results were in the acceptable or acceptable with warning range. The DOE QAP60 program is the last performance that will be provided by the DOE.

DOE Mixed Analyte Performance Evaluation Program DOE's Mixed Analyte Performance Evaluation Program (MAPEP) examines laboratory performance in the analysis of soil and water samples containing metals, volatile and semi-volatile organic compounds and radionuclides. The program is conducted at the Radiological and Environmental Sciences Laboratory (RESL) in Idaho Falls, Idaho, and is similar in operation to DOE 's QAP discussed above. DOE evaluates the accuracy of the MAPEP results for radiological and inorganic samples by determining if they fall within a 30% bias of the reference value. Analytical results with a reported bias less than or equal to 20% are flagged as acceptable. Analytical results with a reported bias greater than 20% but less than or equal to 30% are flagged as acceptable with warning.

RESL provides blind standards that contain specific amounts of one or more radionuclides to participating laboratories. Gamma emitters typically include K-40, Mn-54, Co-57, Co-60, Zn-65, Cs-134 and Cs-137. Alpha emitters typically include U-234, U-238, Pu-238, Pu-239 and Am-241. The beta and hard-to-detect (HTD) radionuclides typically include Fe-55, Ni-63 and Sr-90.

The MAPEP program also uses false positive testing on a routine basis to identify laboratory results that indicate the presence of a particular radionuclide in a sample, when in fact the actual activity of the radionudlide is far below the required detection limit. False positive test nuclides typically include Sr-90, Fe-55 or Pu-238. Acceptable performance is indicated when the reported range encompassing the results (i.e., net concentration +/- 3-a uncertainty) included zero. Unacceptable performance is indicated when this range does not include zero.

For the ten MAPEP studies conducted through May 2002 (see References MAPEP-S6, S7, S8, S9, S10 and MAPEP-W7, W8, W9, W10, W11), the percentages of acceptable or acceptable with warning results are summarized as a function of media in Table 5-7.

Overall, about 96% of the GEL data was in the acceptable or acceptable with warning performance category for all media. For gamma isotopic analyses, 100% of the reported lab data was in the acceptable or acceptable with warning category. Approximately 96%

of 'the alpha isotopic results and 86% of the HTD beta results were in the acceptable or acceptable with warning range. GEL experienced some problems with the low level 27

false positive testing where 70% of the reported results were in the acceptable or acceptable with warning range.

ERA RadCheWM Proficiency Testing (PT) Program Environmental Resource Associates (ERAj RadCheMIm PT program is based on the National Standards for Water Proficiency Testing Studies Criteria Document (Reference NSWPT 1998). ERA examines laboratory performance in the analysis of water samples containing gross alpha/beta, naturals including uranium, mixed beta and gamma emitters. The program is conducted by ERA in Arvada, Colorado. ERA evaluates the accuracy of submitted results for radiological samples by determining if they fall within EPA or NELAC control limits.

ERA provides blind standards that contain specific amounts of one or more radionuclides to participating laboratories. Gamma emitters typically include Co-60, Zn-65, I-131, Ba-133, Cs-134, Cs-137 and Ra-226. Alpha and beta analyses typically include gross alpha, gross beta, H-3, Sr-89, Sr-90, Ra-228 and natural uranium.

The GEL lab participated in five (5) of the last (6) ERA studies (see References ERA-52, 53, 54,55 and 57). The percentages of acceptable or acceptable with warning results for these five (5) studies are summarized as a function of analysis type in Table 5-8. Overall, 98.4% of the GEL reported lab data was in the acceptable or acceptable with warning performance category for all media.

522.2 Field Blank Results A decontamination stationis typically established near monitoring wells sampled with non-dedicated equipment to provide for the proper decontamination of dedicated sampling equipment. All non-disposable equipment used during the program was subject to decontamination. These components included the groundwater sampling pump, electrical lead wires and support cable, as well as the flow-through cell in which field parameters were measured. An equipment rinsate blank sample was not collected during the March or June 2004 sample events since all monitoring wells were sampled using dedicated equipment.

5.22.3 Internal Lab Performance Evaluations Individual internal QC results are contained within Appendices D-1 and D-2 and indicate that the recovery rates for the laboratories are within acceptable ranges for the analyses performed. Approximately 25% of the samples analyzed by GEL in a quarterly sampling event are QC samples. These lab QC samples are comprised of lab control spikes, matrix spikes, method blanks, duplicates and replicates. Attached in Tables 5-9 and 5-10 is a summary of the number of QC samples processed by the GEL lab during the March and June 2004 sample events.

Internal Performance Criteria GEL performed a minimum of one laboratory control sample (LCS), one method or reagent blank (MB), and one duplicate sample analysis for each analysis performed in a batch of samples according to References GEL QAP 2003 and CY-ISC-SOW 2003. Batch sizes are composed of one to a maximum of 20 environmental samples. Matrix spike 28

(MS) samples are also analyzed when the analytical method involves chemical or physical separation and does not use an internal standard or carrier, and sufficient sample volume exists.

Internal acceptance criteria for LCS and MS samples are summarized as follows:

• Accuracy within QC acceptance limits (see Table 5-9)

• Results within 2-a TPU of the observed value

• Accuracy within allowed uncertainty and based on contract required detection limit (CRDL)

Matrix Spikes (MS) are first corrected for any ambient test nuclide activity. Samples with ambient activity greater than 4 times the expected value of the spike are not required to fulfill MS acceptance criteria. The activity levels of target analytes in LCS and MS samples are greater than 10 times but less than 100 times the a priori lower limit of detection (LLD). Acceptance criteria for LCS and MS samples are 75% to 125%.

Additionally, all QC and sample results must have chemical recoveries or chemical yields within the range of 15% to 125%.

Internal Performance Results for Accuracy The percentages of acceptable results are summarized as a function of analysis method in Table 5-12. Overall, about 95% of the GEL performance data for LCS and MS samples were acceptable according to performance criteria. For alpha isotopic and gamma isotopic analyses, 100% of the internal lab QC data was within acceptance limits.

Approximately 97% of the LSC results and 96% of the GPC results were within acceptable limits. GEL experienced some problems with the boron analyses where 64%

of the reported results were within acceptable limits.

Internal Performance - Method Blank Results Method or reagent blank results are evaluated or compared to the contract required detection limit (CRDL) and the lowest sample activity in a batch. Acceptable method blanks are those results that are less than the CRDL or less than 5% of the lowest sample activity, in the batch. Method blank results that do not meet the acceptance criteria are critically examined according to the GEL SOPs and documented through GEL's nonconformance reporting (NCR) system. Method blank failures are also documented in the case narrative of the analytical report. 'Method blank activity levels are not subtracted from sample activity levels.

5.2.3 Completeness Valid results were generated for a total of 692 radionuclide tests, resulting in completeness of 99.9%. The requested boron analysis for MW-106S was not reported.

For the June 2004 sampling event valid results were generated for 715 radionuclide tests, resulting in a completeness of 100%.

5.2.4 Comparability Comparability was evaluated qualitatively through assessment of sampling and measurement methods and apparent spatial distribution of substances of concern. The 29

analytical methods used for this determination are comparable to methods used to measure dissolved species in natural waters. The sampling method and analytical techniques used in both sampling events were comparable to previous events, with the exception of the analysis of field filtered samples at some industrial area locations.

These results generally indicate that boron and radiochemical constituents detected in all wells was present in a soluble form and the filtered results are comparable to the current and previous unfiltered measurements.

5.2.4.1 Sample Methods Sample collection and control was performed using work processes and trained staff according to References RPM 5.3-0, GW-WPIR 2001 and RPM 5.321. The tasks included sample planning, sample collection, chain-of-custody preparation and sample shipping.

The General Engineering Lab (GEL) in Charleston, SC was used as the primary lab for the radiological and boron analyses. Methods employed for radiological constituents were developed by the vendor laboratory and are recognized as acceptable within the radiochemical industry. The boron methods employed were standard EPA methods.

The contract required detection limits (CRDL) are identified in the laboratory Statement of Work (CY-ISC-SOW 2003) are summarized in Table 5-1.

The GEL lab supplied all sample containers used in the collection of the groundwater samples that they analyzed. Sample containers were delivered to the site by courier and maintained in a secure manner until use by the sampling team. Samples were packaged for transport to the laboratory with protective packing material in insulated coolers with custody seals.

The on-site HNP laboratory performed tritium and gamma isotopic analyses to support off-site sample shipments. These analyses were not used for reporting actual groundwater analytical sample results.

5.2A.2 Radiochemical Data Reporting Convention All reported analytical results include the net concentration, the 1-o or 2-a total propagated uncertainty concentration (TPU), and the minimum detectable concentration (MDC). Net concentration results greater than the 2-a TPU generally imply that statistically significant activity is present with a 95% certainty. Net concentration results less than the 2-o TPU indicate zero or statistically insignificant activity. Net concentration results reported as negative values imply that the radioactivity in the sample is less than the average or long-term background.

The reported TPU is a combination of the counting uncertainty and any other factors that contribute to the overall uncertainty including uncertainties in the sample mass, chemical yield and determination of calibration factors. Total propagated uncertainty values reported at 2-a allow direct comparison with the net concentration for statistical significance. Total propagated uncertainty values reported at 1-a are converted to 2-a for comparison purposes.

Detection limits are essential for evaluating data quality and demonstrating that the desired sample analytical sensitivity was achieved. The lower limit of detection (LLD) is 30

the lower limit at which a measurement can be differentiated from background with some degree of confidence. The LLD for a radionuclide is typically computed from the counting error associated with the instrument background, or blank counting conditions, at the time of analysis and is usually expressed in terms of counts, or count rate. In contrast, the MDC includes conversion factors to relate background count rate to radionuclide activity or concentration. The contractual (or a prion) MDCs for these results identified in the laboratory Statement of Work (CY-ISC-SOW 2003) are summarized in Table 5-1. These contract required detection limits (CRDL) are based on the resident farmer scenario with a 1 millirem per year Total Effective Dose Equivalent (TEDE) annual dose. All reported MDC concentrations are a posteriori and include sample specific corrections for radioactive decay, chemical yield and sample mass.

52.4.3 Radiochemical Data Review All analytical results in the form of the sample specific MDC were evaluated against the contractual MDCs to ensure that sensitivity requirements were met. The sensitivity requirement is relaxed when statistically significant activity is identified in order to conserve lab cost and instrument resources. Several instances were identified in the case narrative where required sensitivities were not achieved (i.e.; the sample specific MDCs were greater than the CRDL). In some cases this is attributed to a small sample mass or a low chemical recovery resulting in a low recovered sample mass. Ideally, these samples are reanalyzed with a larger sample volume, when available. In all cases, the CRDL for Am-241 of 0.5 pCi/liter was not achieved when analyzed by gamma spectrometry, but it was easily achieved by alpha spectrometry. Results that were statistically significant were tracked and trended with previous results. Results greater than the MCL and CRDL requires continued sampling.

Simple rules of thumb were used to evaluate analytical results that were not statistically significant with respect to background. Based on the theoretical relationship of the 1-a net concentration uncertainty and the 1-a background concentration uncertainty (which is the basis for the MDC), the MDC-to-uncertainty ratio was evaluated numerically for consistency and reasonableness. In this case, the 2-a TPU uncertainty was used as the estimator for the 1-c net concentration in the evaluation and MDC-to-uncertainty ratios less than 1.5 were flagged for additional review. These thumb rules do not apply to low count rate results typical of alpha isotopic analyses where MDC-to-TPU ratios can span the range from 1 to 25.

5.2.5 Issue Resolution/Case Narrative Case narrative documents record detailed documentation of the analyses requested and provide additional documentation regarding problems encountered with sample' receipt, sample analysis and data reporting. The forms are generated by the laboratory as required in the SOW and forwarded to the GW monitoring project with all hard copy data packages. The documentation is intended to identify occurrences, deficiencies and/or issues that may potentially have an adverse effect on data integrity. These case narratives are included in Appendixes D.1 and D.2 with the laboratory analytical data sheets. Specific issues identified by the GEL lab during the reporting of March 2004 sampling event data included:

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• The serial dilution for boron did not meet the acceptahce criteria of less than 10%

for the ICP and ICPMS batches. Serial dilution is used to assess matrix suppression or enhancement.

• Gross alpha and beta samples MW-113S, MW-113S and the LCS samples were reprepped due to recovery outside acceptance criteria.

• High hygroscopic salt content in evaporated samples can cause the sample mass to fluctuate due to moisture absorption during gross alpha and beta sample preparation. The salts were converted to an oxide by heating under a flame.

Volatile radioisotopes of carbon, hydrogen, technetium, polonium and some cesium may be lost during this process.

• Samples MW-101D and MW-105D (filtered) were recounted for americium alpha isotopic analysis due to a peak shift.

• Samples MW-106D (filtered), MW-123S, method blank, MW-123S duplicate, MW-123S matrix spike and the LCS samples were reprepped due to carrier yield.

• The Pu-241 sample batch was recounted due to high MDCs. An NCR was issued for Pu-241 samples MW-103S and MW-105S (filtered) which did not meet the CRDL after counting for 180-minutes each.

• Gross alpha results for MW-114S matrix spike and matrix spike duplicate did not meet the alpha recovery requirements due to sample matrix effects.

• The Sr-90 results for MW-103S, MW-105S, MW-105S (filtered), MW-106S, MW-106S (filtered), MW-106S lab duplicate, MW-114S, MW-114S field duplicate, MW-115S and MW-125S were verified by recounting the samples at least 5-days from the initial count.

• The Fe-55 sample batch was recounted due to extremely negative results. The reported negative concentrations were greater than three (3) times the error due to the Fe-59 cross-talk correction.

• The Fe-55 samples for MW-106D matrix spike and the LCS were recounted due to low/high recovery.

Specific issues identified by the GEL lab during the reporting of June 2004 sampling event data included:

• The H-3 sample bottles for MW-507D and MW-507S leaked during transit. The H-3 aliquots were retained from preserved aliquots and neutralized prior to analysis.

• Manual integration of the plutonium alpha energy spectra was performed for the method blank sample, to separate regions-of-interest.

• Gross alpha/beta samples MW-108S and MW-108S lab duplicate were recounted due to recovery outside acceptance criteria.

• High hygroscopic salt content in evaporated samples can cause the sample mass to fluctuate due to moisture absorption during.gross alpha and beta sample preparation. The salts were converted to an oxide by heating under a flame.

Volatile radioisotopes of carbon, hydrogen, technetium, polonium and some cesium may be lost during this process.

• The Sr-90 results for MW-125S, MW-103S and MW-106S were verified by the gross beta results. The Sr-90 results for MW-105S, MW-105S field duplicate, 32

MW-107S and MW-122D were verified by recounting at least 5-days from the separation date.

• Results for Fe-55 batch are extremely negative due to the Fe-59 cross-talk correction. The reported negative concentrations were greater than three (3) times the error.

• An NCR was generated for batch control of plutonium alpha isotopic and Pu-241 samples. Samples were not scanned into the LIMS system prior to analysis.

• The lab duplicate sample for gross alpha/beta analysis MW-109S was recounted due to a high relative percent difference/relative error ratio. The matrix spike sample for gross alpha/beta analysis MW-109S was recounted due to a low/high recovery.

• Sample MW-105D for Fe-55 was recounted due to low/high recovery. Samples MW-105D and MW-103D for Fe-55 were recounted to verify activity. The recounts are reported.

• Samples MW-107S and the method blank for H-3 were recounted due to spectral interferences.

• Sample MW-2 for H-3 was recounted due to high relative percent difference/relative error ratio. Samples MW-2, MW-117S, method blank and the lab duplicate (MW-2) were recounted for H-3 due to high lumex and low quench numbers.

In some cases, these occurrences initiated internal non-conformance action on the part of GEL Charleston lab with additional follow-up documentation. CYAPCo is specifically working with the lab to resolve the Fe-59 cross-talk correction issues identified above and through trend analysis of the Fe-55 data. We will continue to monitor these case narratives and their impact on lab data quality.

5.2.6 Representativeness Representativeness of sample analyses was evaluated qualitatively. The following observations relative to sample representativeness were made:

52.6.1 General Samples collected during the March and June sampling events exhibited variability in turbidity. The cause of this variability is not apparent, but probably results from accumulation of fine geologic material in the wells due to variations in degree of well development as well as variations in the content of fine material at the various locations sampled. Redevelopment of existing monitoring wells should be considered to attempt to provide samples with more uniform turbidity across the site. Comparison of observed turbidity measurements to analysis of radiochemical constituents in both filtered and unfiltered samples indicates no apparent correlation. Essentially all observed radiochemical constituents appear to be present in a soluble state. Therefore it is concluded that variations in sample turbidity did not affect radiochemical analyses.

Monitoring wells have been allocated to unique hydrostratigraphic units based on the relative placement of screened intervals. These units vary from the previous assignment of well pairs as either "deep" or "shallow". Three discrete units have been idertified as follows - 1) an unconsolidated formation defined as the

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unconsolidated material overlying bedrock; 2) shallow bedrock, defined as the upper ten feet of bedrock underlying the unconsolidated formation, regardless of depth below ground surface; and 3) deep bedrock which consists of the bedrock formation below the uppermost ten feet of bedrock. This assignment of wells to unique hydrostratigraphic units affects interpretation of results with respect to the spatial distribution of substances of concern.

• Samples collected from wells MW-106D and MW-122D exhibited elevated pH relative to other wells at the site. The cause of the elevated pH is not apparent and could result from either natural processes (e.g., encountering localized carbonate-rich rock) or from man-made processes. Review of well logs indicates that these wells were constructed using 2-inch diameter casing inside 3-inch boreholes. The elevated pH may result from intrusion of cement grout into the screened interval during well construction in these inadequately-sized boreholes. These two wells also exhibit higher dissolved carbonate concentrations than other deep wells.

5.2.6.2 Boron

• Boron contamination is likely present in groundwater at HNP as the orthoborate oxyanion (BO3r3) which results directly from aqueous dissolution of boric acid (H3BO3). Substantial quantities of boric acid solution were historically released from the former HNP tank farm and potentially from other locations within the industrial area. In addition to plant-related boron in groundwater, there appears to be a measurable naturally-occurring boron background concentration. A definitive background boron study has not been performed at HNP, however, inspection of the boron analytical results suggests that a natural boron background concentration of about 50 pg/L or less is present at the site. The actual ionic species of naturally-occuring boron at HNP is not defined and may differ from the orthoborate ion.

Observed boron concentrations of greater than 100 ug/L appear to be related to plant-related releases. It is difficult to discern the apparent source of boron concentrations in groundwater between 50 lig/L and 100 jig/L; thus, the distal boundaries of plant-related boron plumes are not clearly defined.

• Monitoring wells have been allocated to unique hydrostratigraphic units based on the relative placement of screened intervals. These units vary from the previous assignment of well pairs as either "deep" or "shallow". Three discrete units have been identified as follows -1) an unconsolidated formation defined as the unconsolidated material overlying bedrock; 2) shallow bedrock, defined as the upper ten feet of bedrock underlying the unconsolidated formation, regardless of depth below ground surface; and 3) deep bedrock which consists of the bedrock formation below the uppermost ten feet of bedrock. This assignment of wells to unique stratigraphic units affects interpretation of results with respect to the spatial distribution of substances of concern. The highest concentrations of boron observed at HNP are reported in shallow wells, with high concentrations historically found in the immediate vicinity of apparent release areas. The boron concentration in deep bedrock wells is substantially less than that in the areas of apparent contamination, although boron was detected in all but one sample collected in March and'samples collected in June. This is consistent with the presence of a measurable boron background at the site.

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• Boron is expected to be present in groundwater as a soluble oxyanion and, therefore; the measured concentrations are not expected to be affected by variations in sample turbidity. The low-flow sampling method is expected to produce representative samples for boron analysis.

5.2.7 Lab Audits No onsite audits or assessments were conducted at the GEL facility during this time period. A commercial grade survey was performed initially, prior to sending samples to the GEL. As a result of this evaluation, GEL was placed on the CYAPCo Approved Suppliers List. In addition, an Annual Supplier Evaluation was performed by the CYAPCo nuclear safety department.

5.2.8 Analytical Bias Assessment A false-positive error is an instance when a nuclide or analyte is declared to be present but is, in fact, absent. A false-negative error is an instance when an analyte is declared to be absent but is, in fact, present. Historically, commercial analytical laboratories used by CYAPCo have exhibited some difficulty with the reporting of false-positive results, based on MAPEP performance evaluation (PE) data and trend analysis of analytical sample results. These difficulties were generally limited to radioisotopes analyzed via liquid scintillation counting (LSC) and to a lesser extent, gas proportional counting (GPC).

Positive trends and biases have been observed in the past with the following nuclides analyzed via LSC at levels near the reported MDC: Fe-55, Ni-63, Tc-99 and Pu-241. Low-level analytical positive trends have also been observed for Sr-90, gross alpha and gross beta analyses, which are analyzed via gas proportional counting (GPC). Significant trends with gamma or alpha isotopic analysis results are less common.

A positive bias was observed for C-14 results analyzed via LSC during the March sample event. The magnitude of the positive bias was less than the analysis sensitivity or average MDC. Positive bias was also observed in the gross alpha and gross beta results analyzed by GPC methods. No bias was observed for gamma isotopic analysis methods. Negative biases were observed for Fe-55, Ni-63 and Tc-99, which were all analyzed by [SC.

A positive bias was observed for H-3 analyzed via LSC during the June sample event.

The magnitude of the positive bias was less than the analysis sensitivity or average MDC. Positive bias was also observed in the gross alpha, gross beta and Sr-90 results analyzed by GPC methods. A positive bias was observed in the Co-60 results analyzed by gamma spectrometry. A negative bias was observed for Fe-55 results analyzed by

[SC.

Statistical and visual methods were employed to evaluate trends in the analytical results as a function of nuclide. Rank order plots for the March and June 2004 sample events 35

were prepared as a function of nuclide (see Appendix E). The analytical data were treated as follows:

• Net concentration resudts at all well locations were arraniged in ascending order

• Standard distributional statistics were calculated (i.e., mean, median, minimum, maximum and standard deviation for the net concentration, 2-a TPU and MDC)

• Net concentration results with associated TPU error bars were graphed as a function of rank order

• Expected zero mean concentration and 2-a zero mean concentration control limits graphed as a function of rank order

• Average MDC graphed as a function of rank order Graphing the expected zero mean and associated 2-a zero mean concentration control limits provides a visual indication of biases in the analytical technique at concentration levels near or below the MDC. The expected +/- 2-a zero mean control limits were based on actual sample data when activity was near or less than the MDC. In most cases, the average 2-a TPU provides restrictive control limits that are more sensitive than the standard deviation of the mean concentration, which is subject to the influence from positive outliers. For analyses that were generally statistically significant with respect to background (i.e., gross alpha, gross beta), analytical blank data were used to estimate the 2-a zero mean control limits.

Statistical methods were used in order to accurately identify and quantify biases in analytical lab data. Some basis statistical parameters for the March and June 2004 events are summarized in Tables 5-10 and 5-11, respectively. These methods included segregation of the analytical data into logical subsets, use of outlier detection methodology, and identification of statistical significant bias. Logical data subsets were typically comprised of an individual nuclide by sample event or sample analysis batch.

For LSC analysis, a logical subset may consist of samples counted in a single batch. Due to the number of samples collected, multiple batches may be processed for each analyte in a typical sampling event.

