ML20199B609

Forwards Characterization Rept for Union Carbide Spoils Area Tuxedo,Ny.Area Meets Criteria for Unrestricted Use

ML20199B609
Person / Time
Site:	05000054
Issue date:	10/22/1997
From:	James Adler CINTICHEM, INC.
To:	Youngberg B NEW YORK, STATE OF
References
NUDOCS 9711190040
Download: ML20199B609 (11)

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CIN71 CHEM, INC.

P.O. BUX B10 TUXEDO NEW YOFT< 10907 [914]351-2131 October 22,1997 Ms. Barbara Youngberg NYS Dept of Environmental Conservation 50 Wolf Road Albany, NY 12233

Subject:

Characterization Report for Union Carbide Spoils Area in Tuxedo, NY Dcar Ms. Youngberg:

Enclosed plosse find the referenced report. Based on our findings, this area now meets the criteria for unrestricted use.

If you have any comments or questions, please contact me at (914) 351-2236, or Mr. James McGovern at.(914) 3512131.

Very truly yours, oseph J. 2 er Manager, HSEA Enclosure, as stated cc: T. Dragoun, NRC C. Warren E. Abelquist, ORISE L. Feigenbaum R. Aldrich, NYS J. McGovern bggD T. Michaels, NRC J. Adler D. Orlando, NRC L. Glander >

Document Control Desk, NRC )

bec: F.C. Kentz, III t K. Magar 9711190040 971022 11pf PDR ADOCK t)5000054 P PDR

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e Characterization and Dose Assessment:

Union Carbide Spoils Area Page 1 of 10 CINTICIIEM CIIARACTERIZATION AND DOSE ASSESSMENT REPORT:

UNION CARBIDE SPOILS AREA

1. INTHODUCTION This report presents the final results of the sampling program that was performed in the vicinity of the " Union Carbide Spoils Area" (UCSA) located on the Cintichem site in Tuxedo, NY, Field sampling activities were conducted during the spring and summer of 1997. The data obtained was then used to assess the potential for exposure, if any, that could result from residual ra(ioactivity (uranium ore residues) that are contained in this area.

The following two sections present the results of the UCSA characterization and dose assessment program. The characterization data indicates that the UCSA met the radiological criteria for unrestricted use in all areas except the "flot Spot" area that had been identified previously. This liot Spot has since been remediated to background levels. No radiation exposures in excess of natural background c e expected to result from the UCSA.

2. UCSA CIIARACTERIZATION PROGRAM RESULTS Potentially affected soil within and around the suspect area of the UCSA was characterized by a sampling program conducted during the spring and summer of 1997 The characterization was performed in accordance with and as described by a sampling plan spproved by the New York State Department of Environmental Conservation '.

A total of 25 boreholes were drilled in or around the ncrthem section of the UCSA, Additionally, a background borehole was installed 86 raeters east-southeast of the known UCSA liot Spot. The locations of these boreholes are shown in Figure 1. Three of the borholes placed within the UCSA hit obstructions after a few feet. The other 22 boreholes were drilled completely Grough the expected thickness of the fill layer to the refusal on the original surface's boulder layer, The fill lyer appeared to have a maximum thickness of 12 feet. Five of the UCSA boreholes plus the background borehole were sampled by split-spoon.

This yielded 36 soil samples from the UCSA and one six-foot composite sample from the backgrotmd borehole.

Nineteen composite samples of the soil cuttings were obtained from 19 of the 20 other boreholes that were installed. All 26 boreholes were gamma-logged at one-foot intervals with

, a sodium-iodide scintillation detector, yielding 155 gamma spectra. The soil sampling results from the five boreholes that were split-spoon sampled are presented in Table 1, A through E.

I " Radiological Characterization Plar) for Union Carbide Spoils Area," issued by Cintichem, Inc.,

dated January 22,1997 l

• Characterization and Dose Assessment: Page 2 of 10 Union Carbide Spoils Area The soil sampling results from the 19 boreholes from which composite samples were obtained are presented in Table 2. The soil sample result from the background borehole is presented in Table 3.

The soil concentrations of the principal long-lived radionuclides originally found within the known Hot Spot (i.e., Ra ??6, U 238, U-235, and Th-232) were all found to be within the range of natural background found in the background borehole. The background concentrations (in pCi/gm) were found to be 3.75 for Ra 226,5.13 for U-238, <0.22 for U-235,1.78 for Th-232, and <0.047 for Cs-137 (a fallout background radionuclide). The maximum soil concentrations found within the five split-spoon sampled boreholes were 6.76 for Ra-226,12.15 for U-238,0.15 for U-235,1.7 for Th-232, and 0.88 for Cs-137. The mean concentrations for the 36 soil samples were found to be 3.3 for Ra-226,3.1 for U-238,0.11 for U-235,0.85 for Th-232, and 0.157 for Cs-137. These results are essentially no different than natural background, with the possible exception of the sample from Borehole No. 2 at the 720 to 719 foot elevation from which the maximum results for Ra-226, U-238, and Cs-137 were obtained.