A typical groundwater analysis data subset (i.e., by nuclide) was assumed to be comprised of two distributions, an underlying background or zero analyte component randomly distributed around zero, and an unknown spatially or temporal varying distribution characterized by statistically significant or higher analyte concentrations. In most circumstances, the limiting mean value of the underlying blank is expected to be a constant with random fluctuations normally distributed around zero, after correcting for.

instrument background or blank conditions. In the case of a systematic bias in the blank, the limiting mean value of the blank distribution will be normal and randomly distributed around a non-zero (i.e.; positive or negative) value. When the data are sorted in ascending order with regard to analyte concentration, the underlying background will be distributed on the low analyte concentration end while the spatially or temporally varying analyte results (i.e., statistically significant results), will be distributed on the high concentration end of the data sub-set.

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Given the rank order of the daIta set, a modified Z-score meth6d was used starting on the low analyte concentration end, to identify statistical outliers on the high analyte concentration end of the data set. The Z-score test is a standard statistical method to identify outlier data. Positive outliers as identified were assumed to be nonzero or part of the spatially or temporally distributed data. All others results were considered to be part of the zero analyte or baseline distribution. The limiting mean and standard deviation of these baseline mean results were used as an indicator for technique bias at concentrations near the MDC.

The underlying background or baseline data were evaluated for normality based on Filliben's r-statistic, also known as the normal probability plot correlation coefficient Filliben's r-statistic6 near unity are characteristic of normally distributed data. Results of the normality testing for the March and June 2004 sample events are summarized in Tables 5-12 and 5-13, respectively. Standard hypothesis testing was also used to determine if the limiting mean bias was statistically different from zero. The limiting mean baseline results were evaluated for statistical significance using the Student's t-test. In order to concentrate our efforts on analyses with the most significant bias, we used a 3-a criterion to identify with a high degree of confidence (i.e., at the 99.97 %

confidence level) analyses with significant bias with respect to the underlying background or baseline. Our selection of a 3-a criterion in this case is based on conventional control chart theory where the analytical technique is said to be in control (i.e., no apparent bias) when the observed limiting mean value is within +/- 3-ca of the expected zero analyte concentration. Results of t-testing for the March and June 2004 sample events are also included in Tables 5-12 and 5-13, respectively. Some typical examples of the application of these statistical based methods as a function of general analysis type or nuclide-of-interest are as follows.

5.2.8.1 Gamma Emitters Manganese-54 is a gamma emitter, determined by photon counting or gamma isotopic analysis. Manganese-54 is produced by neutron reactions with structural stainless steel and has an expected low radionuclide inventory due to a short radioactive half-life of 312.7 days. It has decayed through greater than 7 half-lives since plant shutdown and less than 0.5% of its shutdown activity or inventory remains. Mn-54 is not expected to be present in detectable quantities in groundwater samples from the HNP and is a good candidate analysis to demonstrate a zero analyte or underlying background distribution.

Figure 5-1 is a rank order plot of Mn-54 concentrations in groundwater for the March 2004 sampling event. The Mn-54 results are graphed with their corresponding 2-a TPU error bars. An average and 1-u standard deviation concentration of -0.31 i 0.73 pCi/L was observed in this data set while the average MDC was 3.1 pCi/L. The control limits are +/- 1.45 pCi/L based on the 2-ca standard deviation of the limiting mean.

Approximately half the data points are distributed above or below the zero concentration level. Note that the 2-a TPU error bars generally cross zero except in. the extreme positive or negative regions of the data.

The limiting mean value of -0.31 pCi/L is statistically equal to a zero concentration level based on the t-statistic and 34 (n-i) degrees of freedom. The data are also normally 37

distributed around the limiting mean value as illustrated by the frequency distribution in Figure 5-2. As expected, no significant Mn-54 activity is indicated in this trend plot and the data are equally distributed around zero. These results are typical of gamma isotopic analysis where no analyte is present and the background or energy baseline is easily and accurately determined.

Cesium-137 is a gamma emitter, determined by photon counting or gamma isotopic analysis. Cesium-137 is a fission product with a 30.17-year radioactive half-life. Due to a high radionuclide inventory and radioactive half-life, or decay considerations, Cs-137 has been detected in groundwater samples from the HNP.

Figure 5-3 is a rank order plot of Cs-137 concentrations from the March 2004 sampling event. Only results with concentrations less than 10 pCi/L are displayed in order focus attention on the underlying baseline distribution. An average and 1-a standard deviation concentration of -0.30 i 1.03 pCi/L was observed for the limiting zero mean while the average MDC was 3.4 pCi/L. The control limits are +/- 2.06 pCi/L based on 2-a standard deviations of the limiting mean. Results with concentrations greater than 2.84 pCi/L were determined to be statistically different from the underlying background based on outlier testing. The baseline data are normally distributed around the limiting mean value of -0.30 pCi/L in Figure 5-4 and the limiting mean value is not statistically different from zero, based on the t-test. These results are again typical of gamma isotopic analysis with zero analyte data.

Cobalt-60 is a gamma emitter with a high radionuclide inventory at INP due to its presence in structural material. Cobalt-60 has a radioactive half-life of 5.271-years and about 42% of its shutdown inventory or activity remains. Cobalt is a common impurity in stainless steel and is the dominant external dose producing isotope in reactor interior components on a 10-year time scale.

Figure 5-5 is a rank order plot of Co-60 concentrations in groundwater for the June 2004 sampling event. An average and 1-a standard deviation concentration of 0.43 +/- 0.74 pCi/L was observed for the limiting zero mean while the average MDC was 3.5 pCi/L. The control limits are +/- 1.48 pCi/L based on 2-a standard deviations. The baseline data are normally distributed around the limiting mean value of 0.43 pCi/L (Figure 5-6). The limiting mean is statistical greater than zero based on the t-test. There were six (6) positive outliers in this Co-60 data set.

It is important to note that Co-60 is also a common trace contaminant in materials used in the construction of high-purity germanium (HPGe) detectors. These HPGe detectors are used for the gamma isotopic analyses. It is not uncommon to observe Co-60 peak background response rates on the order of 0.001 count per second, depending on the HPGe detector size and configuration. Given the sensitivity requirements for these analyses, the ability to accurately distinguish low-level Co-60 (i.e., pCi/L amounts) in groundwater from the detector background contribution is non-trivial. These results are typical of gamma isotopic analysis where the underlying baseline distribution is homogenous and normally distributed, and the presence of statistically significant Co-60 38

is indicated near the MDC. In the past, we have observed positive biases for Co-60 on the order of.0.4 pCi/L.

5Z8.2 Beta and X-Ray Emitters via LSC Figure 5-7 is a rank order plot of C-14 concentrations in groundwater for the March 2004 sampling event. C-14 is a beta emitter, determined by chemical separation and LSC.

Due to an expected low radionuclide inventory, C-14 is not expected to be present in detectable quantities in groundwater samples from the HNP. An average and 1-a standard deviation concentration of 72.3 i 41.0 pCi/L was observed in this data set while the average MDC was 155 pCi/L. The control limits are +/- 82.0 pCi/L based on the average 2-a standard deviation. Note that all of the data points are distributed above the zero concentration level.

The limiting mean value of 72.3 pCi/L is statistically greater than the zero concentration level based on the t-statistic and 11 (n-1) degrees of freedom. The data are also normally distributed around the limiting mean value as illustrated by the frequency distribution in Figure 5-8. A significant positive bias is indicated in this trend plot and the data are equally distributed around the limiting mean. These results are typical of LSC analysis where a significant positive systematic bias in the underlying baseline distribution exists.

Figure 5-9 is a rank order plot of Fe-55 in water for the June 2004 sampling event. Iron-55, which decays by electron capture and subsequent X-ray emission, is determined by LSC analysis. Iron-55 has a radioactive half-life of 2.7-years and only 19% of its shutdown inventory or activity remains. An average and 1-a standard deviation concentration of -22.8 i 4.1 pCi/L was observed in this sample event data set with an average MDC of 11.7 pCi/L. The Fe-55 data are normally distributed around the limiting mean value of -22.8 pCi/L as indicated in Figure 5-10. The limiting mean value is statistically less than zero, based on the t-test. These results are typical of LSC analysis where a significant negative systematic bias in the underlying baseline distribution exists. In the past, we have observed both positive and negative biases with Fe-55 analytical results. This suggests that the analytical laboratory has some difficulty in determining the appropriate analytical blank contribution for Fe-55.

Similar results were obtained for other LSC radionuclides. CYAPCo will continue to statistically evaluate and monitor these data. In the meantime, we will report the data as is in order to evaluate any dose risk associated with groundwater monitoring in a conservative manner.

5Z8.3 Beta and Alpha Emitters via GPC Figure 5-11 is a rank order plot of Sr-90 in water for the June 2004 sampling event. An average and 1-a standard deviation concentration of 0.43 +/- 0.39 pCi/L was observed in the limiting mean baseline data set after removing statistically significant or positive outliers. The control limits are +/- 0.78 pCi/L based on the average 2-a standard deviation of the limiting mean. Results with concentrations greater than 1.1 pCi/L were determined to be statistically different from the underlying background based on outlier testing. It is easy to visually identify the transition from the underlying background 39

data to the statistically significant data in Figure 5-11. Note that 27 of the 32 reported Sr-90 results for this data set were greater than the zero concentration.

The baseline Sr-90 data consisted of 24 data points and were normally distributed around the limiting mean value of 0.43 pCi/L as indicated in Figure 5-12. The baseline limiting mean value was statistically greater than zero based on the t-test. These results are typical of GPC analysis where a positive systematic bias in the underlying baseline distribution exists.

Similar results were obtained for gross alpha and gross beta analyses performed via GPC. In the case of gross alpha and gross beta, the positive trends observed in these analyses, is actually attributed to natural levels of gross alpha and beta radioactivity.

528A HTD Alpha Emitters Figure 5-13 is a rank order plot of Cmii-242 concentrations in groundwater for the June 2004 sampling event. Curium-242 is an alpha emitter with an expected low radionuclide inventory at HNP due to radioactive decay. Curium-242 has a radioactive half-life of 163.2 days and has decayed through greater than 14 half-lives since shutdown. Since less than 0.01% of the shutdown activity or inventory remains, Cm-242 is not expected to be present in detectable quantities in groundwater samples from the HNP.

An average and 1-a standard deviation concentration of 0.004 +/- 0.017 pCi/L was observed in this data set while the average MDC was 0.18 pCi/L. The control limits are

+/- 0.034 pCi/L based on 2-a standard deviations in the analytical blank. Note that the individual 2-sigma error bars generally span the region of the control limits except in the negative regions of the graph. Here the 2-a TPU is underestimated due to the presence of zeros in the analytical counting results. This is characteristic of low-level alpha counting where zero results are sometimes observed (i.e., zero counts observed in the detector region-of-interest) during the finite counting interval.

The baseline data are normally distributed around the limiting mean value of 0.004 pCi/L in Figure 5-14 and the limiting mean value is not statistically different from zero, based on the t-test Low-level counting data are not expected to be normal, around a limiting mean value. This is a characteristic of low-level alpha counting where the expected shape of the limiting mean distribution is Poisson in nature. The Poisson distribution is asymmetric and representative of a distribution that is bounded by zero on the low frequency side. T-test results for low-level counting are only qualitative in nature, since normality is a required condition for this statistical test. CYAPCo will continue to develop statistical tests to evaluate this low-level counting data in the future.

As expected, no significant Cm-242 activity is indicated in this trend plot. These results are typical of low-level alpha isotopic analysis where no analyte is present.

Figure 5-15 is a rank order plot of Am-241 concentrations in groundwater for the June 2004 sampling event Americium-241 is an alpha emitter that has been detected in HNP process streams attributed to failed fuel. An average and 1-a standard deviation concentration of 0.023 +/- 0.049 pCi/L was observed in this data set while the average MDC was 0.23 pCi/L. The control limits are +/- 0.098 pCi/L based on the average 2-a 40

TPU in the analytical blanks. Note that the individual 2-sigma error bars generally span the region of the control limits except in the negative regions of the graph.

The data are normally distributed around the limiting mean value of 0.023 pCi/L in Figure 5-16. This is not expected based on the typical count rates observed via alpha counting as previously discussed. The limiting mean value of 0.023 pCi/L is not statistically greater than zero analyte level based on the t-statistic and 39 (n-1) degrees of freedom. Note that a slight elevation in Am-241 activity is indicated in this trend plot as compared to the Cm-242 trend plot and as 27 of 39 results are greater than zero concentration. No significant positive trends were observed with other alpha isotopic data.

In the past CYAPCo lab vendors have had some minor difficulties with "false positive" detects for Am-241 during the course of performance evaluation (PE) testing. It is important to note that Am-241 is a common alpha-emitting radiotracer used in the radiochemistry lab. Solid-state alpha detectors are subject to recoil contamination after repetitive source and sample analysis. Alpha recoil contamination, which increases the detector background, occurs when fragments from the source or sample are implanted in the detector surface, by the recoil energy imparted on the nucleus of an alpha-emitting atom. Solid-state alpha detector background rates are extremely low, typically on the order of 1 count per 100,000 seconds. Given typical sample analysis parameters and the sensitivity requirements for these analyses, the ability to accurately distinguish sub-pCi/L amounts of Am-241 groundwater from the detector background contribution is non-trivial. These results are typical of low-level alpha isotopic analysis where the underlying baseline distribution is subject to large fluctuations due to the extremely low ambient background count rate.

5.2.8.5 Radiochemical Bias Summary Attached in Table 5-14 is a summary of the percentage of positive results detected at concentrations that were greater than 2-a TPU and near the MDC level. This table provides an indication of the percentage of false positive results as a function of analysis method. Know statistically positive results were removed from these summaries. Only about 3.2% of the gamma isotopic analysis results were greater than the 2-a TPU level, which is just slightly higher than the expected rate of 2.5% if there were no significant gamma emitters present. One would expect a "false positive" rate of 2.5% based on the area under the standard normal distribution around a limiting mean concentration of zero, at the 95% confidence level. These results suggest that there is little bias in the gamma isotopic analytical results at levels near the MDC, and there is little gamma isotopic activity in these samples.

Alpha isotopic results for the March and June 2004 sample events indicated overall positive activity rates of 0%, which also indicates no significant alpha activity present in these samples with minimal bias in the analytical technique at levels near the MDC.

The percentage of HTD beta results determined via LSC and with concentration levels greater than 2-ca TPU ranged from 4.3% to 1.9%. These results were generally normally distributed around a limiting mean concentration in most cases. Only 2 of the 12 LSC 41

analyses indicated limiting mean distributions that were positive. Negative limiting mean distributions were observed for 4 of the 12 LSC analyses Factors that may affect the uncertainty of radiological analyses, and the ability to discern plant-related activity from the natural background activity include; interference from naturally occurring radionuclides due to incomplete radiochemical separation, specificity of radiochemical counting technique, and difficulty in identifying the ambient background or blank contribution. In low-level radiochemical counting, these limitations are imposed by the accurate determination of the systematic and random uncertainty associated with the analytical blank. Generally speaking, gamma isotopic and alpha isotopic analyses are the most specific counting methods with the least amount of systematic bias in the underlying background or blank. GPC and LSC are less specific counting methods and may be subject to systematic and random variability in the underlying blank distribution. CYAPCo will continue to statistically evaluate and trend lab data in order to understand limitations and irregularities in analytical results.

Based upon the work performed during the implementation and development of this Groundwater Monitoring Report for the March and June 2004 quarterly sampling events, the following conclusions and recommendations have been developed for the radiochemical analyses presented in this report:

• Systematic biases were observed in several of the HITD analyses based on statistical and graphical evaluations of the reported analytical data. Negative biases were observed for several radioisotopes analyzed by LSC. The affected analyses included Fe-55, Ni-63 and Tc-99.

• Positive systematic biases were observed in several of the HTD analyses by LSC and GPC. The affected analyses included gross alpha, gross beta, He-3, C-14 and Sr-90.

An overall false positive rate on the order of 1.9% was observed for the LSC analyses results. This is nominally similar to the expected false positive rate of 2.5%, which is a noted overall improvement in the LSC analyses.

• A positive bias was also observed for Co-60 which is a gamma emitter. CYAPCo will continue to statistically evaluate and trend the biases identified within this report.

• Field collected and laboratory completed QA/QC sample results were within acceptable protocol ranges for all analyses.

• External laboratory performance evaluation data was excellent for all gamma emitters and good to average for the alpha and beta HTD analysis. Less than 50% of the false positive test results were in the acceptable or acceptable with warning range.

• Internal laboratory performance evaluation data was excellent for all analyses.

Greater than 98% of the results met the acceptance criteria.

5.3 Data Quality Summary Analysis of radiochemical constituents was performed on unfiltered water samples collected from groundwater monitoring wells at HNP during March and June 2004. In addition, filtered and unfiltered samples were analyzed at several locations to evaluate the presence of radiochemical and boron dissolved species (as observed in the filtered 42

sample results) as well as species associated with suspended particulate in the groundwater (as observed in the unfiltered sample results, which represent both dissolved and suspended c6ntents). Selected groundwater samples were field filtered using 0.45 micrometer in-line filters prior to preservation.

Overall, assessments of QA/QC information indicate that groundwater monitoring data are acceptable for groundwater characterization and monitoring efforts. Groundwater sampling was performed in accordance with sample plans and work processes. No contamination or other sampling-related problems were identified that affected data integrity in the field. Laboratory external performance data was good to excellent for all constituents. MAPEP performance results for false positive testing requires some improvement. Laboratory internal performance data was good to excellent for all constituents but boron, which requires improvement. Measurement of boron and radiochemical constituents in samples collected from HNP met the identified data quality metrics for these two sampling events.

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6 Spatial and Trend Analysis 6.1 Spatial Distribution of SOCs The spatial distribution of detected SOCs (boron, tritium, Sr-90) have been mapped for the unconsolidated, shallow bedrock, and deep bedrock deposits hydrostratigraphic units for the March and June 2004 sampling events, and are summarized below. The shallow bedrock hydrostratigraphic unit is defined as bedrock within 10 feet of the unconsolidated/bedrock boundary. Bedrock greater than 10 feet below the bedrock surface is considered deep bedrock.

There is uncertainty in mapping groundwater flow and contaminant distribution in fractured rock. The maps of contaminants in shallow and deep bedrock, and the text discussing spatial distribution is intended to show general distribution of contaminants; actual flow through the fractured rock may vary significantly from that depicted and discussed. The inferred distribution of SOCs represent interpretations of site conditions.

6.1.1 Spatial Distribution of SOCs from March 2004 Groundwater Sampling The concentrations of boron, tritium, and,mmSr-90, for the March 2004 sampling results for the industrial area and peninsula area are displayed on Figures 6-1 and 6-2. A discussion of the distribution of the SOCs in each hydrostratigraphic unit is presented in the following sections.

6.1.1.1 Boron Boron is detected in all three of the hydrostratigraphic units at concentrations ranging from non-detect up to 735 1jg/L. There is no MCL established for boron. A discussion of the boron distribution in groundwater for the three hydrostratigraphic units is presented in the following sections.

Unconsolidated deposits hydrostratigraphic unit:

In the unconsolidated deposits (Figure 6-3), boron concentrations appear highest around the southwest and southern perimeter of the RCB in MW-105S (735 jig/L) and MW-106S (670 gg/L), with plume concentration decreasing to the'south and southeast. As discussed in Section 2, the discharge tunnel is located south of the RCB and forms a barrier for flow in the unconsolidated deposits. In the area of the discharge tunnel, groundwater flow in the unconsolidated unit is redirected to the southeast where the tunnel base is no longer on/in bedrock. East of the discharge tunnel the unconsolidated unit thickens considerably, and groundwater flow in the unconsolidated unit continues due south toward the Connecticut River (Figure 6-3). The effects of the discharge tunnel are dearly reflected in the boron distribution as the boron plume wraps around the tunnel and continues to the south and southeast towards the Connecticut River (Figure 6-3).

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A second, lower concentration plume occurs in the western portion of the industrial area. Elevated boron concentrations are observed in MW-100S (212 jig/L), MW-104S (299 gg/L), MW-124 (228 gg/L), and MW-109S (254 pg/L). Elevated boron was observed in this portion of the site in previous studies. These monitoring wells form a plume of elevated boron south from MW-1OOS south towards the Connecticut River.

This second boron plume is not associated with tritium or other radionuclides suggesting a source other than borated water from the power plant process.

Shallow bedrock hydrostratigraphic unit:

In the shallow bedrock boron is detected in both the western and eastern portions of the industrial area. Elevated boron is detected in MW-109D (210 g1g/L) and MW-123S (107 gg/L) located in the eastern portion of the industrial area. Boron is also detected in a plume extending south from MW-103S (85.7 [ig/L), past MW-107D (38 pg/L), and on to MW-11OD (179 [tg/L) (Figure 6-4). Both areas of detected boron appear to flow from north to south towards the Connecticut River (Figure 6-4).

The highest concentrations of boron in both plumes occurs in the downgradient portion of the plume and higher boron concentrations have been historically observed in the upgradient wells associated with both plumes. This suggests that a slug of elevated boron has historically migrated through the industrial area towards the Connecticut River.

Deep bedrock hydrostratigraphic unit One area of elevated boron occurs within the bedrock hydrostatic unit (Figure 6-5).

Boron is detected in several monitoring wells in the vicinity of the RCB including MW-122D (224 jig/L), MW-102D (113 jig/L and MW-103D (90.9 Itg/L). The remainder of the deep bedrock boron detections are below 75 [tg/L and may represent background conditions.

6.1.1.2 Tritium Tritium is detected in all three of the hydrostratigraphic units at concentrations ranging from non-detect up to 12,000 pCi/L. All detections in all three hydrostratigraphic units are under the C4concentration for tritium of 20,OOOpCi/L.

Unconsolidated deposits hydrostratigraphic unit In the unconsolidated deposits (Figure 6-6), tritium was detected above activity concentrations of 1,000 pCi/L in two locations. One of these locations exists in a fairly small area southwest of the RCB in MW-105S (5,520 pCi/L). This elevated tritium appears to extend southwest along the probable path of groundwater flow around the northwest end of the discharge tunnel including MW-124 (1,530 pCi/L), as the water level in MW-124 is significantly less than that measured in MW-105S (Figure 6-6).

The second area with concentrations above 1,000 pCi/L occurs form the northeast side of the RBC southeastwards towards the discharge canal (Figure 6-6). This plume of elevated tritium includes monitoring wells MW-115S (5,740 pCi/L), MW-114S (1,350 pCi/L), MW-125 (2,350 pCi/L) and MW-110S (2,050 pCi/L) and is interpreted to flow from the RCB, past the discharge canal, and towards the Connecticut River.

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Shallow bedrock hydrostratigraphic unit In the shallow bedrock (Figure 6-7), tritium is detected to the north of the RCB in MW-103S (1,090 pCi/L) and northeast of the RCB in MW-102S (6,740 pCi/L). based on the groundwater contour maps for the shallow bedrock, it appears that groundwater flows from the east side of the RCB, and then continues south toward the Connecticut River, passing through the area of MW-11OD (5,890 pCi/L) Figures 6-7, 2-6 and 2-7).

A second distinct area of elevated tritium in the shallow bedrock occurs at MW-109D where 4550 pCi/L is detected (Figure 6-7).

Deep bedrock hydrostratigraphic unit In the deep bedrock (Figure 6-8), tritium is detected in the vicinity of the RCB, and appears to be centered around the north and east edge in MW-103D (12,000 pCi/L) and MW-102D (4,940 pCi/L). There are no deep bedrock monitoring wells south of the-eastern edge of the RCB to determine if the deep bedrock tritium is moving south of its current location, but the effects of the mat sump most likely limit the southward migration (Figures 2-8 and 2-9). The general groundwater flow direction in the deep bedrock is to the south and southeast towards the Connecticut River as tidal effects are present in the deep bedrock monitoring wells. The deep bedrock plume is bounded on the south of the RCB by monitoring well MW-106D (1,110 pCi/L).

6.1.1.3 Strontium-90 Sr-90 is detected in all three of the hydrostratigraphic units at concentrations ranging from non-detect up to 91.8 pCi/L. The C4 concentration for Sr-90 is 8 pCi/L. One well (MW-105S) exceeds that concentration at 91.8 pCi/L.

Unconsolidated deposits hydrostratigraphic unit In the unconsolidated deposits hydrostratigraphic unit the highest Sr-90 is detected in MW-105S (91.8 pCi/L) located adjacent to the southwest side of the RCB (Figure 6-9).

Additional detected Sr-90 occurs in MW-114S (3.92 pCi/L), MW-115S (1.64 pCi/L), and MW-106S (1.21 pCi/L). These three monitoring wells are located adjacent to the northeast and southeast sides of the RCB, and along with MW-105S form a plume of Sr-90 that flows around the discharge tunnel the south towards MW-125 (3.15 pCi/L)

(Figure 6-9). Based on the groundwater flow maps developed for the unconsolidated unit, it appears that the Sr-90 is migrating south toward the Connecticut River (Figures 2-4 and 2-5).

Shallow bedrock hydrostratigraphic unit:

In the shallow bedrock Sr-90 is detected in three isolated monitoring wells, MW-103S (2.27 pCi/L) just north of the RCB, MW-123 (0.866 pCi/L), west-of B Switchgear.

building, and in MW-11OD (0.657 pCi/L) located south of the discharge canal (Figure 6-10). Based on the limited data available in the vicinity of the RCB and the PAB in this hydrostratigraphic unit and the non-detect values in all of the other monitoring wells, no distinct plume can be mapped in the shallow bedrock hydrostratigraphic unit.

46.

Deep bedrock hydrostratigraphic unit:

In the deep bedrock hydrostratigraphic unit Sr-90 was detected only in monitoring wells MW-122D (0.552 pCi/L) east of the RCB. All other deep bedrock monitoring wells had non-detect Sr-90 concentrations (Figure 6-11).

6.1.2 Spatial Distribution of SOCs from June 2004 Groundwater Sampling The concentrations of boron, tritium, and Sr-90 for the June 2004 sampling results for the industrial area, EOF, parking lot, and peninsula area are displayed on Figures 6-12, 6-13, and 6-14. A discussion of the distribution of the SOCs in each hydrostratigraphic unit is presented in the following sections.

6.1.2.1 Boron Boron is detected in all three of the hydrostratigraphic units at concentrations ranging from 10.4 pg/L up to 1260 jig/L. There is no MCL established for boron. A discussion of boron in the three hydrostratigraphic units follows.

Unconsolidated deposits hydrostratigraphic unit:

In the unconsolidated deposits (Figure 6-15), boron concentrations appear highest around the perimeter of the RCB. The highest boron concentration occurs in MW-114S (1,260 jtg/L) located adjacent to the northeastern portion of the RCB. Elevated boron concentrations also occur in MW-105S (484 jig/L) and MW-106-S (490.tg/L) south of the RCB. Consistent with the groundwater flow contours in the unconsolidated unit, a plume of boron occurs the south and east of the RBC with concentration decreasing to the south (Figures 2-10, 2-11 and 6-15). The discharge tunnel forms a barrier for flow in the unconsolidated deposits, so flow is redirected south east past where the tunnel base is no longer on/in bedrock, and then continues due south toward the Connecticut River.

The boron distribution in the southeastern, downgradient portion of the plume is characterized by MW-125 (445 pg/L) and MW-l1S (291.pg/L).

A second, lower concentration plume occurs in the western portion of the industrial area. Elevated boron concentrations are observed MW-104S (274 jig/L), MW-124 (225 pg/L), and MW-109S (124 pg/L). These monitoring wells form a plume of elevated boron that flows south from MW-104S south towards the Connecticut River, consistent with mapped groundwater flow in the unconsolidated unit (Figures 6-15,2-10 and 2-11).

This second boron plume is not associated with tritium or other radionuclides suggesting a source other than borated water from the power plant process.

Shallow bedrock hydrostratigraphic unit:

The distribution of boron in the shallow bedrock unit defined by the June 2004 data is similar to the distribution mapped for the March 2004 results. Two linear areas of elevated boron occur in the eastern and western portions of the industrial area (Figure 6-16). Boron concentrations are detected in MW-103S (165 pg/L) and along a linear plume running from just east of the RCB near MW-102S (92.1ipg/L), south through MW-llOD 47

(236 iig/L). A second, lower concentration location area occurs at MW-lOS (68.6p1g/L),

continuing south through MW-123S (90 jLg/L) and MW-120D (191 ptg/L). Based on the groundwater flow maps interpreted for the shallow bedrock, both plumes appear to be flowing in the general direction of the Connecticut River (Figures 6-16, 2-12 and 2-13).

Deep bedrock hydrostratigraphic unit:

Boron concentrations in the deep bedrock are highest in MW-122D (223 pg/L), declining north and south of that location (Figure 6-17). All other detections are below 100 pg/L.

6.1.2 Tritium All detections in all three hydrostratigraphic units are below the C4 concentration for tritium of 20,000 pCi/L. Elevated tritium concentrations are observed in all three hydrostratigraphic units, with the highest concentration observed in the unconsolidated unit.

Unconsolidated deposits hydrostratigraphic unit:

Similar to the tritium distribution of tritium mapped from the March 2004 results, detections of tritium appear to be distributed primarily in two locations (Figure 6-20).

The first location appears just east of the RCB at MW-114S (6,730 pCi/L) and forms a plume that flows south, consistent with the mapped groundwater contours, through MW-125 (2,170 pCi/L) and MW-11S (1,010 pCi/L) toward the Connecticut River (Figures 6-18, 2-10, and 2-11).

The second area occurs at MW-105S (3,35OpCi/L). Elevated tritium levels are also observed at MW-124 (1,770 pCi/L), and based on the lower groundwater level in MW-124, are interpreted to flow from the area of MW-105S between the primary au)dliary building and the northwest end of the discharge tunnel (Figures 6-20,2-10, and 2-11).

There remains uncertainty regarding actual connection of inferred SOC plumes in this area.

Shallow bedrock hydrostratigraphic unit.

In the shallow bedrock detections of tritium appear to be distributed primarily in two locations (Figure 6-21). The first appears similar to the eastern distribution in the unconsolidated hydrostratigraphic unit identified in the March 2004 results (Figures6-7 and 6-20). Elevated tritium concentrations are observed north and east of the RCB in MW-103S (5,300 pCi/L) and MW-102S (5,740 pCi/L), and continuing on south through MW-11OD (8,300 pCi/L), toward the Connecticut River, consistent with the mapped groundwater contours for the shallow bedrock (Figures 2-12 and 2-13):

The second location of elevated tritium is detected in MW-109D (3,140 pCi/L), and from there along the mapped groundwater flow direction south toward the Connecticut River (Figures 2-12 and 2-13).

Deep bedrock hydrostratigraphic unit:

Tritium in the deep bedrock stratigraphic unit is focused in the area of the RCB. The highest concentrations occur north of the RCB in MW-103D (6,530 pCi/L) and MW-102D (4,690 pCi/L). Lower tritium concentrations occur in MW-106D (1,520 pCi/L) south of 48

the RCB. The lack of deep bedrock monitoring wells further to the south do not allow the plume to be further characterized in that area.

6.1.2.3 Strontium 90 Sr-90 is primarily detected in the unconsolidated and shallow bedrock hydrostratigraphic units with concentrations ranging from non-detect to 16.2 pCi/L.

The C4 concentration for Sr-90 is 8 pCi/L, which is exceeded in MW-105S. The Sr-90 distribution in the three hydrostratigraphic units is discussed in the following sections.

Unconsolidated deposits hydrostratigraphic unit.-

The highest Sr-90 concentrations in the unconsolidated unit are located adjacent to and south of the RCB (Figure 6-21). The highest Sr-90 concentration occurs in MW-105S (162 pCi/L) with 3.7 pCi/L detected in MW-106S located south of the RCB (Figure 6-21). As groundwater cannot flow south of the discharge tunnel, Sr-90-contaminated groundwater appears to flow around both the east and west ends of the tunnel and is detected in MW-124 (1.33 pCi/L) and MW-125 (1.78 pCi/1). Low Sr-90 concentrations are observed in MW-109S (0.801 pCi/L) and MW-11OS (0.689 pCi/L), both located downgradient of the higher concentrations (Figures 6-21,2-10, and 2-11).

Although MW-105S had the highest Sr-90 concentration in the June sampling event, MW-105 exhibited the lowest concentration of Sr-90 observed since monitoring for that.

constituent began in 1992 (Appendix H). While the cause of this relatively large decline in concentration is not clearly identified, a number of conditions may have contributed to the decline. These possible explanations are discussed below:

• MW-105 has exhibited measurable turbidity during all previous sample events. The well was redeveloped prior to the June 2004 sampling event. Subsequent radiochemical analysis of a sample of the sediment removed during redevelopment indicated measurable Sr-90 in the sediment. Contaminated sediment in the well may have contributed the historical elevated Sr-90 concentration causing a localized area of elevated groundwater.

• The former contaminated wastewater handling activities that were conducted in the tank farm were discontinued within the past two years and the primary source material was removed. This remedial activity was performed inside the containment tent constructed over the tank farm. Both the removal of the source of contamination and the placement of the tent over the residual contaminated soil, thus eliminating local recharge of precipitation infiltrating through the contaminated soil, may have reduced the Sr-90 contribution to the groundwater.

• Active dewatering was initiated early in 2004. This activity lowered the water level in the tank farm and in the vicinity of MW-105 and may have reduced continuing contamination contribution from subsurface soils to the groundwater.

Shallow bedrock hydrostratigraphic unit:

Sr-90 was detected in only one monitoring well in the shallow bedrock hydrostratigraphic unit. Monitoring well MW-103S located north of the RCB had a concentration of 1.34 pCi/L (Figure 6-22). All of the other monitoring wells were non-detect for Sr-90.

.49

Deep bedrock hydrostrntigraphic unit In the deep bedrock Sr-90 was detected in the vicinity of the RCB in MW-122D (3.29 pCi/L), 102S (0.928 pCi/L), MW-105D (1.11 pCi/L), and MW-103D (1.26 pCi/L) (Figure 6-23). All of the other deep bedrock monitoring wells were non-detect for Sr-90. The detection of Sr-90 in MW-122D is greater than recent monitoring results (Appendix H).

Evaluation of the monitoring well indicates that the well cap was not secured, indicating the potential for sample bias.

6.2 Trend Analysis of SOCs 6.2.1 Boron Trend Analysis There has been a general decrease in the observed maximum boron concentration at HNP since March 1999. Boron concentrations have generally fluctuated over the time-frame of the GWMP without any discernable temporal or spatial trends. The boron quarterly monitoring analytical results from March 1999 through June 2004 are summarized in Table 4-1. Time series plots of the boron concentrations from March 1999 to June 2004 are provided in Appendix F.

The higher boron concentrations have generally been detected in the shallow wells, typically those wells screened in the unconsolidated deposits hydrostratigraphic unit.

Boron levels in deep bedrock wells have typically been relatively low compared to wells completed in shallower intervals, probably reflective of background concentrations.

This generalization is well illustrated by the time series plot of well pair MW100S and 100D. Boron concentrations that have fluctuated greatly in MW100S, screened in the unconsolidated deposits, ranging as high as 1,145 pg/L as recently as June 2003, to a stable trend of non-detections exhibited in MW-1OOD, a deep bedrock well. Similar trends are also shown in the MW105S/D andMW106S/D well pairs, both of which have shown greatly elevated boron concentrations in the shallow unconsolidated deposits wells and low boron levels in the deep bedrock wells probably near background concentrations.

Attached in Figure 6-24 is a box plot for Boron concentrations as a function of time ranging from March 1999, through June 2004. Box plots provide a mechanism to graphically compare 2 or more sets of data, in this case, temporal or seasonal groundwater monitoring results from multiple quarterly sampling events. In particular,.

trends with respect to the median, extreme values and data dispersion over time are visually evident. The median value provides an unbiased central tendency of the data that is not affected by extreme outliers. The position of the median value in the vertical box provides information regarding the symmetry of the inter-quartile range when viewed on a linear scale. The inter-quartile range describes the spread of the central 50%

of the data. The length of the vertical boxes shows the extent of the inter-quartile range.

The length of the vertical lines or whiskers shows the overall extent of the data above and below the inter-quartile range. We have selected a log concentration scale since the detectable concentrations ranged over 2 or more orders of magnitude.

50

The box plot displays a quartilie summary of quarterly sample event data with some key statistics. The quarterly sample event results are sorted in increasing numerical order and divided into 2 groups at the median or second quartile (Q2). The median of the lower group is the first quartile (Q.) and the median of the upper group is the third quartile (Q3). The difference between Q3 and Q( is the inter-quartile range and is represented by the central vertical box or rectangle in the box plot diagram. The horizontal line dividing the central vertical box is the second quartile (Q2) or median value of the data set. The two lines extending out from the center box are the whiskers and the end points in this case represent the minimum or zero quartile (Qo) and maximum or fourth quartile (Q4) values.

The plotted values in Figure 6-24 display results for all wells sampled during the sampling event with concentrations greater than the method detection limit (MDL).

There has been a general decrease in the observed maximum boron concentration since March 1999. Median results have fluctuated from a low of about 45 pg/L in June 2001 to a high of 188 pg/L during September of 2002 with no apparent temporal or seasonal trend.

6.2.2 Gross Alpha Trend Analysis Gross alpha concentrations for the past 10 sample events for unconsolidated, shallow and deep bedrock wells are plotted in Figures 6-25 through 6-27. Higher gross alpha levels were generally detected in the deeper wells completed in bedrock during these sampling events (Figures 6-26 and 6-27). The source of most of the activity is erosion of naturally occurring alpha-emitting nuclides that are likely present in the granitic gneiss bedrock. Natural levels of gross alpha activity can range as high as a few hundred pCi/L, when special sampling techniques designed to capture the volatile and short-lived natural alpha emitters are observed. Although it is possible that plant-related radionuclides contribute to some of the observed gross alpha activity, it is not probable since alpha isotopic analysis generally results in non-detects with nominal detection sensitivity on the order of 0.3 pCi/L or less.

Figure 6-28 is a box plot for site-wide gross alpha concentrations as a function of time ranging from December 2001, through June 2004. Plotted values in this case represent statistically significant results with concentrations greater than the 2-a TPU. The maximum gross alpha concentration has ranged from 7.8 to 28.8 pC/L since December of 2001. Median results have fluctuated from a low of about 1.3 pCi/L to a high of 5.1 pCi/L. There were no apparent temporal or seasonal trends.

6.2.3 Gross Beta Gross beta results for the two quarterly sampling events are summarized in Table 4-2.

Gross beta results ranged from 1.6 to 490 pCi/L. The CI Public Drinking Water Quality Standard screening level for gross beta radioactivity is 50 pCi/L though natural levels may range as high as a few hundred pCi/L.

51

As shown on Table 4-2, gross beta activity at high levels roughly correlates with Sr-90 (a beta emitter) data, in that the highest concentration of Sr-90 is also found in MW-105S.

Another beta emitter which contributes to gross beta activity is Cs-137 and has been detected in MW-102D, MW-103S and MW-115S. Table 4-2 shows that groundwater from these locations also has relatively high concentrations of gross beta activity.

Gross beta concentrations from the past 10 sample events for unconsolidated, shallow and deep bedrock wells are plotted in Figures 6-29 through 6-31. With the exception of wells MW-103S, MW-105S, MW-106S and MW-102D which have measured levels of Sr-90 and Cs-137, gross beta results are all less than the CI Public Drinking Water Quality Standard screening level of 50 pCi/L.

Figure 6-32 is a box plot for site-wide gross beta concentration as a function of time ranging from December 2001, through June 2004. The maximum gross beta concentration has ranged from 142 to 490 pC/L, since December of 2001. Median results have fluctuated from a low of about 5.4 pCi/L, to a high of 10.0 pCi/L. There are no apparent temporal trends associated with gross beta results. There does appear to be a seasonal trend associated with the maximum gross beta results. The maximum gross beta levels observed to date are at MW-105S, and these levels tend to coincide with sampling events associated with peak groundwater elevation including March and June time periods.

6.2.4 Tritium Trend Analysis There has been a general decrease in tritium activity concentrations at HNP since the quarterly GWMP sampling was implemented in March 1999. A summary of tritium results from the GWMP is provided in Table 4-3. The higher tritium activity concentrations have typically been exhibited in the bedrock wells, notably deep bedrock wells MW-102D and MW-103D, and shallow bedrock well MW-110D. MW-105S, a well screened in the unconsolidated deposits hydrostratigraphic unit, has historically displayed the highest tritium activity concentrations at the facility. None of these wells detected tritium above the EPA MCL of 20,000 pCi/L during the March and June 2004 sampling events. Time series plots showing tritiumn activity concentrations from the GWMP quarterly sampling events are shown in Appendix G.

Historically, the highest tritium activity concentration observed at MW-102D was 28,630 pCi/L during the June 2003 sample event (see Figure 6-33). Tritium results for MW-102D ranged from 4,940 to 4,690 pCi/L, in March and June 2004, respectively, suggesting a leveling off in the concentrations at this well. MW-102D, a deep bedrock well, exhibited fairly stable tritium concentrations in the 20,000-pCi/L range over the sampling events prior to December 2001.

Since December 2001, tritium levels in MW-103D have ranged from 8,100 pCi/L to 12,900 pCi/L, suggesting a substantial short-term decrease in concentrations in ftiis well (see Figure 6-34). Analytical results for MW-103D ranged from 12,000 pCi/L during the March 2004 event to 6,530 pCi/L during the June 2004 event.

Tritium levels in well MW-11OD have decreased substantially from the 27,630 pCi/L detected when quarterly monitoring commenced in March 1999. In December 2002, 52

tritium levels decreased to 11,100 pCi/L (see Figure 6-35). Results have ranged from 5,890 pCi/L in March 2004, to 8,300 pCi/L, during the June 2004 sampling event.

The highest tritium concentration recorded to date was 138,700 pCi/L at well MW-105S during the March 1999 sampling event. There has been a significant downward trend in tritium concentrations at this well with results ranging from 5,520 to 3,280 pCi/L during the March and June 2004 sampling events (see Figure 6-36).

There has been a significant upward trend in tritium concentrations at MW-114S with results ranging from 1,350 to 6,730 pCi/L during the March and June 2004 sampling events (see Figure 6-37).

Tritium concentrations from the past 10 sample events for unconsolidated, shallow and deep bedrock wells are plotted in Figures 6-38 through 6-40. With the exception of well MW-102D, all H-3 results during these sample events were less than the EPA MCL of 20,000 pCi/L.

Figure 6-41 is a box plot for site-wide H-3 concentrations as a function of time ranging from March 1999, through June 2004. Maximum H-3 concentrations have ranged from 13,900 to 28,630 pCi/L since September of 1999. Median results from have fluctuated from a low of about 1170 pCi/L to a high of 4430 pCi/L during this same period. There were no apparent seasonal trends in the median results. An overall downward trend in the site-wide median H-3 concentrations has been observed since March 1999.

6.2.5 Strontium-90 Trend Analysis Tables 4-2 summarizes Sr-90 concentrations from the quarterly sampling events.

Historically, monitoring well MW-105S has exhibited the highest concentration of Sr-90 (see Figure 6-42). Strontium-90 activity concentrations in MW-105S have fluctuated over the quarterly sampling events with March 2004 levels reported at 91.8 pCi/L, above the C4 concentration of 8 pCi/L. Elevated Sr-90 concentrations have also been noted at MW-106S (see Figure 6-43). Other wells where Sr-90 concentrations greater than the CRDL of 2 pCi/L included MW-103S and MW-104S (see Figures 6-44 and 6-45).

Strontium-90 concentrations from the past 10 sample events for unconsolidated, shallow and deep bedrock wells are plotted in Figures 6-46 through 6-49. With the exception of well MW-103S, all Sr-90 results for shallow bedrock wells were less than the EPA MCL of 8.0 pCi/L. All results for deep bedrock wells were less than the CRDL of 2 pCi/L and no result to date has exceeded this level.

Figure 6-50 presents a box plot for site-wide Sr-90 concentration as a function of time ranging from December 2001, through June 2004. The maximum Sr-90 concentration has ranged from 69.7 to 197 pC/L since December of 2001. Median results have fluctuated from a low of about 0.8 pCi/L to a high of 4.6 pCi/L. There were no apparent temporal or seasonal trends in the median values. There appears to be a seasonal trend in the highest values which all occur inMW-105S. These maximum values levels tend to 53

coincide with March and June sampling events, which are typically characterized by peak groundwater elevation levels.

6.2.6 Cesium-137 Trend Analysis Cesium-137 was'detected at statistically significant concentrations and greater than the MDC during the March and June 2004 sampling events. Table 4-2 summarizes Cs-137 analytical results in all wells since December 2001. Prior to the March and June 2004 sampling events, Cs-137 has been consistently identified in groundwater at location MW-103S between a minimum of 8.39 pCi/L and a maximum of 87.6 pCi/L (Figure 6-51). MW-103S is the shallow monitoring well in the cluster located in the vicinity of the former RWST. Cesium-137 has also been consistently detected at two additional monitoring wells, MW-115S and MW-102D. Cesium-137 has been detected in MW-115S in concentrations ranging from 1.6 to 7.59 pCi/L (Figure 6-52). Cesium-137 concentrations have ranged from 2.0 to 12.7 pCi/L in MW-102D (Figure 6-53).

Cesium-137 concentrations from the past 10 sample events for unconsolidated, shallow and deep bedrock wells are plotted in Figures 6-54 through 6-56. With the exception of well MW-103S, all Cs-137 results during these sample events were less than the CRDL of 15 pCi/L. The EPA MCL for Cs-137 is 200 pCi/L and no result to date has exceeded this level. Combined time series plots for Sr-90 and Cs-137 are provided in Appendix H.

6.2.7 Alpha Isotopic Analyses Americium-241 concentrations from the past 10 sample events for unconsolidated, shallow and deep bedrock wells are plotted in Figures 6-57 through 6-59. With the exception of well MW-103D, all Am-241 results during these sample events were less than the CRDL of 0.5 pG/L. The EPA MCL for alpha emitters is 15 pCi/L and no result to date has exceeded this level.

6.3 Linear Regression Analysis 6.3.1 Sr/Y-90 + Cs-137 vs Gross Beta Figure 6-60 is a correlation plot of gross beta activity versus total Sr/Y-90 and Cs-137 concentration. Only sample results with detectable Sr-90 or Cs-137 were used in this comparison. Yttrium-90 (Y-90) is the radioactive decay product of Sr-90. Since the half-life of Sr-90 is significantly longer than Y-90, secular equilibrium is observed where both nuclides are characterized by the same concentration levels and the total concentration, denoted as Sr/Y-90, is doubled. A slope of 0.89 with a positive correlation coefficient (R) of 0.964 was observed (see Figure 6-60). The squared correlation term (R2) was 0.929. These results suggest that Sr-90 and/or Cs-137 comprise at least 93% of the gross beta response at higher levels (i.e. greater than 25 pCi/L gross beta activity) and can be used to obtain screening or reasonable estimates of total Sr/Y-90 and Cs-137 in groundwater.