Borchole No. 2 bordered the known llot Spot on its northern side. The excavation and removal of this llot Spot also inicuded the soil layer surrounding this borehole. As such, the resulting maximums would now be 4.54 for Ra-226,5.58 for U-238,0.15 for U-235,1.7 for Th 232, and 0.166 for Cs 137.

The soil concentration results for the 19 boreholes from which composite samples were obtained are also indistinguishable from that of the background borehole. The maximum

! concentrations found were (in pCi/gm) 4.17 for Ra-226,6.18 for U-238, <0.14 for U-235,1.7 for Th-232, and 0.039 for Cs-137. The mean concentrations for this group of samples were l found to be 2.39 for Ra 226,3.51 for U-238, < 0.107 for U-235,1.09 for Th-232, and 0.13 for Cs-137 Q gamma logging results for the 155 one-foot intervals were also found to be indistinguisnable from those obtained in the background borehole.

L This data indicates that there are no deposits of uranium ore residue present in the UCSA other than that of the initial llot Spot that was subsequently removed. Radionuclides of interest have only been found at levels similar to those of natural background. This is additionally supported by the degree of U-238 decay chain equilibrium (i.e., Ra-226 to U-238 ratio) that was found.

As can be seen from Table 4, the soil samples from the UCSA boreholes had mean ta-226 :

U-238 ratios of about 0.73. This is that same ratio found in the background borehole.

Samples of soil from the known Ilot Spot and uranium ore residues from Building No. 3 both had mean Ra-226 : U-238 ratios of about 1.33. This indicates that the radionuclides fo the boreholes do not originat from the uranium ore that was processed on site.

Soil from the known llot Spot was completely excavated and removed. This resulted in a hole 10 to 12 feet in diameter and approximately 4 to 5 feet deep. This excavation was then surveyed and sampled. The bottom and sides of the excavation were scanned with a sodium-

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Characterization and Dose Assessment:

Union Carbide Spoils Area Page 3 of 10 iodide scintillation detector and a beta / alpha contamination frisker to locate any potentially elevated areas. None were found. The excavation was then soil sampled and surveyed for gamma exposure rate, with locations shown on Figure 2. _Results are presented in Table 5.

The soil cor.centrations found were consistent with those encountered for the remainder of th:

UCSA and background boreholes with mean concentrations (in pCi/gm) of 3.28 for Ra-226, 3.32 for U 238,0.13 for U-235,0.79 for Th-232, and 0.29 for Cs-137. Gross gamma exposure rates (background inclusive) were found to range from 8 to 13 pRem/hr at one meter above the surface, with a mean of 9.9 pRem/hr.

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3. CONCLUSIONS The UCSA, with the Ilot Spot remediated, has been found to be at natural background levels for uranium ore residues. As such, no radiatio , exposures in excess of natural background are expected. This area meets the criteria for unrestncted use.

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Characterization and Dose Assessment:-

Uulon Carbide Spoils Area Page 4 of 10 4

TABLE 1 UCSA BOREHOLE SOIL SAMPLE DATA Section I-A Ground Level Elevation: 724 ft Borehole No. 2 Grid Coordinate: 395N, 72.5W.

Depth interval Soil Coriceritrets oCVgm

( feet ) Ra-226 U-238 U-235 Th-232 - Cs 137 724 723 1.71 2.04 < 0.10 < 0.25 0.14 723 722 0.83 1.50 < 0.08 0.69 < 0.113 722-721 2.52 4.75 < 0.id 1.03 0.097 721 720 4.07 6.01 < 0. 6 6 < 0.77 0.23 NSR = No sample 720-719 6.76 12.15 < 0.29 <1.12 0.88 recoveed 719-718 NSR NSR NSR NSR NSR 718 717 1.32 <1.46 < 0.08 0.81 < 0.08 R = Refusal on bedrock 717 716 NSR NSR NSR NSR NSR or boulder 716-715 2.56 2.57 < 0.12 1.10 0.021 715 714 NSR NSR NSR NSR NSR 714 713 NSR NSR NSR NSR NSR 713 712 2.32 2.13 < 0.03 1.40 < 0.21 712 R R R R R Moan 2.76 4.08 0.12 0.896 0.244 S.D. 1.89 3.65 0.08 0.348 0.26 Section 1-B Ground Level Elevation: 722 ft Borchole No. 4 Grid Coordinate: 402N, Jaw Depth Interval Soil Concentration. oCUgm