54

7 Conclusions and Recommendations 7.1 Groundwater Quality Status The GWMP at the HNP provides the framework for data collection, quality assurance, and reporting groundwater quality status at the facility. Analytical results from the quarterly sampling program implemented at the plant provide the data for comparing to standards, regulatory limits, and developing metrics for evaluating overall groundwater quality and potentially, plume status at the HNP.

Groundwater contamination by plant-related SOCs has been observed in all three aquifer units currently described at the facility. The general configuration of contaminant plumes extend from the area immediately upgradient of the reactor containment building to the Connecticut River. The observed groundwater contamination at the plant appears to have originated from unplanned releases of contaminated process and waste waters within the general vicinity of the reactor containment building, primary auxiliary building, and other facilities immediately surrounding the reactor containment building.

Tritium, Sr-90, and boron account for the majority of the observed contamination with less-frequent detections of Cs-137. Tritium, boron, and Sr-90 are broadly distributed across the HNP industrial area. Although plant-related tritium concentrations in groundwater have declined substantially below the MCL in recent years, localized areas of other constituents (e.g., Sr-90) have remained relatively elevated. Strontium-90 concentrations in localized areas between the containment building and primary auxiliary building, as exemplified by the observed concentration of Sr-90 in well MW-105S, continues to exceed drinking water standards. Although the Sr-90 concentration currently exceeds the drinking water standard of 8 pCi/L, the concentration measured in the June 2004 sampling round (16.2 pCi/L) has decreased significantly from that measures in previous sampling rounds (164 pCi/L to 197 pCi/L); The observed decrease of Sr-90 in MW-105S is most likely related to redevelopment of the monitoring well and remedial/ dewatering activities upgradient of the monitoring well. Overall, groundwater contamination has declined substantially in the industrial area of the HNP

-since quarterly sampling began in 1999 (Appendices F through G).

7.2 Recommendations for Subsequent Groundwater Monitoring Sampling Events Based on the review of the results of the March 2004 and June 2004 quarterly sampling and observed long-term trends in some wells, several recommendations concerning subsequent groundwater monitoring sampling events are suggested in this section. The recommended analytical suite for the upcoming September 2004 GWMP quarterly.

sampling event should be the same as the one implemented for June 2004, with 55

geochemical parameters sampled and analyzed to compare to previous results.

Collecting filtered and unfiltered samples, however, is not necessary based on the data reduction effort and evaluation of analytical results performed in previous reports.

Unfiltered groundwater samples should be collected from all of the wells in the industrial area and analyzed for all constituents during the September 2004 quarterly sampling event. Otherwise, the wells sampled should stay the same as previous sampling rounds.

Several additional monitoring well locations are suggested for addition to the GWMP based on the evaluation of groundwater quality and plume status performed as part of this report. These include the following

• Background wells upgradient of the industrial area and parking lot. The MW-100 well pair appears to have been historically affected by boron from some undefined source.

A well completed in the unconsolidated formation near the northwest end of the discharge tunnel.

56

8 References CY-ISC-SOW-2003 EML-608 EML-611 EML-613 EML-615 EML-617 EML-618 EML-621 ERA RAD-49 ERA RAD-50 ERA RAD-51 ERA RAD-52 ERA RAD-53 ERA RAD-54 Statement of Work for Environmental, Bioassay and Waste Characterization Analytical Services, Revision 0, August 27,2003 Semi-Annual Report of the Department of Energy, Office of Environmental Management, Quality Assessment Program (QAP 52), June 2000 Semi-Annual Report of the Department of Energy, Office of Environmental Management, Quality Assessment Program (QAP 53), December 2000 Semi-Annual Report of the Department of Energy, Office of Environmental Management, Quality Assessment Program (QAP 54), June 2001 Semi-Annual Report of the Department of Energy, Office of Environmental Management, Quality Assessment Program (QAP 55), December 2001 Semi-Annual Report of the Department of Energy, Office of Environmental Management, Quality Assessment Program (QAP 56), June 2002 Semi-Annual Report of the Department of Energy, Office of Environmental Management, Quality Assessment Program (QAP 57), December 2002 Semi-Annual Report of the Department of Energy, Office of Environmental Management, Quality Assessment Program (QAP 58), June 2004 Semi-Annual Report of the Department of Energy, Office of Environmental Management, Quality Assessment Program (QAP 59), December 2003 Semi-Annual Report of the Department of Energy, Office of Environmental Management, Quality Assessment Program (QAP 60), June 2004 ERA's RadChemm Proficiency Testing Study RAD-49, July 25, 2002 ERA's RadChemTm Proficiency Testing Study RAD-50, November 8,2002 ERA's RadChem.MTProficiency Testing Study RAD-51, January 23,2003 ERA's RadChemTMProficiency Testing Study RAD-52, April 16, 2003 ERA's RadChemTmProficiency Testing Study RAD-53, July 24, 2003 ERA's RadChemTM Proficiency Testing Study RAD-54 57

ERA RAD-55 ERA RAD-57 GMP-QAPP 2004 GMR 1999 GW WPIR 2001 HIWP 2002 LTP 2002 MAPEP-99-S6 MAPEP-00-S7 MAPEP-00-S8 MAPEP-00-S9 MAPEP-00-SlO MAPEP-99-W7 MAPEP-00-W8 MAPEP-00-W9 MAPEP-01-W10 MAPEP-03-Wll NSWPT 1998 RPM 5.3-0 RPM 5.3-1 RPM 5.3-2 RPM 5.3-3 SEP-0304 SEP-0604 GELQAP 2003 ERA's RadChemTM Proficiency Testing Study RAD-55 ERA's RadChemn{Proficiency Testing Study RAD-57 Groundwater Monitoring Program Quality Assurance Project Plan, Revision 1, 2004 Groundwater Monitoring Report, Malcolm Pirnie, September 1999 Groundwater Sample Collection Work Plan and Inspection Record; WP&IR # 24265-000-GEN-5000-00067-000, 12/06/2001 Phase II Hydrogeologic Investigation Work Plan, May 2002 Haddam Neck Plant - License Termination Plan (LTP), Rev. la, 2002 Mixed Analyte Performance Evaluation Program - Soil Sample Participating Laboratory Report, 2/8/2000 Mixed Analyte Performance Evaluation Program - Soil Sample Performance Report, 1/29/2001 Mixed Analyte Performance Evaluation Program - Soil Sample Performance Report, 8/8/2002 Mixed Analyte Performance Evaluation Program - Soil Sample Preliminary Report, 12/5/2002 Mixed Analyte Performance Evaluation Program - Soil Sample Preliminary Report, 12/2003 Mixed Analyte Performance Evaluation Program - Water Sample Performance Report, 7/6/2000 Mixed Analyte Performance Evaluation Program - Water Sample Performance Report, 5/8/2002 Mixed Analyte Performance Evaluation Program - Water Sample Performance Report, 2/11/2003 Mixed Analyte Performance Evaluation Program - Water Sample Performance Report Mixed Analyte Performance Evaluation Program - Water Sample Performance Report National Standards for Water Proficiency Testing Studies Criteria Document, USEPA December 30,1998 Groundwater Monitoring Program, Revision 0, September 2002 Groundwater Level Measurement and Sample Collection in MonitoringWells, Revision CY-001, March 2004 Monitoring Well Drilling and Completion, June 2003 Groundwater Sampling Event Planning and Data Management, June 2003 Sample Event Plan for March 2004 Sample Event Plan for June 2004 GEL Quality Assurance Plan, Revision 15, June 2003 58

9 Definitions C 4 Concentration (Q) - The concentration level for a single analyte that will result in a 4-mrem per year total effective dose equivalent (TEDE) based on target organ dose methodology.

Contract Required Detection Limit (CRDL) - Analysis sensitivity requirements required by contract or SOW. Compliance is determined by comparison with sample specific MDCs or MDLs.

False Negative Rate (3, p*) - The rate at which the statistical procedure does not indicate possible contamination, when contamination is present at some level (P denotes one sample and one constituent, P* denotes multiple samples and one constituent).

False Positive Rate (a, a*) - The rate at which the statistical procedure indicates possible contamination, when contamination is not present (a denotes one sample and one constituent, a* denotes multiple samples and one constituent).

Freshet-A rapidly rising flood of minor severity and short duration, attributed to heavy rains or rapidly melting snow.

Instrument Detection Limit (IDL) - The level at which a measurement can be differentiated from background with some degree of confidence. Computed from the counting error associated with the instrument background or blank counting conditions usually expressed in terms of counts or count rate.

Lab Control Sample (LCS) - A sample prepared by adding a known amount of target analyte to deionized distilled water. Used to assess the method accuracy and long-term analytical precision.

Lower Limit of Detection (LLD) - The level at which a measurement can be differentiated from background with some degree of confidence. Computed from the counting error associated with the analytical blank counting conditions usually expressed in terms of-counts or count rate.

Matrix Spike (MS) - A sample prepared by adding a known'amount of target analyte to a specified amount of matrix sample for which an independent estimate of the target analyte concentration is available. Used to determine the effect of matrix on a method's recovery efficiency.

Matrix Spike Duplicate (MSD) - A known amount of target analyte added to two samples taken from and representative of the same population and carried through all steps of the analytical procedures in an identical manner. Used to assess variance of the sample analysis.

59

Maximum Contaminant Level (MCL) - The average concentration level for a single analyte that will result in a 4-mrem per year total effective dose equivalent (TEDE) based on target organ dose methodology.

Method Detection Limit (MDL) - The concentration of a substance that can be measured and reported at the 99% confidence level to be greater than zero.

Minimum Detectable Activity (MDA) - Analogous to the LLD but includes conversion factors to relate background count rate to analyte activity.

Minimum Detectable Concentration (MDC) - A level analogous to the LLD but includes conversion factors to relate background count rate to analyte concentration.

Relative Percent Difference (RPD) - A measure of the precision of two results, defined as the absolute difference divided by the average of the two results multiplied by 100.

Required Detection Limit (RDL) - Analysis sensitivity requirements required by contract or SOW. Compliance is determined by comparison with sample specific MDCs or MDLs.

Total Propagated Uncertainty (TPU) - Includes all factors.that contribute to the overall uncertainty including counting statistics, sample mass, chemical yield and calibration factors.

60

10 Acronyms Co-60 Cobalt -60 CRDL Contract required Detection Limit CSM Conceptual Site Model Cs-137 Cesium 137 CYAPCo Connecticut Yankee Atomic Power Company DOE Department of Energy EOF Emergency Operations Facility EPA Environmental Protection Agency FDR Field Daily Reports GMP Groundwater Monitoring Program GPC Gas Proportional Counting GWMP Groundwater Monitoring Program HNP Haddam Neck Plant HTD Hard to Detect LCS Laboratory Control Sample LSC Liquid Scintillation Counting LP License Termination Plan MAPEP Mixed Analyte Performance Evaluation Program MCL Maximum Contaminant Level MDC Minimum Detection Concentration MDL Minimum Detection Limit MS Matrix Spike MSL Mean Sea Level NCR Nonconformance Reporting NELAC The National Environmental Laboratory Accreditation Conference NSWPT National Standards for Water Proficiency Testing Studies Criteria 61

NRC Nuclear Regulatory Commission NTU Nephelometric Turbidity Unit PAB Primary Auxiliary Building pCi/L picocurie per liter QAP Quality Assurance Program QAPP Quality Assurance Project Plan QA/QC Quality Assurance/Quality Control RCB Reactor Containment Building RESL Radiological and Environmental Sciences Laboratory RPD Relative Percent Difference SOC Substance of Concern SOP Standard Operation Procedure Sr-90 Strontium-90 TEDE Total Effective Dose Equivalent TPU Total Propagated Uncertainty WP&IR Work Plan and Inspection Record 62

TABLES

Table 2-1: Summary of Monitoring Wcll Information Depth2 Depth2 to Hydro-toTop of Bottom of stratigraphic Well ID Northing Easting Elevation' Screen (ft)

Screen (ft) Unit Well Status AST-1 236310.83 668931.59 21.55 10 20 Unconsolidated 0 9/1 7/2 0 0 4A AST-2 236322.94 668948.16 19.99 5

15 Unconsolidated

• 0 9/ 17/2 00 4A AST-3 236327.17 668909.46 21.2 5

15 Unconsolidated 0 9/ 17/2 0 04 A AST-4 236341.10 668927.83 20.73 5

15 Unconsolidated 09/ 17/ 20 04 A EOF Supply-1 NSD NSD NSD 780 800 Deep Bedrock Active EOF Supply-2 NSD NSD NSD 1130 1150 Deep Bedrock Active MW-EOF-I 237503.96 667408.75 24.08 6

16 Unconsolidated Active MW-EOF-2 237513.48 667418.44 24.12 7

17 Unconsolidated Active MW-i 235304.54 670604.26 12.21 28 38 Unconsolidated Active MW-2 235677.79 670527.35 15.99 29 39 Unconsolidated Active MW-3 235488.22 670555.25 10.75 12 22 Unconsolidated Active MW-4 235638.02 670371.60 15.03 26.5 36.5 Unconsolidated Active MW-5 NSD NSD NSD 73 93 Unconsolidated 0 7/07 /2 00 4A MW-6 NSD NSD NSD 58 108 Unconsolidated 0 7/0 7/2 0 0 4A MW-7 NSD NSD NSD 38 58 Unconsolidated 0 7/07 /20 04A MW-8 NSD NSD NSD 58 88 Unconsolidated 0 7/0 7/2 0 0 4A MW-9 NSD NSD NSD 66 116 Unconsolidated 0 7/0 6/2 0 0 4A MW-10 NSD NSD NSD 48 98 Unconsolidated 0 7/0 7/2 004 A MW-11 NSD NSD NSD 56 66 Unconsolidated 0 7/0 7/2 004 A MW-12 NSD NSD NSD 57 97 Unconsolidated 0 7/0 6/2 004A MW-13 235130.81 670766.81 20.04 66 96 Unconsolidated Active MW-14 NSD NSD NSD 66 86 Unconsolidated 0 7/08 /20 04 A MW-15 NSD NSD NSD 31 81 Unconsolidated 0 7/07/ 20 04 A MW-16D NSD NSD NSD 43 113 Unconsolidated 0 7/07/ 20 04 A MW-16S NSD NSD NSD 4.5 24.5 Unconsolidated 0 7/07/ 20 04 A MW-17 NSD NSD NSD 37 107 Unconsolidated 0 7/07/ 20 04 A MW-18 NSD NSD NSD 30 60 Unconsolidated 0 7/0 6/2 0 0 4A MW-100D 236964.21 668415.29 16.45 21 31 Deep Bedrock Active MW-100S 236959.88 668418.62 16A5 3.50 9

Unconsolidated Active MW-lO1D 236845.02 668655.36 20.82 39.80 49.8 Deep Bedrock Active MW-1OIS 236842.33 668653.70 20.62 8.00 18 Shallow Bedrock Active MW-102D 236651.79 668905.29 20.66 43.00 53 Deep Bedrock Active MW-102S 236655.03 668907.67 20.53 12.80 22.5 Shallow Bedrock Active MW-103D 236672.34 668730.02 21.05 45.00 55 Deep Bedrock Active MW-103S 236671.52 668726.05 20.94 15.50 24.5 Shallow Bedrock Active MW-104S 236673.17 668493.30 20.1 13.00 23 Unconsolidated Active MW-105D 236534.06 668645.74 20.66 45.50 55.5 Deep Bedrock 0 8/12/ 20 04A MW-IOSS 236536.03 668642.86 20.66 14.50 24.5 Unconsolidated 0 8/12/ 20 04D MW-106D 236464.64 668730.32 20.7 45.00 55 Deep Bedrock Active MW-106S 236473.85 668738.10 20.56 14.50 24.5 Shallow Bedrock Active MW-107D 236374.52 668874.54 20.52 90.00 100 Shallow Bedrock Active MW-107S 236371.27 668871.82 20.39 15.00 25 Unconsolidated Active NOTES 1:

Elevations from Kratzert, Jones and Associates, Bold values are based on Malcolm Pirnie data.

2:

Screen depths based on construction logs.

NSD: No survey data available A Well abandoned on this date D: Well was converted to DW-105 on this date.

63

Table 2-1: Summary of Monitoring Well Information (continued)

Depth2 Depth to Hydro-toTop of Bottom of stratigraphic Well ID Northing Easting Elevation' Screen (f)

Screen (ft)

Unit Well Status MW-108 236243.62 669142.69 12.15 15 25 Unconsolidated Active MW-109D 236327.48 668450.18 20.54 45.00 55 Shallow Bedrock Active MW-109S 236329.11 668448.13 20.64 15.00 25 Unconsolidated Active MW-11OD 236083.96 668812.01 22.83 70.00 80 Shallow Bedrock Active MW-lbIS 236081.77 668815.38 22.47 15.00 25 Unconsolidated Active MW-IllS 235931.47 668940.43 18.21 15 25 Unconsolidated 0 9/1 7/2 0 04 A MW-112S 235797.44 669204.17 14.51 15 25 Unconsolidated Active MW-113S 235773.51 669398.06 13.56 15 25 Unconsolidated Active MW-1 14S 236615.50 668820.92 20.76 7.5 17.5 Unconsolidated Active MW-115S 236603.10 668837.00 20.81 7

17 Unconsolidated Active MW-117S 235070.57 671286.68 15.95 15 25 Unconsolidated Active MW-122D 236490.49 668988.55 19.99 184.70 194.7 Deep Bedrock Active MW-122S 236486.50 668988.86 19.84 9

19 Unconsolidated Active MW-123 236629.95 668473.66 20.19 23.5 33.47 Shallow Bedrock Active MW-124 236478.85 668448.53 20.81 11 21 Unconsolidated Active MWV-125 236324.23 668797.83 20.31 11 22 Unconsolidated Active MW-200 236230.82 673217.72 54.68 8

18 Unconsolidated Active MW-201 235811.20 673214.61 58.74

.25 35 Unconsolidated Active MW-202 236176.51 672987.49 51.64 10 20 Unconsolidated Active MW-203 236099.24 672994.67 46.21 8

18 Unconsolidated Active MW-204 235928.48 673033.93 41.88 5

15 Unconsolidated Active MW-205.

235826.44 673093.28 40.57 5

15 Unconsolidated Active MW-206 235789.83 673016.63 43.10 5

15 Unconsolidated Active MW-207 236021.60 673148.93 46.99 15 25 Unconsolidated Active MW-208 235742.54 673120.08 50.21 12 32 Unconsolidated Active MW-502 236770.63 668013.02 17.90 20.54 30.22 Unconsolidated Active MW-503 236928.27 667916.80 15.31 25.14 34.83 Unconsolidated Active MW-504 236881.63 668116.16 16.66 18.97 28.67 Unconsolidated Active MW-505 237062.99 668090.60 14.98 16.37 25.07 Deep Bedrock Active MW-507D 236799.08 668299.65 18.56 67 77 Deep Bedrock Active MW-507S 236795.86 668303.57 18.46 10.88 20.88 Deep Bedrock Active IvW-508D 236663.18 668190.54 17.78 81.5 91.5 Shallow Bedrock Active MW-508S 236666.79 668193.26 17.63 14 24 Unconsolidated Active TPW-1 NSD NSD 9.5 80 100 Unconsolidated.

Active TPW-2 NSD NSD 9.5 80 110 Unconsolidated Active TW-1 235020.46 670967.37 17.73 94 112 Unconsolidated Active TW-2 235292.04 670515.44 9.67 101 104 Unconsolidated Active TW-3 235285.23 670802.16 13.02 49 89 Unconsolidated Active TW-4 235087.35 671193.58 10.71 80 120 Unconsolidated Active Well-A NSD NSD NSD 37 47 Unconsolidated Active Well-B NSD NSD NSD 45 57 Unconsolidated Active 10-2 NSD NSD 10.2 58 63 Unconsolidated Active 8-2 NSD NSD NSD 40 47 Unconsolidated Active 9-2 NSD NSDNSD 50 57 Unconsolidated Active NOTES 1:

Elevations from Kratzert, Jones and Associates, Bold values are based on Malcolm Pirnie data 2:

Screen depths based on construction logs.

NSD: No survey data available A Well abandoned on this date 64

Table 2-2: Selected Events in Operation of the Water Level Monitoring System at HNP Event Date Comment I

Transducer system installed January 2004 Recording water level at 1-minute intervals 2

Batteries fail in river 22 February 2004 Cold weather caused early battery transducer failure. Missing data were approximated using TW-1 as a surrogate.

3 Reconfigured wellheads to May 2004 Suspension systems were added to improve transducer allow removal of well caps without suspension system disturbing the transducers.

Reprogrammed to record on 5-minute intervals.

-65

Table 2-3: Summary of Groundwater Elevation Conditions Observed in the Unconsolidated Hydrostratigraphic Unit During the First Quarter 2004 General Water Responsive to Exhibits Tidal Responsive to Elevation Conditions Local Response?

Dewatering Precipitation?

Activities?

Variable but generally MW-100S stable at approx +14 fR Yes No No MSL MW-1045 Variable around Approx Yes No No MW-104S

+10 ft MSLYeNoo MW-lOSS Declining from +8.5 ftYes No Yes MW-105S MSL to +5 ft MSLYeNoYs MW-107S Declining from +7.5 ftYes Yes Yes MW-107S MSL to +5 ft MSL Yes Yes No MW-10S Approx +5 ft MSL Yes Yes No MW-109S Approx +3 ft MSL Possible Yes No MW-11iS Approx +2 ft MSL Yes Yes No MW-113S Approx +2 ft MSL Yes Yes No MW-I1145 Declining from +8 ft Yes No Yes MSL to +6 ft MSL MW-122S Declining from +9.5 ft Yes Yes No MW-122S MSL to +6.5 ft MSL YsYsN MW-124 Approx. +3.5 ft MSL No No No MW-504S Approx +4 ft MSL No No No MW-508S Approx +11.5 ft MSL Yes No No TW-1 Approx +2 ft MSL Yes Yes No NOTES MSL:

Mean sea level elevation 66

Table 2-4: Summary of Groundwater Elevation Conditions Observed in the Shallow Bedrock Hydrostratigraphic Unit During the First Quarter 2004 GnrlWtr Responsive to Exhibits Tidal Responsive to Well ID l Elevation Conditions Local Response?

Dewatering Precipitation?

RsoeActivities?

MW-1OIS Small variations around Yes No No

+16 ft MSL MW-102S Variable around +11 ft Yes No No MSL MW-103S Variable with general Yes No Not apparent decline from +10 ft MSL to +7 ft MSL MW- 06S General decline from Yes No Yes - slight

+7 ft MSL to +4 ft MSL

-response to mat sump MW-107D General decline from Yes - slight Yes Not apparent

+7 ft MSL to +5 ft MSL MW-109D Generally stable at Responds to river Yes No about +6 ft MSL changes MW-IIOD Small variations around Responds to river Yes No

+4 ft MSL changes MW-508D Small variations around Responds to river Yes No

+4 ft MSL changes NOTES MSL:

Mean sea level elevation 67

Table 2-5: Summary of Groundwater Elevation Conditions Observed in the Deep Bedrock Hydrostratigraphic Unit During the First Quarter 2004

. Vell ID General Water Responsive to Exhibits Tidal Denivatering elIDLocal eacteivites Elevation Conditions Prcptto?

Response?

MW-1i0D Variable with general Yes No Slight response to decline from +10 ft mat sump MSL to +5 ft MSL MW-102D General decline from Yes No Very slight

+10 ft MSL to +6 ft response to mat MSL sump MW-103D General decline from Slight No Very slight

+10 ft MSL to +6 ft response to mat MSL sump MW-105D General decline from Yes Very slight Not apparent

+10 ft MSL to +6 ft MSL MW-106D General decline from Slight Very slight Very slight

+8 ft MSL to +5 feet response to mat MSL sump MW-122D Slight decline from +5 Responds to river Yes No I

ft MSL to +4 ft MSL changes NOTES MSL:

Mean sea level elevation 68

Table 2-6: Summary of Static Water Levels in Monitoring Wells for March and June 2004 Used to Complete Groundwater FloW Maps 1st. Quarter 2nd. Quarter 2/12104 at 2/12104 at 6/12/04 at 6/12104 4:35 11:35 21:00

@15:10 High Tide Low Tide High Tide Low Tide Material Well TOC Groundwater Groundwater TOC Groundwater Groundwater Screened In Well Name Elevation Elevationz')

Elevation" t

Elevation)

Elevation")

Elevationl)

(U. SB, DB)

MW-101D 20.86 9A6 9.41 20.82 8.92 9.00 DB MW-102D 20.65 8.33 8.30 20.66 6.02 6.11 DB MW-103D 21.06 8.05 8.00 21.05 5.19 5.23 DB MW-105D 20.68 9.15 9.05 20.66 5.25 5.28 DB MW-106D 20.69 7.14 7.03 20.70 4.86 4.80 DB Mat Sump 21.72

-20.37

-17.67 21.72

-18.21

-21.67 DB MW-122D 20.00 4.78 4.33 19.99 3.81 3.60 l

DB MW-101S 20.66 16.22 16.18 20.62 14.67 14.69 SB MW-1025 20.57 11.54 11.50 20.53 8.34 8A3 SB MW-103S 20.94 9.48 9.43 20.94 5.11 5.13 SB MW-1 06S 20.57 5.88 5.84 20.56 8.36 8.42 SB MW-1 07D 20.54 6.36 6.13 20.52 4.86 4.60 SB MW-109D 20.56 6.44 6.29 20.54 6.14 6.04 SB MW-110D 22.86 3.18 2.86 22.83 2.94 2A6 SB Mat Sump 21.72

-20.37

-17.67 21.72

-18.21

-21.67 SB MW-508D 17.79 4.59 4.25 17.78 2.48 2.23 SB MW-100S 16.47 14.79 14.78 16.45

.13.23 13.34 U

MW-104S 20.11 11.28 11.26 20.10 8.96 9.04 U

MW-105S 20.69 7.30 7.26 20.66 5.13 5.17 U

MW-1 07S 20.44 6.11 6.06 20.39 5.22 5.21 U

MW-108 12.30 5.80 4.89 12.15 4.99 3.82 U

MW-109S 20.65 2.97 2.88 20.64 2.62 2.53 U

MW-110S 22A8 1.44 1.40 22.47 1.39 1.35 U

MW-113S 13.60 1.33 1.26 13.56 0.43 0.33 U

MW-114S 20.78 8.43 8.38 20.76 5.37 5.41 U

MW-1 22S 19.84 8.26 8.25 19.84 6.87 6.95 U

MW-124 20.82 3.41 3.39 20.81 2.93 2.95 U

MW-504S 16.67 3.99 3.98 16.66 3.80 3.81 U

MW-508S 17.81 11.52 11.49 17.63 9.45 9.46 U

Mat Sump 21.72

-20.37

-17.67 21.72

-18.21

-21.67 U

RIVER 7.90 0.66

-1.28 7.90 2.47

-0.40 U

TW-1 17.73 2.05 0.19 17.73 3.00 0.31 U

NOTES U:

Unconsolidated deposits SB:

Shallow bedrock DB:

Deep bedrock 69

Table 2-7: Summary of Groundwater Elevation Conditions Observed in the Unconsolidated Hydrostratigraphic Unit During the Second Quarter 2004 Responsi ve to Exhibits Responsive to Well ID General Water Elevation Conditions Local Tidal Dewatering Precipitat Response?

Activities?

Ion?

MW-OOS Declined from +15 fI MSL to +12 f MSL Yes No No MW-104S Varied with general decline between +16 ft Yes No Possibly MSL to +7 feet MSL MW-105S Varied with general decline between+10 ft Yes No Yes MSL to +4 ft MSL MW-107S Varied with general decline from +8.5 ft Yes Yes Yes MSL to +3.5 ft MSL MWV-108 Varied with general decline from +9 f MSL Yes Yes No to +4 ft MSL MW-109S Varied with general decline from +6 ft MSL Yes Yes No to +2 fI MSL MW-I OS Varied with general decline from +7 ft MSL Yes Yes No to +1 ft MSL MW-113S Varied with general decline from +7 ft MSL Yes Yes No to 0 ft MSL MW-114S Varied with general decline from +13 ft Yes No Yes MSL to +5 ft MSL MW-122S Varied with general decline from +11 ft Yes Yes No MSL to +5 ft MSL MW-124 Varied with general decline from +6 ft MSL No Yes No to +3 f MSL MW-504S Varied with general decline from +7 ft MSL Yes Possible No to +3 ft MSL MWV-508S Varied with general decline from +12 fI Yes No No MSL to +9 fI MSL TW-i Varied with general decline from +7 f MSL Yes Yes No to 0 MSL NOTES MSL:

Mean sea level elevation 70

Table 2-8: Summary of Groundwater Elevation Conditions Observed in the Shallow Bedrock Hlydrostratigraphic Unit During the Second Quarter 2004 General Water Responsive to Exlibits Tidal Responsive to WVell ID Elvto odtosLocal RsoeDewatering Elevation Conditions Precipitation?

Response?

Activities?

MWV-1OIS Variable with general Yes No No decline from +18 ft MSL to +14 MSL MW-102S Variable with general Yes No Yes decline from +15 ft MSL to +6 ft MSL MW-103S Variable with general Yes No Yes decline from +13 ft MSL to +3 ft MSL MW-106S Variable with increase Yes No Yes from +4 fi MSL to +11 ft MSL between March and May and subsequent decline from

+11 ftMSLto+7fl MSL MW-107D Variable with general Yes - also Yes Yes decline from +10 ft responds to river MSL to +3 ft MSL change MW-109D Variable with general Responds to river Yes No decline from +8 ft MSL change to +6 ft MSL MW-1 lOD Variable with general Responds to river Yes No decline from +7 ft MSL change to +2 ft MSL MW-508D Variable with general Responds to river Yes No decline from +7 ft MSL change to +3 ft ML NOTES MSL:

Mean sea level elevation 71

Table 2-9: Summary of Grounidwater Elevation Conditions Observed in the Deep Bedrock Hydrostratigraphic Unit During the Second Quarter 2004 General Water Elevation Responsive to Exhibits Tidal Responsive to Vell ID Conditions Local Dewatering Activities?

Precipitation.?

MW-10ID The transducer at this Yes No Yes. Clearly responds location failed, and the exact to operation of DW-3.

time of failure cannot be determined MWV-102D Variable with general Yes No Yes decline from+12 ftMSL to.

+4 ftMSL MW-103D Variable with general Yes No Yes decline from +12 ft MSL to

+3 ft MSL MWY-105D Variable with general Yes No Yes decline from +12 ft MSL to

+4 ft MSL MW-106D Variable with general Possible Yes Yes decline from +11 fIt MSL to

+3 MSL MW-122D Variable with general Possible Yes Possible. Responds to decline from +7 ft MSL to changes in river stage.

+3 ft MSL NOTES MSL:

Mean sea level elevation 72

Table 3-1: Summary of Field Parameters for March 2004 Field Field Field Field Specific Field Static Water Turbidity DO ORP Field Conductance Temp Level (ft Well ID (NTU)

(mgL)

(mV) pH

(,S/cm)

(°C) below MP)

EOF-2 1.4 5.8 150 7.3 2710 12.2 9.78 MW-100D 0.1 0.5 63 6.4 67 9.4 8.63 MW-100S 0.1 3.3 143 6.7 1630 5.9 6.1 MW-101D 0.9 1.6 185 8.1 0.178 12 13.54 MW-10IS 2

12 275 6.1 0.127 7.2 5.1 MW-102D' 15 6.7';

170' NM8.3 601

-8 NM MW-102S 4

10 231 6.5 0.505 7.2 11.27 MW-103:

-14 13

206 7.6

-'380' NM MW-103S 0.9 13 243 6.4 0.46 11 13.64 MW-104S 9.1 10 255 6.2 264 12 11.31 MW-105S 2

3.5 204 7

0.461 12 15.09 MW-105D 2.1 7.8 196 7.7 0.387 14 14.18 MW-106S 3.5

<0.02 162 6.4 2130 12 15.19 MW-106D 2.5 4.5 140 9.3 335 13 18.88 MW-107D 2.4 3.7 180 6.3 159 13 18.57 MW-107S 2

0.9 280 5.9 412 13 15.87 MW-108S 2.1

<0.01

-42 6.3 115 9

7.17 MW-109D 0.6 1.6 93 7.7 578 12 20.02 MW-109S 3.1 3.4 156 6.4 798 11.9 18.12 MW-11OD 2.9 0.1 17 7.5 282 9.1 20.44 MW-110S 0.4 3

204 6

106 8.8 20.89 MW-111S 2.6 7

256 5.9 170 10.6 17.02 MW-112S 0.8 1

234 5.5 64 10.2 13.21 MW-113S 0.5 0.1 195 5.8 414 11 12.38 MW-114S 3.8 1.4 138 6.9 1440 14 15.15 MW-115S 3.3

-6.1 184 6.5 1200 13 15.2 MW-117S 3.5 0

-100 6.6 707 8.9 11.18 MW-122D 59.5

<0.1

-160 9.4 186 12 17.64 MW-122S 8.9

<0.1

-6 6.5 624 11 14.01 MW-123S 0.1 8.5 148 6.7 856 12.4 14.82 MW-124S 2.3 3.6 240 6.3.

406 11 17.57 MW-125S 4.2 1.5 89 6.7 731 7

16.35 NOTES NM:

NS:

No measurements were taken for this parameter Well was not sampled during this event due to low water level Well was samjled with a bailer 73

Table 3-2: Summary of Field Parameters for June 2004 Field Field Specific Field Static Water Field Turbidity Field DO ORP Field Conductance Temp Level (ft Well ID (NTU)

(mg/L)

(mV) pH (US/cm)

(°C) below MP)

EOF-2 1.6 7.10 103 7.29 577 17.62 12.26 MW 1000 5.11 0.00 22 6.22 103 12.82 9.24 MW 100S 4.4 7.80 220 5.9 88 14.4 6.73 MW 101D

-10 1.67 127 8.1 186 16.5 16.40 MW 101S

-10 8.01 13 7.01 138 17.8 6.40 MW 102D b' 2.9 5.10 100 7.63 '

411 15.4^

14' i4.19 MW 102S 1.8 5.94 184 6.46 155 12.8 15.65 MW 103D 4.1 '

10.50 220 -

5.3.

522 16.5

-21:40 MW 103S

-10 6.97 158 6.71 238 11.3 16.70 MW 104S 1.6 13.74 178 6.69 583 17.51 17.60 MW 105D 3.8 7.90 110 7.7 517 15.1 17.24 MW 105S 1.9 1.60 160 6.9 540 14.6 16.61 MW 106D 2.7 4.89 62 9.38 363 18 18.62 MW 106S 2.3 1.76 155 6.29 1770 15.4 16.52 MW 107D 3

2.66 99 6.28 108 19.38 19.80 MW 107S 3.7 3.47 199 5.76 737 18.37 16.77 MW 108S 4.7 1.00

-72 6.48 109 13.41 9.30 MW 109D 8

2.31 134 7.37 414 16.91 18.99 MW 109S 3

8.87 285 5.13 2

22.84 18.49 MW 1100 7

0.70 40 7.4 311 18.5 21.20 MW 110S 1.9 5.30 200 6.1 508 17.3 21.26 MW IllS 2.4 7.80 180 6.3 151 14.6 17.29 MW 112S 2.4 1.10 290 5.1 104 13.1 13.70 MW 113S' 2.5 0.40 250 5.8 298 15.2 12.65 MW 114S

-10 1.39 85 6.96 318 16.2 16.97 MW 115 NS MW 117S 21 6.50

-100 6.5 637 13.4 12.81 MW 122D 27 1.00

-150 9.3 183 17.6 18.61 MW 122S 4.7 11.00

-2 6.79 763 18.09 14.81 MW 123 1.1 12.70 186 6.61 747 15.47 15.55 MW 124 0.6 10.26 153 6.66 368.

17.64 17.91 MW 125 2.2 1.42 22 6.85 578 18.4

'16.62 MW-1 6.9

.0.80

-110 6.6 1900 7.6 0.93 MW-2 3

0.04 98 6.32 253 17.64 14.57 MW-3 180 0.04

-80 6.5 130 12 11.36 MW 502 3.83 0.00

-159 7.02 450 14.66 14.57 MW 503 2.22 0.94

-106 6.21 467

'14.22 11.95 MW 504S 3

0.35

-90 6.6 321 20.4 13.85 MW 505 3.1 0.00

-139 7.26 556 12.03 4.09 MW 507D 3.68 0.40

-83 7.5 179 22.19 16.22 NOTES NM:

No measurements were taken for this parameter NS:

Well was not sampled during this event due to low water level Well was samnjpid with a bailer 74

Table 3-2: Summary of Field Parameters for June 2004 (continued)

Field Field Specific Field Static Water Field Turbidity Field DO ORP Field Conductance Temp Level (ft Well ID (NTU)

(mg/L)

(mV) pH (pS/cm)

(C) below MP)

MW 507S 5.29 0.00

-110 6.67 430 16.78 8.20 MW 508D 2.6 7

120.00 7.5 174 16.4 15.85 MW 508S 3.1 5.70

-60 6.6 398 20.2 7.92 NOTES NM:

NS:

No measurements were taken for this parameter Well was not sampled during this event due to low water level Well w'as saimled iwith a bailer 75.

(

c (

Table 4-1: Boron Concentrations (pGJL) in Groundwvater

(

Well ID Mar-99 Apr-99 Sep-99 Jun-00 Jun-01 Dec-01 Mar-02 Jun-02 Sep-02 Dec-02 Mar-03 Jun-03 l Sep-03 Dec-03 Mar-04 Jun-04 100D

<50 30.8 ND 10.8

<200

<50 68

<250

<50

<50

<27

<10

<27 6.3 19.9 10.4 100S

<50 22.8 ND NS

<200

<50 710

<250 188 84.9 123 1,145 428 140 212 25.3

. 101D 61.3 57.7 ND 38.1 25.4

<50

<50

<250 NS

<50 83.5 47 42.3 30 49.4 54 101S 29.7 28.2 ND 53.8 34.4 77

<50

<250 NS

<50 NS 43 235 47 49 68.6 102D 270.4 114.7 ND 87.5

80. 1 290 96.4

<250 NS 428 64.2 392 110 98 113 97.1

• 102S 43.9 29.7 ND 63.4 80.8 220 64.3

<250 NS

<50 49 19 117 49 60.8 91.2 103D 253.3 165.2 ND 63.6 57.9 88 165

<250 NS 69.5 105 76 58 48 90.9 57.1 103S 214.9 364.5 ND 150.0 111 260 55.4

<250 NS 118 96.2 92 184 33 85.7 165 104S

.<50 47 ND NS 54.2 82 74 70.2 81.8 75.6 76.4 110 143 200 299 274 105D 144.2 65.2 ND

51. 7 34.7 64

<50

<250 NS 58.5 60.4 41 67.1 59 67.5 60.8 105S 7,470 9,590 ND 2,940 1,760 2,400 1,340

<250 NS 945 915 618 1,200 540 735 484 106D 76.8 69.2 ND.

52.2 40.4

<50

<50

<250 NS 69.4 51.3 51 51.7 59 74.3 64.7 106S 2,074 1,307 ND NS 960 720 468

<250 NS 222 348 239 786 530 670 490 107D 41.2 95.4 ND

• 30.9 18.4

<50

<50

<250

<50

<50

<7 173

<30 21 38 32.1 107S 100 108.7 ND 91.0 169 180 160

<250

<50 102 105 66 278 120 192 177

• 108S

<50 62.8 ND NS 82.9 120 100

<250 NS NS NS NS NS NS NS 68.3 109D 523 577 ND 401.0 157 200 150

<250 NS 59.4 183 26 NS NS 210 191 109S 70 88.7 ND 107.0 112 170 54

<250 510 179 76.8 126 203 190 254 124 1 1OD 337.7 316.5 ND 234.0 289 320 250

<50 265 203 93.3 127 334 170 179 236 110S 172.6 547 ND 131.0 90.7 81 100

<250 97.3 179 320 162 206 180 238 291 111S

<50 61.8 ND 60.9 45.8

<50 52

<250 NS' 61.5 37.2 52 58.1 NS NS 55.5 112S

<50 65.1 ND NS 23.9 61

<50

<50 NS NS NS NS NS NS NS 47.8 113S 120 141.7 ND NS 136 180 100 89.8 NS NS NS NS NS NS NS 110 114S 422 290.2 ND 265.0 240 NS 134 201 NS 127 NS 90 203 140 173 1260 115S 76.3 145.6 ND 94.2 80.7 NS 175 149 NS 178 90.4 78 NS 100 195 NS 117S 50 62.2 ND NS 17.8 57 75 59.7 NS NS NS NS NS NS NS 68.5 122D NI NI NI NI NI NI NI NT NT NI 178 179 178 180 224 223 NOTES NI:

Well was not installed during sample event.

NS:

Well was not sampled during sample event.

ND:

Well was sampled but data is not available.

<50:

Observed boron concentration was less than the Method Detection Limit (MDL) 76

(7 '

Table 4-1: Boron Concentrations (uG/liter) in Groundwater (continued)

(.

Well ID Mar-99 Apr-99 Sep-99 Jun-00 Jun-01 Dec-01 Mar-02 Jun-02 Sep-02 Dec-02 Mar-03 Jun-03 Sep-03 Dec-03 Mar-04 Jun-04 122S NI NI NI NI NI NI NI NI NI NI 237 219 178 330 317 307 123S NI NI NI NI NI NI NI NI NI NI 64.6 46 67.8 88 107 90.8 124S NI NI NI NI NI NI NI NI NI NI 351 299 312 300 228 225 125S NI NI NI NI NI NI NI NI NI NI 426 365 489 360 390 445 AST-1

<50 36 ND 36.0 17.1

<50

<50 NS NS NS NS NS NS NS NS NS MAT NS NS ND 177.0 NS NS NS 128 NS NS NS

• NS NS NS NS NS EOF 2

<50 46.2 ND NS 46.2 65 70 72.3 NS NS NS NS NS NS NS 63.4 TW-1

<50 12.7 ND NS

<200

<50

<50 NS NS NS NS NS NS NS NS NS MW-13

<50 14.7 ND NS 13.1

<50

<50 NS NS NS NS NS NS NS NS NS MW1 NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS 5.08 MW2 NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS 15.5 MW3 NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS 5.67 MW502 NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS 65.2 MW503 NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS 10.7 MW504 NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS 42.7 MW505 NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS 54.4 MW507D NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS 36.7 MW507S NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS 52.8 MW508D NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS 66.1 MW508S NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS 41.9 NOTES NI:

Well was not installed during sample event.

NS:

Well was not sampled during sample event.

ND:

Well was sampled but data is not available.

<50:

Observed boron concentration was less than the Method Detection Limit (MDL) 77

Table 4-2: Gross ca fi, Sr-90 and Cs-137 Concentrations (OCi/L) in Groundwater Well ID Sample Gross a Gross.6 Sr-90 Cs-137 2002Q1 c<5.01 2002 Q2

<2.89 2002 Q3

<0.83 3.59

<3.22 2002 Q4

<0.875 2.37

<3.46 2003 Q1

<0.672 3.02

<4.09 MW-100D 2003 Q2 2.00 6.60

<5.9 2003 Q3

<0.916

<2.68

<4.22 2003 Q4 0.78 2.58

<7.76 2004 Q1

<0.952 1.31

<3.59 2004Q2 2.38

<2.29

<4.32 2002Q1 3.21 2002Q2

<2.18 2002 Q3 0.60 5.72

<3.59 2002Q4

<4.02 19.30

<3.18 2003 Q1

<1.24 8.73

<4.65 MW-100S 2003Q2

<1.8 4.76

<6.5 2003Q3

<0.914 4.00

<4.18 2003 Q4

<1.41 6.52

<7.48 2004Q1

<2.8 4.23

<3.13 2004 Q2

<2.27 1.51

<2.21 2002Q1

<2.92 2002Q2

<3.12 2002 Q3 5.84 6.18

<0.583

<3.52 2002 Q4 4.80 5.84

<3.11 2003 Q1 5.34 6.65

<6.21 MW-l01 2003 Q2 5.09 9.12

<8.7 2003 Q3 6.41 5.81.

<3.82 2003 Q4 6.02 4.95

<8.19 2004Q1 6.52 1.70

<1.16

<7.09 2004 Q2 8.50 6.18

<1.23

<3.52 MW-101S 2002Q1

<2.78 2002Q2 1.64 2002Q3 0.91 5.74 0.55

<3.15 2002 Q4

<0.643 2.45

<3.09 2003 Q1

<0.769 2.82 0.38

<4.06 2003Q2

<2.1 3.32

<1.7

<8.3 2003 Q3 0.85 4.86 0.33

<4.78 NOTES Well was not sampled for analyte

<50:

Observed concentration was less than the MDC Bold Sr-90 concentrations are greater than EPA MCL 78

Table 4-2: Gross a, P, Sr-90 and Cs-137 Concentrations (pCi/liter) in Groundwater (continued)

Well ID Sample Gross a Gross.8 Sr-90 Cs-137 Event 2003 Q4 0.79 7.55 0.47

<9.3 2004Q1

<0.977 1.87

<1.2

<4.31 2004 Q2 1.59 3.27

<1.2

<3.59 2002 Q1 9.74 7.42

<0.664

<2.41 2002Q2 5.53 6.97

<0.721 1.98 2002 Q3 8.93 8.69

<0.636 6.14 2002 Q4 5.55 50.10

<0.85 6.69 MW-102D 2003 Q1 3.57 15.60

<0.578 12.70 2003 Q2 8.60 58.10

<1.6

<6.1 2003 Q3 2003Q4 11.10 11.10

<1.25

<8.71 2004Q1 11.30 6.89

<1.11

<3.92 2004 Q2 8.51 9.95 0.93

<3.43 2002Q1 1.05 6.15

<0.716

<3.05 2002 Q2 1.48 4.52

<0.716

<3.01 2002Q3 1.01 5.16

<0.52

<2.98 2002 Q4 0.76 3.05

<0.644

<3.4 MW-102S 2003 Q1

<0.84 4.68 0.38

<4.85 2003 Q2 1.52 4.70 1.08

<10 2003 Q3 0.94 5.73 0.55

<4.61 2003 Q4

<1.28 4.95

<1.26

<7.25 2004Q1

<1.5 2.28

<1.2

<3.67 2004Q2 1.66 2.05

<1.2

<5.06 2002 Q1 3.07 3.38

<0.603

<2.78 2002 Q2 6.87 7.39

<0.691

<2.19 2002 Q3 8.63 12.90

<0.63

<3.64 2002 Q4 4.64 5.42

<0.593

<3.3 MW-103D 2003 Q1 4.11 5.68

<1.78

<3.58 2003 Q2

<2.6 4.85

<1.9

<7.3 2003Q3 2003 Q4 4.40 6.70 0.37

<7.7 2004 Q1 5.19 6.06

<0.815

<2.7 2004 Q2 2.72 3.36 1.26

<2.23 MW-103S 2002 Q1 1.85 37.6 5.23 30.2 2002Q2 1.64 81.5 15.30 58.5 2002 Q3 1.57 46.0 3.81 38.1 2002 Q4 0.68 40.6 5.57 38.0 2003 Q1 4.33 76.9 6.75 87.6 2003Q2

<0 42.2 1.13 26.6 NOTES Well was not sampled for analyte c50:

Observed concentration was less than the MDC Bold Sr-90 concentrations are greater than EPA MCL 79

Table 4-2: Gross a, fi, Sr-90 and Cs-137 Concentrations (pCi/liter) in Groundwater (continued)

Well ID SEvent Gross a Gross l

Sr-90 Cs-137 2003 Q3 1.25 41.8 2.59 38.1 2003 Q4 1.05 13.50

<0.615 13.50 2004 Q1 1.53 27.80 2.27 22.40 2004 Q2 2.33 23.50 1.34 7.50 2002Q1

<5.23 2002 Q2

<2.2 2002 Q3 2.85 14.80

<3.35 2002 Q4 1.01 6.90

<3.09 MW-104S 2003 Q1 0.73 7.56

<5.23 2003 Q2 6.10 42.87 3.14

<8.5 2003 Q3 3.86 18.00 2.02

<4.29 2003 Q4 1.52 9.06 0.86

<8.76 2004 Q1 1.25 4.11

<0.685

<2.09 2004 Q2 2.49 6.23

<1.35

<2.26 2002 Q1 1.47 4.72

<0.571

<2.67 2002 Q2 1.39 2.33

<0.597

<2.26 2002 Q3 3.06 6.69

<0.738

<3.17 2002Q4 2.15 5.72

<0.596

<3.12 MW-105D 2003 Q1 2.43 4.46 0.66

<4.17 2003 Q2 3.59 9.01

<1.5

<7.9 2003 Q3 6.70 6.62

<0.427

<3.47 2003 Q4 5.08 5.78 1.33

<10.10 2004 Q1 2.59 3.56

<0.811

<2.48 2004 Q2 5.30 5.67 1.11

<2.33 2002Q1 1.11 242.

122.

<2.48 2002Q2

<1.34 238.

116.

<2.55 2002Q3

<1.17 180.

101.

<3.29 2002 Q4

<0.872 159.

83.3

<3.37 2003Q1

<1.04 253.

138.

<4.23 MW-105S 2003Q2

<3.2 490.1 181.6

<4.7 2003 Q3

<1.69 45.5 (NV) 197.

<3.64 2003Q4 0.79 297.

144

<8.14 2004Q1

<1.2 192.

91.8

<1.86

_2004Q2

<2.01 44.3 16.2

<2.03 MW-106D 2002 Q1 1.03 5.89

<0.597

<3.18 2002Q2 1.13 6.01

<0.527 1.92 2002Q3 1.16 8.31

<0.546

<2.4 2002Q4 1A3 4.27

<0.624

<2.4 2003Q1 1.19 7.40 0.36

<3.97 NOTES OT -.

Well was not sampled for analyte

<50:

Observed concentration was less than the MDC Bold Sr-90 concentrations are greater than EPA MCL 80

Table 4-2: Gross a, f, Sr-90 and Cs-137 Concentrations (pCi/liter) in Groundwater (continued)

Well ID Sample Gross a Gross l Sr-90 Cs-137 Event__

2003Q2 3.02 10.94

<1.5

<10 2003 Q3 2.45 10.30 0.80

<4.25 2003 Q4 4.76 7.73 0.50

<6.9 2004Q1 2.75 4.12

<1.17

<2.24 2004Q2 1.16 3.23

<1.2

<2.11 2002 Q1 1.36 25.40 8.38

<2.05 2002 Q2

<1.24 34.00 13.00

<2.28 2002 Q3

<1.49 11.20 2.26 2.76 2002 Q4

<1.26 23.20 9.35

<2.55 MW-106S 2003Q1 1.01 36.10 13.50

<4.54 2003 Q2

<3.1 54.60 18.68

<8.5 2003 Q3

<5.33 801. (NV) 3.71

<4.77 2003 Q4 2.25 19.70 4.35

<9.28 2004Q1 1.54 13.90 1.21

<1.98 2004 Q2 2.73 19.50 3.17

<2.61 2002Q1 1.98 5.38

<0.628

<3.11 200202 1.30 3.87

<0.6

<2.65 2002 Q3 0.81 5.30

<0.557

<2.64 200204 1.10 3.97

<0.572

<2.75 200301 1.16 4.02

<3.87 MW-107D 200302

<0 4.40

<1.7

<5.4 2003 Q3

<2.56 3.72 0.33

<4.25 2003 Q4 0.92 3.01

<0.669

<9.04 2004 Q1 1.33 5.79

<1.23

<4.4 2004 Q2

<2.53 7.00

<1.2

<3.61 2002Q1

<4.37 2002 Q2

<0.944 4.61 0.26

<2.42 2002Q3

<1.14 5.11

<0.593

<3.43 2002 Q4

<0.822 2.77 0.44

<2.65 2003 Q1 0.63 3.49 0.54

<3.29 MW-107S 2003 Q2

<2.7 4.20

<1.9

<7.6 2003 Q3

<0.923 4.40 0.36

<5.18 2003 Q4

<1.29 1.73 0.54

<9.23 2004Q1

<1.28 1.55

.<1.37

<3.52 2004 Q2

<2.66 1.69 2.69

<3.39 MW-108S 2002Q1

<4.16 2002Q2

<2.25 2002Q3 1.16 9.36

<3.25 2002 Q4 0.55 2.51

<2.31 NOTES Well was not sampled for analyte

<50:

Observed concentration vas less than the MDC Bold Sr-90 concentrations are greater than EPA MCL 81

Table 4-2: Gross a, fB Sr-90 and Cs-137 Concentrations (pCi/liter) in Groundwater (continued)

Well ID Sample Gross a Gross /

Sr-90 Cs-137 2003Q1 0.46 2.16

<4.8 2003 Q2

<2.5 4.00

<4.3 2003 Q3 0.82 2.51

<4.61 2003 Q4 1.45 2.79 0.63

<9.08 2004 Q1

<1.11 2.63

<0.887

<3.6 2004 Q2 3.90 5.72

<1.4

<3.43 2002 Q1 3.70 7.47

<0.666

<2.6 2002 Q2 4.62 5.54

<0.495

<2.52 2002 Q3 3.72 6.20

<0.568

<2.13 2002Q4

<0.834 1.82

<0.646

<3.13 MW-109D 2003Q1 6.52 11.90 2.40 2003Q2 9.00 11.49

<1.9

<8.2 2003 Q3 0.91 5.57

<0.39

<4.34 2003 Q4

<0.497 2004 Q1 6.95 7.60

<1.01

<2.02 2004 Q2 7.78 9.21

<1.16

<8.77 2002 Q1

<1.54 6.33 0.90

<2.88 2002 Q2

<1.23 8.49 0.66

<2.76 2002 Q3

<1.79 12.80 0.97

<3.25 2002 Q4 1.25 10.10 0.90

<3.47 MW-I09S 2003 Q1

<1.5 7.85 0.98

<3.8 2003Q2

<2.9 11.20

<1.7

<6.1 2003Q3

<2.61 11.50 0.69 1.87 2003 Q4

<2.03 10.80 1.01

<9.7 2004 Q1

<1.37 9.63

<1.11

<3.36 2004 Q2

<2.32 6.53 0.80

<2.08 2002 Q1 11.00 12.60

<0.562

<2.84 2002 Q2 7.78 9.14

<0.52

<2.48 2002Q3 7.73 11.20 2.54

<2.17 2002 Q4 8.25 8.83

<0.696

<3.26 MW-IlOD 2003 Q1 6.04 9.95

<0.551

<5.04 2003Q2 6.10 12.00

<1.7

<7.5 2003 Q3 5.82 20.50 0.36

<3.96 2003Q4 8.15 11.50 0.45

<8.19 2004 Q1 7.07 7.14 0.66

< 3.34 2004 Q2 5.63 -

8.50

<1.15

<1.94 MW-110S 2002 Q1

<0.965 4.07 0.34

<3.05 2002 Q2

<0.952 6.51

<0.545

<2.57 2002 Q3

<0.813 4.39

<0.683

<2.72 NOTES NT Well was not sampled for analyte

<50:

Observed concentration was less than the MDC Bold Sr-90 concentrations are greater than EPA MCL 82

Table 4-2: Gross a, P, Sr-90 and Cs-137 Concentrations (pCi/liter) in Groundwater (continued)

Well ID Sample Gross a Grossfi Sr-90 Cs-137 2002 Q4

<0.863 4.28

<0.528

<2.31 2003 Q1

<0.858 7.47 0.32

<4.97 2003Q2

<2.7 7.30

<1.6

<4.6 2003 Q3

<1.93 3.99

<0.423

<3.45 2003 Q4

<1.22 4.70 0.44

<6.15 2004Q1

<1.33 1.88

<1.7

<3.41 2004Q2

<2.44 4.35 0.69

<3.05 2002 Q1 1.00 5.31

<0.629

<2.42 200202

<0.696 2.76

<0.722

<2.8 2002 Q3 0.54 7.39

<3.69 2002 Q4

<0.671 5.01

<0.527

<2.69 MW-111S 2003Q1 0.55 3.24

<3.82 2003Q2

<2.2 5.10

<8.5 2003Q3

<0.714 4.12

<4.5 2003 Q4

<0.657 5.52 0.35

<7.09 2004 Q1 0.73 4.95

<0.788

<3.06 2004Q2

<2.49 2.06

<1.11

<2.4 2002 Q1

<3.35 2002Q2

<1.96 2002 Q3

<0.788 3.61

<3.01 2002Q4

<0.685 1.99

<2.11 2003Q1

<0.717

<2.58

<4.92 2003Q2

<2.1 2.02

.<7.5 2003 Q3

<0.931 2.62

<4.87 2003 Q4

<0.595

<2.5 5.49

<8.17 2004 01

<0.96

<2.38

<0.765

<3.44 2004 Q2 1.56

<1.97 0.70

<4.43 2002Q1

<4.17 2002 Q2

<3.04 2002 Q3 2.95 31.40

<2.94 2002 Q4 1.82 30.30

<3.51 2003 Q1 0.89 23.40

<2.32 MW-11 2003Q2

<3.2 16.80

<1.7

<9.7 2003 Q3

<3.12 23.40 0.58

<0 2003 Q4

<1.53 22.70 0.84

<9.04 2004Q1

<1.93 16.30 0.37

<3.16 2004 Q2

<2.38 8.30 0.67

<2.26 MW-114S 2002Q1 0.68 20.70 3.63

<3.4 2002 Q2 0.95 17.30 3.26

<2.65 NOTES Well was not sampled for analyte

<50:

Observed concentration was less than the MDC Bold Sr-90 concentrations are greater than EPA MCL 83

Table 4-2: Gross a, P, Sr-90 and Cs-137 Concentrations (pCi/liter) in Groundwater (continued)

Well ID Sample Gross a Gross,

Sr-90 Cs-137 Event 2002 Q3

< 0.885 11.50 1.45

< 2.99 2002 Q4

< 0.923 11.60 2.62

< 2.89 2003 Q1

< 3.42 49.10 16.60

< 3.83 2003 Q2 2.98 12.96

< 1.8

< 4.3 2003 Q3

< 1.94 7.24 0.73

< 3.88 2003 Q4

< 1.17 7.70 1.15

< 9.1 2004 Q1

< 1.79 18.50 3.92

< 4.12 2004 Q2 6.29 8.11

< 1.19

< 3.68 2002 Q1 6.38 23.00 3.85 3.18 2002 Q2

< 0.827 5.95 0.52 1.59 2002 Q3 1.30 17.60 2.40 7.59 2002 Q4 1.50 13.20 1.42 3.72 2003 Q1 1.56 11.90 1.33 2.55 2003 Q2

< 2.1 4.60

< 1.5

< 6.6 2003 Q4 1.88 8.49 1.41

< 9.79 2004 Q1 1.42 8.62 1.64 2.84 2002 Q1

< 4.84 2002 Q2

< 2.47 2002 Q3 1.59 8.36

< 3.43 2002 Q4

< 1.27 7.66 1.28

< 3.21 MW-117S 2003 Q1 0.90 8.13 1.41

< 4.38 2003 Q2 3.80 11.66 1.40

< 9.3 2003 Q3

< 2.25 9.49 1.42

< 4.21 2003 Q4

<2.24 9.65 0.77

< 6.78 2004 Q1

< 2.97 5.41

< 1.09

< 3.76 2004 Q2

< 1.44 7.28 0.79

< 4.08 2003 Q1 12.00 12.00

< 0.693

< 4.64 2003 Q2 12.60 27.70 1.21

< 9.2 MW-122D 2003 Q3 21.50 18.70

< 0.398

< 4.02 2003 Q4 9.80 10.80 0.21

< 9.7 2004 Q1 6.20 6.64 0.55 3.19 2004 Q2 7.14 5.21 3.29.

< 3.28 2003 Q1 1.18 6.41 1.59

< 3.56 2003 Q2

< 3.2 14.11

< 1.7

< 8.6 MW-122S 2003 Q3

< 3.49 11.20 1.24

< 2.98 2003 Q4

< 2.19 8.64 0.81

< 9.97 2004 Q1

< 1.58 6.46 0.64

< 3.31 2004 02 4.88 8.40 0.57

< 3.87 MW-123S 2003 Q1 12.90 18.40 0.63

< 4.26 NOTES Well was not sampled for analyte

<50:

Observed concentration was less than the MDC Bold Sr-90 concentrations are greater than EPA MCL 84

Table 4-2: Gross a, f, Sr-90 and Cs-137 Concentrations (pCi/liter) in Groundwater (continued)

Well ID SEvent Gross a Gross a Sr-90 Cs-137 2003 Q2 5.10 24.70

< 1.6

< 5.1 2003 Q4 7.70 14.90 1.37

< 7.97 2004 Q1 4.19 14.70 0.87

<4.31 2004 Q2 4.63 19.60

< 1.34 2.46 2003 Q1

< 1.04 6.24 0.49

< 4.94 2003 Q2

< 2.7 8.30

< 1.6

< 6.7 MW-124S 2003 Q4

< 1.22 5.90 0.54

< 8.73 2004 Q1

< 1.61 5.12

< 1.12

< 3.32 2004 Q2

< 2.2 4.98 1.33

< 3.22 2003 Q1 1.52 10.90 0.69

< 4.4 2003 Q2

< 2.8 14.49 1.41

< 7.4 MW-125S 2003 Q3

< 2.17 16.30 1.17

< 2.5 2003 Q4

< 2.04 15.30 6.51

< 7.44 2004 Q1 1.05 8.89 3.15

< 2.86 2004 Q2.

2.36 11.80 1.78

< 3.88 2002 Q2

< 2.45 2002 Q4 11.40 14.20

< 3.31 MW-200 2003 Q1 2.89 4.86

< 4.88 2003 Q2 20.20 23.40

< 4.9 2003 Q4 0.38 2.77

< 9.36 2002 Q2

< 2.86 2002 Q3 0.51 4.42

< 3.56 2002 Q4 1.39 3.90

< 3.07 MW-201 2003 Q1

< 0.661 3.07

< 4.9 2003 Q2

< 2.6 5.50

< 3.5 2003 Q3

< 1.24

< 2.64

< 3.98 2003 Q4 1.89 2.49

< 9.38 2002 Q1 0.58 1.59

< 0.48

< 2.42 2002 Q2

< 2.77 2002 Q3

< 0.861 3.30

< 3.33 MW-203 2002 Q4

< 0.593 4.04

< 0.758

< 3.21 2003 Q1 2.62 6.60

< 4.11 2003 Q2 6.30 15.60

< 3.3 2003 Q3 0.53 2.33

< 4.78 2003 Q4

< 0.919 3.75

< 5.94 MW-205 2002 Q1

< 3.41 2002 Q2

< 2.64 2002 Q3

< 1.27 3.01 2.51 2002 Q4

< 0.799 2.06

< 3.08 NOTES Well was not sampled for analyte

<50:

Observed concentration was less than the MDC Bold Sr-90 concentrations are greater than EPA MCL 85

Table 4-2: Gross a, jP, Sr-90 and Cs-137 Concentrations (pCilliter) in Groundwater (continued)

Well ID Sample Gross a Gross,l Sr-90 Cs-137 2003 Q1

< 0.679

< 2.54

< 3.5 2003 Q2

< 1.8 2.15

<3.5 2003 Q3

< 1.16 1.31

< 3.58 2003 Q4

< 0.574 1.62

< 8.18 2002 QI 0.60 3.63

< 0.565

< 3.09 2002 Q2

< 2.83 2002 Q3

< 0.635 4.35

< 3.22 MW-207 2002 Q4 0.49 5.40

< 2.64 2003 Q1

< 0.642 3.08

< 3.94 2003 Q2

< 1.9 3.48

< 7.6 2003 Q3

<0.571 1.48 0.44

< 9.35 2003 Q4

< 0.695 2.38

< 9.63 2003 Q2 24.10 42.70

< 7.6 MW-208 2003 Q3

< 0.549 4.14

< 4.72 2003 Q4

< 0.888 3.45 0.89

< 9.88 MW-1 2004 Q2

< 0

< 1.84 0.94

< 2.41 MW-2 2002 Q4

< 0.967 2.75 0.41

< 3.09 MW-2 2004 Q2

< 1.29 4.43

< 1.02

< 3.51 MW-3 2004 Q2

< 1.81 0.79

< 1.24

< 2.47 MW-502 2004 Q2 1.65 5.02

< 2.26 MW-503 2004 Q2 3.23 1.74

< 2.35 MW-504 2004 Q2

< 1.97 3.40

<2.34 MW-505 2004 Q2 1.82 4.88

< 3.12 MW-507D 2004 Q2 28.80 15.20

< 2.39 MW-507S 2004 Q2 1.42 3.95

< 2.25 MW-508D 2004 Q2 7.58 6.68

< 2.76 MW-508S 2004 Q2

< 2.28 4.50

< 3.16 AST-1 2002 Q1

< 5.83 2002 Q1 17.20 13.90

< 0.539

< 2.67 2002 Q2

< 0.463

< 2.59

< 3.27 EOF-2 2003 Q1 0.73 2.84

< 5.32 2003 Q3

< 1.63 3.76

< 5.57 2004 Q2 2.58 3.30

< 3.27 SUPPLY WELL B 2002 Q4

< 0.579 NOTES Well was not sampled for analyte

<50:

Observed concentration was less than the MDC Bold Sr-90 concentrations are greater than EPA MCL 86

(

C;

(

Table 4-3: Tritium Concentrations (pCi/L) in Groundwater Well ID Mar99 Apr99 Sep'99 Jun'00 Jun'01 Dec'01 Mar'02 Jun'02 Sep'02 Dec'02 Mar'03 Jun'03 Sep'03 Dec'03 Dec'030 Mar'04 Jun'04 100D

< 700

< 1000 NS

< MDC

< 270

<210

< 271

< 260 134

< 293

< 259

< 360

< 301 170 189

< 262

< 306 100S

< 700

< 1000.

NS NS

< 270

<200

< 273

< 261

< 284

< 294

< 256

< 320

< 310 186

< 240

< 267

< 284 101D

<700

<1000 NS NS

<260

<210

<280

<276 137

<275

<258 250

<309

<295

<295

<276

<242 1OIS

< 700

< 1000 NS

< MDC

< 260

<210

< 284

< 278

< 284

< 273

< 255

< 350

< 255 233 166

< 271 252 102D 2,740 3,160 2,640 2,470 2,620 4,110 9,400 6,390 5,590 13,900 27,100 28,630 8,200 4,910 5,240 4,940 4,690 102S

<700

<1000

- NS 5,540 7,250 20,600 6,320 4,500 12,200 1,100 2,370 770 4,880 5,270 5,130 6,740 5,740 103D 22,180 17,550 19,660 20,900 20,800 8,100 12,900 13,400 12,900 10,100 10,300 11,460 10,500 9,130 9,060 12,000 6,530 103S 2,580 9,260 2,980 1,230 1,120 5,350 627 6,460 495 1,760 886 2,610 3,500 195 263 1,090 5,300 104S

< 700

< 1000 NS NS

< 270 186

< 273

< 261 293 142.

< 258 390

< 307

< 255 152 285 241 105D 4,590 2,450 3,030 2,150 1,360 2,110 1,780 1,510 2,060 2,390 854 1,400 905 1,240 1,170 953 1,280 105S 138,700 67,400 23,480 15,900 12,200 1,800 1,870 7,860 4,140 8,070 5,410 4,470 4,850 3,370 3,280 5,520 3,350 106D 3,320 1,590 5,830 1,810 1,450 14,200 1,730 1,630 2,610 1,430 1,120 1,310 1,590 1,090 1,340 1,110 1,520 106S 24,290 16,370 NS NS 780 2,130 2,450 1,130 514 1,500 2,330 1,550 332 752 784 542 850 107D

< 700

< 1000 NS

< MDC

< 270

<210 217 211 214 242 481 630 647 424 664 732 656 107S

< 700

< 1000 NS

< MDC

< 270 219 254 274

< 284

< 292 346 580

< 250 232 255 225

< 352 108S

< 700

< 1000 NS NS

< 270 156 290 221 256

< 291

< 251 240 206

< 287

< 283

< 268

< 251 109D 33,070 31,600 21,230 15,800 6,550 5,720 3,810 5,660 4,150 593 4,550 3,350

< 305 4,210 3,890 4,550 3,140 109S

<700

< 1000 NS

< MDC

< 270

<240

< 265

< 261

< 288

< 276

< 257

< 350

< 300

< 242

< 260

< 279

< 275 110D 27,630 23,280 27,230 18,300 18,700 21,300 16,500 10,700 15,200 11,100 4,630 5,310 11,300 6,620 6,550 5,890 8,300 110S 3,090

< 1000 2,470 2,360 1,890 3,270 2,980 1,470 2,390 2,050 1,430 1,370 1,420 1,290 1,090 2,050 1,010 Ills

<700

<1000 NS

<MDC

<270.

<210

<273

<259 222

<292

<253

<350 299

<278

<282

<269 233 112S

<700

< 1000 NS NS

<270

<240

<277

<259

<277

<293

<249

<340

<306 159 153

<272

<277 113S

<700

< 1000 NS NS-

<270

<240

<272

<263 160

<290 149

<340 118 215 181

<260 180 114S

< 700 1,180 2,850.

2,760 1,940 NS 3,730 1,140 1,190 927 1,530 1,070 481 1,280 1,610 1,350 6,730 115S

< 700

< 1000 NS 5,550 4,500 NS 1,870 4,090 1,900 2,180 2,230 3,410 NS 2,630 2,680 5,740 NS 117S.

<700

< 1000 NS NS

< 180

<240

<272

<261

<279

<294

<249

<340

<253

<255

<287

<283

<324 122D NI NI NI NI NI NI NI NI NI NI

< 258

< 360

< 305 120

< 237

< 298 222 122S NI NI NI NI NI NI NI NI NI NI 720 850 895 898 631 750 645 123S NI NI NI NI NI NI NI NI NI NI

< 260

< 340 128 201 228

< 249

< 306 124S NI NI NI NI NI NI NI NI NI NI 4850 4,350 4,340 1,910 2,020 1,530 1,770 125S NI NI NI NI NI NI NI NI NI NI 1,540 1,900 873 2,110 1,930 2,350 2,170 AST-1

< 700

<1000 NS NS

< 260 144 245 NS NS NS NS NS NS NS NS NS NS Mat 2,630 2,320 NS 2,890 NS NS NS 2,180 NS NS NS NS NS NS NS NS NS Sump TWA-

< 700

< 1000 NS NS

< 270

< 250

< 267 NS NS NS NS NS NS NS NS NS NS TW-3 NS NS NS NS NS

< 200 NS NS NS NS NS NS NS NS NS NS NS Notes:

Bold values are greater than EPA 4-mrem maximum contaminant level (MCL).

(<) Non-detect with minimum detection concentration (MDC).

87

Table 4-3: Tritium Concentrations (pCi/L) in Groundwater (continued)

Well ID Mar'99 Apr'99 Sep'99 Jun'00 Jun'01 Dec'01 Mar'02 Jun'02 Sop'02 Dec'02 Mar'03 Jun'03 Sep'03 Dec'03 Dec'03u Mar'04 Jun'04 TW-4 NS NS NS NS NS

<200 NS NS NS NS NS NS NS NS NS NS NS MW-1 NS NS NS NS NS

<200 NS NS NS NS NS NS NS NS NS NS 223 MW-2 NS NS NS NS NS 601 NS.

NS NS 229 NS NS NS NS NS NS

<397 MW-4 NS NS NS NS NS

<200 NS NS NS NS NS NS NS NS NS NS

<245 MW-13

<700

<1000 NS NS

<270

<240

<267 NS NS NS NS NS NS NS NS NS NS 200

<MDC

<MDC NS NS

<180 NS NS

<261 NS NS NS NS NS NS NS NS NS 201

<MDC

<MDC NS NS

<180 NS NS

<262 NS NS NS NS NA NA NA NS NS 202

<MDC

<MDC NS NS

<180

<210

<266 NS NS NS NS NS NS NS NS NS NS 203

<MDC

<MDC NS NS

<270

<250

<267

<263 NS

<329 NS NS NA NA NA NS NS 204

<MDC

<MDC NS NS

<180

<210

<266 NS NS NS NS NS NS NS NS NS NS 205

<MDC

<MDC NS NS

<180

<210

<264

<275 NS NS NS NS NA NA NA NS NS 206

<MDC

<MDC NS NS

<180

<210

<261

.NS NS NS NS NS NA NA NA NS NS 207

<MDC

<MDC NS NS

<180

<250

<259

<278 NS NS NS NS

<238 NA NA NS NS EOF NS NS NS NS NS

<210

<265 NS NS NS

<249 NS NS NS NS NS NS Supply EOF2

<700

<1000 NS NS

<270

<200

<270

<263

<285 NS NS

<340

<302

<246

<243

<265 196 Schmidt NS NS NS NS NS NS

<267 NS NS NS NS NS NS NS NS NS NS 502 NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS

<302 503 NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS

<303 504 NS

.NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS 276 505 NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS

<284 507D NS NS

• NS NS NS NS NS NS NS NS NS NS NS NS NS NS

<306 507S NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS

<292 508D NS NS NS.

NS NS NS NS NS NS NS NS NS NS NS NS NS

<270 508S NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS

<282 Notes:

Bold values are greater than EPA 4-mrem maximum contaminant level (MCL).

(<) Non-detect with minimum detection concentration (MDC).

(D) Indicates dissolved sample, all other results are for total sample.

(NI) Well not installed. (NS) Well not sampled. (NA) Well sampled but not analyzed.

88

C C

(

Table 44: Hard-to-Detect (HTD) Concentrations (pCi/L) in Groundwater Well ID SEvent C-14 Fe-55 NI-63 Sr-89 Sr-90 Tc-99 Pu-238 Pu239/40 Pu-241 Am-241 Cm243/44 MW-IOOD 2004 Q1 1 -

C0.173 MW-100S 2004 Q1 I

0.196 2002 Q3

< 8.22

< 15.10

< 0

< 0.583

< 10.80

< 0.134

< 0.134 7.40

< 0.131

< 0.132 MW-101D 2004 Q1

< 1.16

< 0.26 2004 Q2 c-

<1.23 2002 Q3 4.46

< 17.60

< 4.26 0.55

< 11.20

< 0.156

< 0.156 7.59

< 0.319

< 0.244 2003 Q1 0.38

< 0.284

< 0.284 6.77

< 0.254 0.194.

2003 Q2

<40

< 1.7 MW-1OIS 2003 Q3 0.33 2003 Q4 0.47 2004 Q1 c-

<1.2 c-

<0.298 2004 Q2 c-

<1.2 2002 Q1

< 8.06

< 6.71

< 3.51

<0.664

< 10.40

< 0.182

< 0.271

< 10.70

< 0.213

< 0.215 2002 Q2

< 7.85

< 8.32

< 2.84

<0.721

< 11.30

< 0.14

< 0.139

< 7.74

< 0.203

< 0.187 2002 Q3

< 8.57

< 11.40 4.67

<0.636

< 10.70

< 0.252

< 0.143 4.69

< 0.139

< 0.14 2002 Q4

< 8.08 4.14 3.42

<0.85 14.30

< 0.134

< 0.236 10.70

< 0.152

< 0.317 MW-102D 2003 Q1

<0.578

< 0.295

< 0.295

< 18.60

< 0.113

< 0.113 2003 02

<38

< 1.6 2003 Q4

<10.50

< 3.42

<1.25

< 9.01

< 0.168

< 0.168

< 9.5

< 0.15

< 0.151 2004 Q1 c-

<1.11 c-

<0.259 2004 Q2 0.93 MW-102S 2002 Q1

< 8.07 2.54

< 3.88

< 0.716

< 10.50

< 0.283

< 0.19

< 11.30

< 0.133

< 0.293 2002 Q2 7.32 14.20

< 2.89

< 0.716 9.75

< 0.178

< 0.208

< 9.3

< 0.0954

< 0.0959 2002 Q3

< 8.57

< 11.30 4.18

< 0.52

< 10.90

< 0.132

< 0.132

< 7.69

< 0.129

< 0.13 2002 04

< 8.08 10.30

< 3.8

< 0.644 17.90

< 0.139

< 0.246 11.60

< 0.121

< 0.121 2003 Q1

< 8.07 7.89

< 4.5 0.38

< 12.30

<0.133

< 0.133

< 9.88

< 0.116

< 0.117 2003 Q2

<37 1.08 2003 Q3 0.55 2003 Q4

<1.26

• Notes:

Bold values are greater than EPA 4-mrem maximum contaminant level (MCL).

(<) Non-detect with minimum detection concentration (WC).

89

CI Table 44: Hard-to-Detect Concentrations (pCi/L) in Groundwater (continued)

(.

Well ID Sample C-14 Fe-55 Ni-63 Sr-89 Sr-90 Tc-99 Pu-238 Pu239140 Pu-241 Am-241 Cm243144 E v e n t I__

2004Q1

<1.2

<0.36 2004Q2

<1.2 2002 Q1

<8.06 6.27

<3.74

<0.603

<10.40

<0.199

<0.199 9.03 0.69

<0.159 2002 Q2

<7.85 2.86

<2.78

<0.691

<11.40

<0.098

<0.0981

<7.78

<0.239

<0.24 2002Q3

<8.56

<21.10 8.01

<0.63

<9.89

<0.305

<0.305 5.27

<0.119

<0.12 2002Q4

<8.08 9.04

<3.93

<0.593

<12.30

<0.263

<0.148 14.70

<0.111

<0.111 MW-103D 2003Q1

<1.78

<0.238

<0.238 8.76

<0.112

<0.113 2003Q2

<43

<1.9 2003Q4 0.37 2004Q1

<150.0

<11.70

<6.41

<0.815

<11.90

<0.103

<0.103

<12.10

<0.121

<0.099 2004Q2

<73.50

<12.30

<11.80 1.26

<8.31

<0.414

<0.208

<11.40

<0.369

<0.349 2002Q1

<8.07 3.50 3.71 5.23

<10.40

<0.18

<0.121

<7.11

<0.149

<0.278 2002 Q2 5.46 4.96 3.38 15.30

< 11.20

<0.188

<0.221

<7.23

<0.0924

<0.156 2002Q3

<8.56

<11.90 6.57 3.81 9.64

<0.151

<0.266 7.08

<0.12

<0.121 2002Q4

<8.08 8.55

<3.7 5.57 19.00

<0.21

<0.119 14.50

<0.115

<0.116' 2003 Q1

<8.07 8.81

<10.60 6.75

<12.40

<0.149

<0.263

<9.58

<0.128

<0.128 MW-103S 2003Q2

<9.2

<9.7

<38 1.13

<0.23

<2.9 0.25 2003Q3

<31.70 30.50

<34.10 2.59

<9.5

<0.134

<0.134

<7.7

<0.411

<0.234 2003 Q4

<16.90 4.23

<3.24

<0.615

<8.81

<0.165

<0.291

<9.67

<0.214

<0.122 2004Q1

<170.0

<10.10

<6.46 2.27

<10.90

<0.041

<0.127 16.60

<0.0995

<0.218 200402

<11.80

<10.80

<13.80 1.34

<10

<0.23

<0.156

<14.50

<0.256

<0.248 200302

<44 3.14 2003 Q3 2.02 MW-104S 2003Q4 13.40 2.72

<3.56 0.86

<8.87

<0.127

<0.127

<7.25

<0.119

<0.119 2004Q1

<151.0

<10.30

<5.71

<0.685

<10.80

<0.125

<0.113

<14.60

<0.0921

<0.0923 2004Q2

<11.70

<11.60

<12.60

<.1.35

<8.94

<0.293

<0.178

<14.40

<0.19

<0.211 MWN-105D 2002 Q1

<8.07

<6.19

<3.48

<0.571 0.90

<0.221

<0.25

<8.84

<0.272

<0.242 2002Q2

<7.85 5.10

<0

<0.597

<11.30

<0.179

<0.101

<5.85

<0.247

<0.119 2002Q3

<8.56

<11.70 3.61

<0.738

<11.

<0.128

<0.128 5.77

<0.11

<0.11 Notes:

Bold values are greater than EPA 4-mrem maximum contaminant level (MCL).

(<) Non-detect with minimum detection concentration (MDC).

90

Table 4-4: Hard-to-Detect Concentrations (pCi/L) in Groundwater (continued)

(

WellD Sample C-14 Fe-55 NI-63 Sr-89 Sr-90 Tc-99 Pu-238 Pu239/40 Pu-241 Am-241 Cm243I44 W ell ID E v e n t 2002 04

<8.08 8.14 2.69

<0.596

< 12

<0.174

<0.174 12.50

<0.162

<0.0918 2003Q1 0.66

<0.184

<0.325

<11.20

<0.174

<0.175 2003Q2

<36

<1.5 2003 Q3

< 0.427 2003 Q4 1.33 2004 Q1

< 151.0

< 6.85

< 9.67

< 0.811

< 10.30

< 0.144

< 0.0804

< 12.30

< 0.0417

< 0.0417 2004 Q2

< 74.50

< 11.80

< 13.40 1.11

< 8.36

< 0.252

< 0.18

< 11.30

< 0.358

< 0.35 2002 Q1

< 8.07 4.40 2.95 122.

8.89

< 0.118

< 0.118

< 6.94

< 0.159

< 0.161 2002 Q2 7.02 11.20 2.48 116.

8.57

< 0.201

< 0.17

< 5.74

< 0.12

< 0.121 2002 Q3

< 8.57

< 11.70 4.35 101.

11.80

< 0.117

< 0.244

< 7.51

< 0.25

< 0.142 2002 Q4

< 8.08 13.40

< 3.83 83.3 9.96

< 0.127

< 0.295 6.70

< 0.118

< 0.209 MW-105S 2003 Q1 5.91 12.10

< 4.67 138.

< 12.50

< 0.116

< 0.116

< 7.46

< 0.132

< 0.133 2003 Q2

< 66

<10

<10

<43 181.6

< 5.6

< 0.27

< 3.6

< 0.32 2003 03

< 31.80 7.48

< 3.63 197.

6.06

< 0.48

< 0.271

< 16.60

< 0.234

< 0.236 2003 Q4

< 15.90 5.76

< 3.45 144

< 8.95

< 0.175

< 0.174 6.40

< 0.134

< 0.134 2004 Q1

< 152.0

< 7.77

< 5.51 91.80

< 10.20

< 0.085

< 0.085

< 12.50

< 0.129

< 0.142 2004 02

< 74.30

< 12.60

< 13.10 16.20

< 8.33

< 0.392

< 0.221 8.32

< 0.207

< 0.341 2002 Q1

< 8.08

< 6.68

< 3.6

< 0.597

< 10.40

< 0.133

< 0.197 5.52

< 0.177

< 0.178 2002 02

< 7.85 6.94 4.22

< 0.527

< 11.30

< 0.108

< 0.108

< 9.27

< 0.22

< 0.221 2002 Q3

< 8.57

< 9.7 3.82

< 0.546

<11

< 0.182

< 0.378 9.68

< 0.156

< 0.157 2002 Q4 5.92 13.90

< 3.86

< 0.624

<12.30

<0.119

< 0.21 15.40

< 0.108

< 0.108 2003 Q1 0.36

< 0.188

< 0.188

< 11.30

< 0.118

< 0.119 MW-1 06D' 20030Q2

<38

< 1.5 2003 Q3 0.80 2003 Q4 0.50 2004 Q1

< 151.0

< 8.78

< 6.61

< 1.17

< 10.10

< 0.137

< 0.178 12.10

< 0.218

< 0.234 2004 Q2

< 11.90

< 11.60

< 13.60

< 1.2

< 8.99

< 0.175

< 0.143

< 14.40

< 0.275

< 0.36 MW-106S 2002 Q1

< 8.07 0.80 0.90 8.38

< 10.50

< 0.137

< 0.203 5.27

< 0.172

< 0.174 2002 02 6.03

< 6.67 2.09 13.0

< 11.20

< 0.196

< 0.111 8.34 0.44

< 0.219 Notes:

Bold values are greater than EPA 4-mrem maximum contaminant level (MCL).

(<) Non-detect with minimum detection concentration (MDC).

91.

(.

Table 4-4: Hard-to-Detect Concentrations (pCi/L) in Groundwater (continued)

(

Well ID Sample C-14 Fe-55 Ni-63 Sr-89 Sr-90 Tc-99 Pu-238 Pu239140 Pu-241 Am-241 Cm243I44 2002 Q3

< 8.57

< 11.10 4.44 2.26

< 10.90

< 0.112

< 0.197 4.40

< 0.179

< 0.213 2002 04

< 8.08 14.10

< 3.79 9.35

< 12.30

< 0.133

< 0.133 12.20

< 0.158

< 0.0898 2003 01 14.40 7.54

< 4.75 13.50

< 12.30

< 0.105

< 0.105

< 9.36

< 0.126

< 0.127 2003 02

<96

<11

< 6.7

< 52 18.68

< 5.8

< 0.2

< 3.5 0.24 2003 Q3

< 31.70 4.99

< 3.62 3.71

< 9.3

< 0.169

< 0.169

< 9.59

< 0.143

< 0.255 2003 Q4

< 15.90

< 9.93

< 3.49 4.35

< 8.94

< 0.135

< 0.238

< 7.3

< 0.253

< 0.254 2004 Q1

< 151.0

< 8.42

< 5.72 1.21

< 11.10

< 0.145

< 0.0389

< 12

< 0.166

< 0.263 2004 Q2

< 11.80

< 11.50'

< 11.70 3.17

< 14.40

< 0.294

< 0.172

< 15.10

< 0.264 5< 0.342 2002 Q1

< 8.23 0.70 1.00

< 0.628

< 11.20

< 0.196

< 0.11 4.36

< 0.124

< 0.223 2002 Q2

< 7.84 0.50

< 3.11

< 0.6 8.25

< 0.091

< 0.0909

< 7.18

< 0.204

< 0.188, 2002 Q3

< 8.21

< 16.40 4.76

< 0.557

< 11.10

< 0.219

< 0.124 6.46

< 0.143

< 0.144.

2002 Q4

< 7.88

< 5.83

< 3.66

< 0.572

< 11.40

< 0.161

< 0.161 10.70

< 0.12

< 0.213 MW-107D 2003 Q1 4

M 10D 2003 02

<40

< 1.7 2003 Q3 0.33 2003 Q4

< 0.669 2004 Q1

< 1.23

<0.301 2004 Q2

< 1.2 2002 Q1 2002 02

< 7.85 8.73

< 0 0.26

< 11.20

< 0.159

< 0.159

< 9.13

< 0.0954

< 0.096 2002 Q3 4.10

< 15.40 3.02

< 0.593

< 11.30

< 0.12

< 0.12

< 7.84

< 0.127

< 0.266 2002 Q4

< 7.88

< 5.56

< 3.64 0.44

< 11.40

< 0.193

< 0.109 10.30

< 0.163

< 0.0924 2003 Q2--

0.54

< 0.329

< 0.186

< 11.90

< 0.219

< 0.124 M 0S 20030Q2

< 44

< 1.9 2003 Q3 0.36 2003 Q4 0.54 2004 Q1

< 1.37

< 0.373 2004 02 2.69 MW-108S 2003 Q4 0.63 Notes:

Bold values are greater than EPA 4-mrem maximum contaminant level (MCL).

(<) Non-detect with minimum detection concentration (MDC).

92

(

Table 4-4: Hard-to-Detect Concentrations (pCi/L) in Groundwater (continued)

C, Well ID Sample C-14 Fe-55 Ni-63 Sr-89 Sr-90 Tc-99 Pu-238 Pu239140 Pu-241 Am-241 Cm243/44 E v e n t 2004 Q1

< 0.887

< 0.0919 2004 Q2

<.1.4 2002 Q1

< 8.24 4.68 3.13

< 0.666

<11.40

<0.109

< 0.109 6.27

< 0.275

< 0.158 2002 Q2

< 7.85 3.89

< 2.95

< 0.495

<11.10

<0.152

< 0.152

<7.79

< 0.211

< 0.212 2002 Q3

< 8.56

< 9.22 4.91

< 0.568

< 11.10

< 0.213

< 0.12 4.28

< 0.257

< 0.124 2002 Q4

< 8.08 11.00

< 3.82

< 0.646 9.88

< 0.096

< 0.169 20.90

< 0.121

< 0.122 2003 Q1 MW-109D.

2003 Q2

=

<39

< 1.9 2003 Q3

< 0.39

.2003 Q4

< 15.90

< 9.34

< 3.56

< 0.497

< 9.77

< 0.293

< 0.293 9.51

< 0.162

< 0.163.

2004 Q1

< 1.01

< 0.373 2004 Q2

< 1.16 2002 Q1 4.70 9.90

< 3.94 0.90

< 11.40

< 0.108

< 0.108 4.45

< 0.159

< 0.161 2002 Q2

< 7.85 5.35

< 3.07 0.66.

< 11.40

< 0.182

< 0.242

< 9.91

< 0.1

< 0.17 2002 Q3

< 8.21

< 15.30

< 4.96 0.97

< 11.30

< 0.127

< 0.224 9.06

< 0.277

< 0.367 2002 Q4

< 8.08 11.10

< 4.12 0.90 11.20

< 0.173

< 0.203 13.20

< 0.131

< 0.233 MW-109S 2003 Q1 0.98

< 0.324

< 0.324

< 11.90

< 0.14

< 0.141 2003 02

<36

< 1.7 2003 Q3 0.69 2003 Q4 1.01 2004 01

< 1.11

< 0.369 2004 02 0.80 MW-110D 2002 Q1

< 8.24 5.06

< 3.99

< 0.562 10.50

< 0.21

< 0.118 3.78

< 0.183

< 0.164 2002 Q2

< 7.85 5.76

< 3.12

< 0.52

< 11.10

< 0.151

< 0.151

< 7.82

< 0.231

< 0.111' 2002 03

< 8.56

< 9.96 4.15 2.54

<11

< 0.121

< 0.121

< 7.06

< 0.286

< 0.288 2002 Q4

< 8.08 8.85

< 3.9

< 0.696 9.99

< 0.177

< 0.37 21.30

< 0.213

< 0.121 2003 Q1

< 0.551

<0.158

< 0.158

< 9.8

< 0.147

< 0.147 2003 Q2

< 37

< 1.7 2003 Q3 0.36 Notes:

Bold values are greater than EPA 4-mrem maximum contaminant level (MCL).

(<) Non-detect with minimum detection concentration (MDC).

93

(7.

CC Table 4-4: Hard-to-Detect Concentrations (pCi/L) in Groundwater (continued)

(7 Well ID Sampt C-14 Fe-55 NI-63 Sr-89 Sr-90 Tc-99 Pu-238 Pu239I40 Pu-241 Am-241 Cm243/44 E v e n t_

2003 Q4 0.45 2004 Q1 0.66

< 0.311 2004 Q2

<1.15 2002 Q1

<11 4.05 3.10 0.34 8.44

< 0.12

< 0.119 6.91

< 0.169

< 0.171 2002 Q2 4.19 10.60

< 3.07

<0.545 7.58

< 0.196

< 0.231

< 7.57

< 0.122

< 0.123 2002 Q3

< 8.57

< 10.60

< 5.32

< 0.683

< 10.80

< 0.134

< 0.237 4.12

< 0.13

< 0.131 2002 Q4

< 7.88

< 6.23

< 3.79

< 0.528

< 11.50

< 0.129

< 0.228 13.20

< 0.104

< 0.105 MW-110S 2003 Q---

0.32

< 0.242

< 0.241

< 15.10

< 0.116

< 0.117

• 20030Q2

< 39

< 1.6 2003 Q3

< 0.423 2003 Q4 0.44 2004 Q1

< 1.7

< 0.354 2004 02 0.69 2002 Q1

< 8.24 5.61

< 4.15

< 0.629 1.00

< 0.198

< 0.112 6.14

< 0.169

< 0.303 2002 Q2

< 7.85 4.48 4.14

< 0.722

< 11.30

< 0.089

< 0.0884

< 8.24

< 0.178

< 0.179 2002 Q3 MW-111S 2002 Q4

< 7.88

< 5.4

< 3.68

< 0.527

< 11.60

< 0.099

< 0.175 6.12

< 0.209

< 0.247 2003 Q4 0.35 2004 Q1

< 0.788

< 0.264 2004 02

< 1.11 2003 Q4 5.49 MW-12S 2004 Q1

< 0.765

< 0.0936 2004 Q2 0.70 2003 02

< 44

< 1.7 2003 Q3 0.58 MW-113S 2003 Q4 0.84 2004 Q1 0.37

< 0.248 2004 Q2 0.67 MW-114S 2002 Q1

< 8.07 4.84

< 3.61 3.63 7.14

< 0.187

< 0.125 5.81

< 0.247

< 0.168 Notes:

Bold values are greater than EPA 4-mrem maximum contaminant level (MCL).

(<) Non-detect with minimum detection concentration (MDC).

94

(.

(

c Table 44: Hard-to-Detect Concentrations (pCi/L) in Groundwater (continued)

Well ID Sample C-14 Fe-55 NI-63 Sr-89 Sr-90 Tc-99 Pu-238 Pu239I40 Pu-241 Am-241 Cm243I44 W elt ID E v e n t 2002 Q2

< 7.84 2.17

< 2.61 3.26

< 11.20

< 0.11

< 0.109

< 7.52

< 0.119

< 0.12 2002 Q3

< 8.56

< 10.70

< 3.93 1.45

< 11.10

< 0.462

< 0.261 7.83

< 0.125

< 0.126 2002 04

< 8.08 7.58

< 3.65 2.62 14.70

< 0.157

< 0.157 11.50

< 0.129

< 0.229 2003 Q1

< 8.07 7.43

< 4.67 16.60

< 12.30

< 0.253

< 0.143

< 11.20

< 0.214

< 0.122 2003 Q2

< 41

< 1.8 2003 Q3 0.73 200304 1.15 2004 Q1 3.92

< 0.259 2004 Q2

< 1.19 2002 Q1

< 8.07 7.19

< 3.89 3.85

< 10.60

< 0.165

< 0.245

< 9.5

< 0.183

< 0.274 2002 Q2

< 7.85

< 8.14

< 2.41 0.52

< 11.30

< 0.112

< 0.111

< 6.8

< 0.131

< 0.131-2002 Q3

< 8.56

< 11.90 3.39 2.40

< 10.90

< 0.202

< 0.201 11.60

< 0.232

< 0.132 2002 04

< 8.08

< 15.10

< 3.85 1.42

< 12.20

< 0.145

< 0.145 11.30

< 0.224

< 0.266 MW-115S 2003 Q1 1.33

< 0.146

< 0.146

< 9.29

< 0.226

< 0.128 2003 Q2

< 37

< 1.5 2003 Q3 2003 Q4 1.41 2004 Q1 1.64

< 0.198 2002 Q4 1.28 2003 Q1 1.41 2003 Q2

<45 1.40 MW-117S 2003 Q3 1.42 2003 Q4 0.77 2004 01

< 1.09

< 0.27 2004 Q2 0.79 MW-122D 2003 Q1

< 0.693

< 0.108

< 0.108

< 0.198

< 0.234 2003 Q2

<10

<11

<45 1.21

< 0.22

< 5.3

< 0.34 2003 Q3

< 0.398 2003 Q4 0.21 Notes:

Bold values are greater than EPA 4-mnrem maximum contaminant level (MCL).

(<) Non-detect with minimum detection concentration (MDC).

95

(

Table 4-4: Hard-to-Detect Concentrations (pCi/L) in Groundwater (continued)

(

Well ID Sample C-14 Fe-55 NI-63 Sr-89 Sr-90 Tc-99 Pu-238 Pu239/40 Pu-241 Am-241 Cm243I44 E v e n t_

2004 Q1 0.55

< 0.148 2004 Q2 3.29 2003 Q1 1.59.

< 0.122

< 0.216

< 7.5

< 0.0932

< 0.0935 2003 Q2

< 89

<10

<10

< 42

< 1.7

< 6.8

< 0.13

< 4.3

< 0.35 MW-122S 2003 Q---

1.24 MWI25 2003 04 0.81 2004 Q1 0.64

< 0.317 2004 Q2 0.57 2003 Q1 0.63

<0.186

< 0.186

< 11.10

< 0.122

< 0.122 2003 Q2

< 9.4

< 12

<40

< 1.6

< 0.15

< 0

< 0.33 2003 Q3 MW-I23S 2003 Q4 1.37 2004 Q1 0.87

< 0.284 2004 Q2

< 1.34 2003 Q1 0.49

< 0.163

< 0.163

< 10.10

< 0.201

< 0.114 2003 Q2

< 100.0

< 9.3.

< 7.7

<40

< 1.6

< 5.3

< 0.15

< 3.6 0.30 MW-124S 2003 Q4 0.54 2004 Q1

< 1.12

< 0.486 2004 Q2 1.33 2003 Q1 0.69

< 0.18

< 0.102

< 6.34

< 0.114

< 0.202 2003 Q2

< 100.0

< 9.7

< 7.9

< 42 1.41

< 5.7

< 0.27

< 5.4

< 0.36 2003 Q3 1.17 2003 Q4 6.51 2004 Q1 3.15

< 0.307 2004 Q2 1.78 MW-203 2002 Q1

< 8.24

< 5.97

< 4.22

< 0.48 13.90

< 0.187

< 0.105 3.50

< 0.254

< 0.145 2002 Q4

< 7.89

< 5.49

< 3.85

< 0.758

< 11.50

< 0.105

< 0.219 10.30

< 0.119

< 0.211 MW 207 2002 Q1

< 8.23 4.04

< 4.02

< 0.565

< 11.40

< 0.105

< 0.105 5.14

< 0.15

< 0.151 2003 Q3

< 31.70 12.10

< 16.10 0.44

< 9.52

< 0.223

< 0.52

<13

< 0.326

< 0.186 Notes:

Bold values are greater than EPA 4-mrem maximum contaminant level (MCL).

(<) Non-detect with minimum detection concentration (WDC).

96

(7 Table 4-4: Hard-to-Detect Concentrations (pCi/L) in Groundwater (continued) c Well IDSample C-14 Fe-55 NI.63 Sr-89 Sr-90 Tc-99 Pu-238 Pu239140 Pu-241 Am.241 Cm243/44 MW-208 2003 Q4

< 15.80 3.77

< 3.55 0.89

<10.10

<0.308

< 0.174

< 9.48

< 0.116

< 0.116 MW-1 2004 Q2 0.94 MW-2 2002 Q4.

< 7.89

< 5.72

< 3.83 0.41

<11.40

<0.176

<0.0998 11.20

< 0.175

< 0.0997 MW-2 2004 Q2

< 1.02 MW-3 2004 Q2

< 1.24 EOF-2 2002 Q1

< 8.24 5.56

< 4.03

< 0.539

<11.30

<0.118

< 0.118 5.70

< 0.137

< 0.139 EOF-2 2002 Q3

< 10.80 SUPPLY.

WELL B 20020Q4

<.7 Notes:

Bold values are greater than EPA 4-mrem maximum contaminant level (MCL).

(<) Non-detect with minimum detection concentration (MDC).

97

Table 5-1: Required MDC Values MDC Analysis

-e MDC Analysis C

AiaL)

Type (pCi/L)

Type Gross a 3

Gas Prop.

Ag-108m 50 kySpec.

Gross f 4

Gas Prop.

Cs-134 15 ySpec.

H-3 400 LSC Cs-137 15 zySpec.

C-14 200 LSC Eu-152 50

'ySpec.

Mn-54 50

'ySpec.

Eu-154 50

'ySpec.

Fe-55 25 LSC Eu-155 50

.ySpec.

Co-60 25 y Spec.

Pu-238 0.5 a Spec.

Ni-63 15 LSC Pu-239 0.5 a Spec.

Sr-90 2

GPC Pu-241 15 LSC Nb-94 50 y Spec.

Am-241 0.5 at Spec.

Tc-99 15 LSC Cm-243 0.5 a Spec.

Table 5-2: Field Duplicate Results for March 2004 Sample Duplicate Sample ID Analyte Concentration Concentration Units Ratio Residual Agreement

+ 2-a TPU 1 2-a TPU Boron 173 174

,Ig/L 1.01

+0.6%

MW-114S Gross (3 18.5 + 1.55 16.3 + 1.66 pCi/L 0.88

-11.9%

-1.9a H-3 1350h260 1570+ 266 pCi/L 1.16

+16.3%

+1.2a Sr-90 3.921 0.79 3.39 0.73 pCi/L 0.86

-13.5%

-1.Oa Table 5-3: Field Duplicate Results for June 2004 Sample Duplicate Sample ID Analyte Concentration Concentration Units Ratio Residual Agreement

+/- 2-a TPU 1 2-a TPU Boron 484 518 piglL 1.07

+7.0%

MW-l0SS Gross,6 44.3 z 2.7 43.2 h 2.7 pCi/L 0.97

-2.5%

-0.6o H-3 3350 + 263 3270 + 260 pCifL 0.98

-2.4%

-0.4a Sr-90

.16.2 L 1.71 16.8:L 1.73 pCi/L 1.04

+3.7%

+0.5a 98

Table 54: Lab Duplicate Results for March 2004 Sample Duplicate Sample ID Analyte Concentration Concentration Units Ratio Residual Agreement d2-r TPU

2-o TPU MW-106S Boron 670 635 pglL 0.95

-5.2%

MW-122D' Boron 224 223

1. g/L 0.99

-0.4%

MW-122D2 Boron 197 199

,ig/L

.01

+1.0%

MW-109S Gross j 9.63 + 1.02 8.06 + 0.96 pCi/L 0.84

-16.3%

-2.2a MW-113S Gross 16.3 + 2.07 13.7+2.05.

pCi/L 0.84

-16.0%

-1.8a MW-114S Gross 18.5 + 1.55 16.3 + 1.66 pCi/L 0.88

-11.9%

-1.9a MW-114S Rep.

Gross 16.3 t1.66 20.8k 1.85 pCi/L 1.28

+27.6%

3.6a MW-106S H-3 542 +/- 202 494 +/- 194 pCi/L 0.91

-8.9%

-0.3oa Table 5-5: Lab Duplicate Results for June 2004 Sample Duplicate Sample ID Analyte Concentration Concentration Units Ratio Residual Agreement 4 2-a TPU 4 2-a TPU MW-2 Boron 15.5 14.0 Itg/L 0.90

-9.7%

MW-108S Boron 68.3 68.7 Ig/L 1.00

+0.6%

MW-110S Boron 291 301 JgfL 1.03

+3.4%

MW-508S Boron 41.9 41.8 (Lg/L 1.00

-0.2%

MW-117S Gross /

7.28 + 1.55 8.65 -41.58 pCi/L 1.19

+18.8%

+1.2a MW-l10S H-3 1010+/-220 789k 171 pCi/L 0.78

-21.9%

-1.6a 1,

99

Table 5-6: DOE QAP Lab Performance Data Summary

Gamma Alpha Tof Sample Media Gam Alh HT T sotal Isotopic Isotopic Air Filter 96.6%

97.2%

100.%

96.9%

Soil 97.2%

97.7%

100.%

97.7%

Vegetation 100.%

100.%

85.7%

98.0%

Water 96.9%

97.2%

91.7%

96.2%

All Totals 97.4%

97.8%

94.3%

97.1%

Table 5-7: MAPEP Lab Performance Data Summary Gamma Alpha False Sample Media Isotopic Isotopic HTD Positive Total Water 100.%

96.0%

94.1%

60.0%

97.2%

Soil 100.%

96.0%

75.0%

80.0%

94.4%

All Totals 100.%

96.0%

86.2%

70.0%

95.8%

Table 5-8: ERA Lab Performance Data Summary for Water (ERA 52 - 55, 57)

Gamma Alpha HTD Total Isotopic Isotopic 96.2%

100.%

100.%

98.4%

100

Table 5-9: QC Summary for March 2004 Sample Event Sample Type Nuclide Tests Percent of Samples 692 77.4%

QC Blanks 49 5.5%

QC Lab Controls 55 6.2%

QC Matrix Spikes 49 5.5%

QC Duplicates 49 5.5 %

Sample/QC Totals 894 100.%

Table 5-10: QC Summary for June 2004 Sample Event Sample Type Samples QC Blanks QC Lab Controls QC Matrix Spikes QC Duplicates Sample/QC Totals Percent of Nuclide Tests Preto Total Samples 715 68.9%

79 7.6%

85 8.2%

76 7.3%

82 7.9%

1037 100.%

Table 5-11: Lab QC Acceptance Limits QC Category Duplicates Blank Spikes, Matrix Spikes Method Blanks GEL Acceptance Limits (%)

i 20%

4 25%

< CRDL.

Table 5-12: Internal Performance Data Summary (LCS, MS)

Method March 2004 June 2004 Total Boron 50.0%

75.0%

64.3%

'y-isotopic 100.%

100.%

100.%

ct-isotopic 100.%

100.%

100.%

LSC 92.9%

100.%

97.4%.

GPC 90.9%

100.%

95.8%

All Totals 91.4%

97.9%

95.2%

101

Table 5-13: Summary Statistics for March 2004

1. of Min.

Max.

Mean Sdev.

Median EPA Conc.>

Conc.>

Nuclide Method Sampes Conc.

Conc.

Conc.

Conc.

Conc.

MCL P

(pCUL)

(pCUL)

(pCUL)

(pCVL)

(pCi/L)

(pCUL) 2-cTPU MCL Gross a GPC Gross p GPC H-3 LSC C-14 LSC Mn-54 Y

Fe-55 LSC Co-60 y

NI-63 LSC Sr-90 GPC Nb-94 y

Tc-99 LSC Ag-108m y

Cs-1 34 y

Cs-I 37 y

Eu-152 y

Eu-154 y

Eu-155 y

Pu-238 a

Pu-239,240 a

Pu-241 LSC Am-241 y

Am-241 a

Cm-242 a

Cm-243,44 a

38

-0.164 11.30 2.126 2.525 1.290 15 38 0.778 203.0 17.68 43.40 6.135 50(S) 39

-59.9 12000 1771 2656 732 20000 12 11.9 140 72.32 40.97 84.55 2000 39

-2.12 2.64

-0.064 1.01

-0.12 300 12

-45.7 9.53

-21.32 20.43

-25.05 2000 39

-3.31 3.23 0.245 1.230 0.247 100 12

-5.23 0.483

-2.315 1.703

-2.575 50 37

-0.753 92.4 6.049 21.04 0.325 8

39

-1.27 2.78 0.457 0.935 0.453 12

-4.95 0.71

-2.020 1.658

-2.165 900 39

-2.27 1.84

-0.117 0.846

-0.18 39

-1.22 3.33 0.409 1.044 0.383 20000 39

-2.72 22.4 0.652 3.865

-0.068 200 39

-6.26 8.83

-0.166 3.452

-0.292 60 39

-7.34 4.74 0.002 2.498 0.292 200 39

-5.85 6.56

-0.015 2.758

-0.080 600 12

-0.0271 0.0778 0.0135 0.0289 0.0035 15 12

-0.0153 0.0311 0.0101 0.0121 0.0105 15 12

-2.42 16.6 3.254 5.681 1.99 39

-17.9 16.9

-0.447 6.182 0.342 15 40

-0.0863 0.11 0.0234 0.0488 0.248 15 13

-0.0265 0.0357 0.0035 0.0168 0

15 13

-0.089 0.0452

-0.011 0.0356 0

15 22 0

37 2

25 0

2 0

2 0

0 0

2 0

0 0.

15 2

3 0

0 0

2 0

2 0

3 0

3 0

0 0

0 0

0, 0

0 0

2 0

0 0

2 0

0 0

0 0

Totals 692 122 4

102

Tabie 5-14: Summary Statistics for June 2004

1. of Min.

Max.

Mean Sdev.

Median EPA C

Conc.>

Nuclide Method Conc.

Conc.

Conc.

Conc.

Conc.

MCL 2

TPU MCL Samples (pCVL)

(pCUL)

(pCUL)

(pCUL)

(pCUL)

(pCUL) 2 Gross a GPC Gross J GPC H-3 LSC C-14 LSC Mn-54 r

Fe-55 LSC Co-60 Y

Ni-63 LSC Sr-go GPC Nb-94 Y

Tc-99 LSC Ag-108m Y

Cs-134 Y

Cs-137 r

Eu-152 y

Eu-1 54 Y

Eu-155 Y

Pu-238 a

Pu-239,240 a

Pu-241 LSC Arn-241 r

Am-241 a

Cm-242 a

Cm-243,44 a

Totals 42 42 42 7

42 7

42 7

32 42 7

42 42 42 42 42 42 7

7 7

42 7

7 7

648

-0.24 28.8 3.24 4.78 1.74 0.23 44.3 7.22 7.81 5.12

-251.

8300.

1339.

2212.

222.

-14.7 3.53

-3.52 5.78

-3.61

-1.86 1.82

-0.05 0.76 0.00

-27.1 9.02

-10.6 15.7

-17.9

-1.17 11.4 1.23 2.32 0.48

-6.43 6.13

-0.55 4.92

-0.89

-0.24 16.2 1.29 2.86 0.62

-1.44 1.71 0.23 0.77 0.32

-7.78 0.56

-3.23 2.78

-3.40

-2.46 2.23 0.20 0.97 0.34

-1.75 3.84 0.40 0.99 0.40

-1.42 7.50 0.44 1.37 0.28

-7.03 4.12 0.29 2.38 0.36

-3.43 3.66 0.40 1.95 0.40

-5.68 6.45 0.42 2.95

-0.16

-0.064 0.067 0.020 0.047 0.025

-0.023 0.123 0.038 0.062 0.013

-8.25 8.32 0.012 5.46 0.000

-18.8 19.2 1.41 6.57 1.39

-0.045 0.090 0.012 0.049 0.003

-0.031 0.061 0.005 0.035 0.000

-0.088 0.064

-0.016 0.055

-0.004 15 20000 2000 300 2000 100 50 8

900 20000 200 60 200 600 15 15 15 15 15 15 27 39 24 0

0.

0 7

0 17 1

0 3

2 0

0 I

0 0

I 1

0 0

0 123 103

I Table 5-15: Limiting Mean Distribution Summary for March 2004 M

Limiting Limiting

1. of CacltdLimiting FliesCiia Nuclide ays Mean Sdev. Results tvalue Criticae Mean r-staustic r-staustic2 Distribution Method (YL pV) n)

tvle t-value Ba

-ttsi

-ttsi Gross a GPC 0.815 0.586 26 7.087 3.330 Positive 0.997 0.959 Normal Grossp GPC 1.750 0.569 8

8.696 4.530 Positive 0.988 0.905 Normal H-3 LSC 54.61 61.60 15 3.434 3.636 0.909 0.937 Non-normal C-14 LSC 72.32 40.97 12 6.115 3.850 Positive 0.963 0.926 Normal Mn-54 y

-0.306 0.725 35 2.500 3.236 0.978 0.968 Normal Fe-55 LSC

-43.0 3.182 4

-27.0 9.218 Negative 0.917 0.868 Normal Co-60 y

0.013 0.958 36 0.078 3.229 0.963 0.968 Non-normal Ni-63 LSC

-2.315 1.703 12

-4.709 3.850 Negative 0.984 0.926 Normal Sr-90 GPC 0.133 0.318 25 2.089 3.345 0.978.

0.958 Normal Nb-94 y

0.396 0.864 38 2.821 3.216 0.981 0.972 Normal Tc-99 LSC

-2.020 1.658 12

-4.222 3.850 Negative 0.993 0.926 Normal Ag-108m y

-0.168 0.793 37

-1.310 3.222 0.992 0.970 Normal Cs-1 34 y

0.332 0.939 38 2.178 3.216 0.987 0.970 Normal Cs-137 y

-0.303 1.025 34

-1.721 3.243 0.984 0.967 Normal Eu-152 y

-0.746 2.872 35

-1.560 3.236 0.990 0.968 Normal Eu-154 y

0.002 2.498 39 0.004 3.210 0.969 0.971 Non-normal Eu-155 y

-0.015 2.758 39

-0.035 3.210 0.991 0.971 Normal Pu-238 a

0.0135 0.0289 12 1.620 3.850 0.962 0.926 Normal Pu-239,40 a

0.0101 0.0121 12 2.876 3.850 0.978 0.926 Normal

\\

Pu-241 LSC 1.035 2.342 10 1.398 4.094 0.967 0.917 Normal Am-241 a

0.0234 0.0488 40 3.038 3.204 0.994 0.972 Normal Am-241 y

-1.236 5.238 37

-1.435 3.222 0.944 0.969 Non-normal Cm-242 a

0.0035 0.0168 13 0.754 3.764 0.969 0.931 Normal Cm-243,44 a

-0.0111 0.0356 13

-1.128 3.764 0.940 0.931 Normal Notes:

'Student t-statistic at the 99% Confidence Interval for n-i degrees of freedom 2Filliben's r-statistic at the 95% Confidence Interval for n degrees of freedom 104

Table 5-16: Limiting Mean Distribution Summary for June 2004 Nuclide Afnalysis Mean Sdev. Results Calculated Critical MeLimiting Filliben's Critical Nuld ea dV RslsMean D2 Dsribution Method (pCiIL)

(pCVIL)

(n) t-value t-valuel Bias r-statistic r-staisticF Gross a GPC 0.75 0.65 22 Gross GPC 1.30 0.66 9

H-3 LSC 99.3 126.6 26 C-14 LSC

-3.52 5.78 7

Mn-54

-0.14 0.65 40 Fe-55 LSC

-22.8 4.1 4

Co-60 y

0.43 0.74 36 Ni-63 LSC

-0.55 4.92 7

Sr-90 LSC 0.43 0.39 24 Nb-94 y

0.23 0.77 42 Tc-99 LSC

-3.23 2.78 7

Ag-108m 0.10 0.88 40 Cs-134 0.26 0.78 40 Cs-137 y

0.22 0.73 40 Eu-1 52 y

0.29 2.38 42 Eu-i54 y

0.40 1.95 42 Eu-155 y

0.42 2.95 42 Pu-238 a

0.020 0.047 7

Pu-239,40 a

0.038 0.062 7

Pu-241 LSC 0.01 5.46 7

Am-241

-0.16 5.14 37 Am-241 a

0.012 0.049 7

Cm-242 a

0.005 0.035 7

Cm-243,44 a

-0.016 0.055 7

5.388 3.400 Positive 0.970 0.954 Normal 5.963 4.277 Positive 0.973 0.912 Normal 4.000 3.330 Positive 0.964 0.959 Normal

-1.614 4.904 0.929 0.899 Normal

-1.366 3.204 0.989 0.972 Normal

-11.19 9.219 Negative 0.989 0.868 Normal 3.540 3.229 Positive 0.980 0.968 Normal

-0.296 4.904 0.965 0.899 Normal

.5.434 3.361 Positive 0.969 0.957 Normal 1.940 3.194 0.984 0.973 Normal

-3.073 4.904 0.982 0.899 Normal 0.748 3.204 0.971 0.972 Non-normal 2.102 3.204 0.968 0.972 Non-normal 1.891 3.204 0.987 0.972 Normal 0.795 3.194 0.959 0.973 Non-normal 1.345 3.194 0.991 0.973 Normal 0.920 3.194 0.986 0.973 Normal 1.148 4.904 0.957 0.899 Normal 1.588 4.904 0.936 0.899 Normal 0.006 4.904 0.992 0.899 Normal

-0.188 3.222 0.928 0.969 Non-normal 0.657 4.904 0.978 0.899 Normal 0.402 4.904 0.951 0.899 Normal

-0.748 4.904 0.986 0.899 Normal Notes:

'Student t-statistic at the 99% Confidence Interval for n-I degrees of freedom 2Filliben's r-statistic at the 95% Confidence Interval for n degrees of freedom 105

Table 5-17: Observed False-Positive Rates Analysis Type March 2004 June 2004 (GEL)

Average Rate (GEL)

Gamma Isotopic 4.3%

2.3%

3.2%

Alpha Isotopic 0.0%

0.0%

0.0%

HTD Beta via LSC 4.3%

1.9%

3.0%

Table 5-18: Data Quality Metrics Parameter Data Quality Metric Precision x Relative Percent Difference (RPD) < 20%.

• Laboratory Control Sample Recovery 100% +/-25 Accuracy MDC < 0.1

• Drinking Water Standard

• Laboratory Blank Analysis Results < MDC a Qualitative assessment of sample location, sample timing, Representativeness sample collection method, sample preservation, handling, shipment Completeness Valid measurements for critical samples = 100%

• Qualitative assessment of sample collection and measurement Comparability methods and assignment of sample locations to hydrostratigraphic units.

• Sample MDC < CRDL 106