! ( feet ) Ra-226 U-238 U-235 Th-232 Cs-137 722 721 1.71 3.56 < 0.11 1.31 < 0.08 721 720 2.35 3.94 < 0.11 0.79 < 0.08 720-719 2.61 2.84 < 0.11 <0.42 < 0.025 719 718 1.62 <1.69 < 0.04 0.64 < 0.088 NSR = No sample _ 718-717 1.65 2.17 < 0.10 0.89 0.14 recovered 717 716 NSR NSR NSR NSR NSR 716-715 2.0 2.49 < 0.08 0.83 0.10 R = Refusal on bedrock 715-714 NSR NSR NSR NSR NSR or boulder 714-713 NSR NSR NSR NSR NSR 713-712 NSR NSR NSR NSR NSR l 712 711 NSR NSR NSR NSR NSR 711 710 4.54 6.19 < 0.19 < 0.58 < 0.09 l 710 R R R R R i Mean 2.35 3.27 0.11 0.78 0.086 L

S.D. 1.03 1.50 0.045 0.284 0.034

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4 - 1 Characterization and Dose Asseasment:

Union Carbide Spoils Ares -

e, Page 5 of 10 TABLE 1 Continued

. Section 1-C Ground Level Elevation: 723 ft llorehole No. 6 Grid Coordinate: 400N, 87W Depth Interval Soil Corswi;rtucci. pCilgm

( feet ) Ra-226 U-238 U 235 Th 232 Cs 137 723-722 2.10- 2.88 < 0.11 1.35 < 0.078 722-721 1.65' 1.54 < 0.08 0.81 0.18 721 720 2.70 4.19 < 0.11 0 83 < 0.10 720 719 <1.22 <1.89 < 0.11 1.08 0.19 -

719 718 2.75 5.58 < 0.14 1.11 < 0.14

• R = Refusal on bedrock 718-717 1.2 1.78 < 0.08 0.54 0.17 or boutier 717 716 ' 2.22 3.06 < 0.11 < 0.29 < 0.09 116 R R R R R Mean 1.98 2.99 0.11 0.86 0.135 S.D. 0.643 1.47 0.02 0.36 0.046 Section 1.D Gidund Level Elevation: 724 ft llorehole No. 8 Grid Coordinate: 394N,85W Depth Interval Soil Concentration. DCl/9m

( feet ) Ra-226 U-238 U 235 Th-232 Cs-137 l 724 723 0.89 1.13 <0.07 < 0.17 0.135 723 722 1.01 2.01 < 0.07 - 0.96 < 0.063 722 721 2.10 5.02 < 0.12 1.06 0.17 721 720 0.96 1.43 < 0.04 0.73 < 0.076 720 719 0.93 1 43 < 0.08 0.57 0.087 719-718 1.33 2.27 < 029 0.89 < 0065

!' R = Refusal on bedrock 718-717 1.05 1.83 < 0.07 < 0.28 < 0.033 or bovider 717 716 1.48 2.19 < 0.07 0.68 < 0.08 l

716-715 1,98 2.39 < 0 *.1 0.91 < 0.07 715 714 1.35 1.68 < 0.09 0.67 0 01 714 R R R R R Mean 1.31 2.14 0.08 0.692 0.08 S.D. 0.435 1.09 0.023 0.29 0.046

Characterization and Dose Assessment:

Union Carbide Spoils Area - Page 6 of 10 TABLE 1 Continued Section 1-E Ground Level Elevation: 726 ft Borehole No.15 Grid Coordinate: 387.5N, 92.5W

' Depth Interval Soil Concentrabon. DCilam

( feet ) Ra-226 U-238 U 235 - Th-232 Cs-137 726-725 3.03 2.91 - < 0.11 1.07 0.48 725-724 2.22 3.25 < 0.12 < 0.05 0.66 R = Refusal on bedrock 724-723 3.91 2.58 < 0.16 1.70 0.095 or boulder 72377' 4.16 4.95 0.15 1.59 0.134 72l R R R R R Mean 3.33 3.42 0.135 1.22 0.34 S D. 0.885 1.05 0.024 0.55 0.27

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- Characterization and Dose Assessment:

Union Carbide Spoils Area Page 7 of 10 TABLE 2 UCSA BOREHOLE COMPOSITE SOIL SAMPLE RESULTS Borehole Grid Ground Bottom DCilgm ID No. Location Elevation (ft) Elevation (ft) Ra-226 U-238 U-235 Th-232 Cs 137 1 394N, 75W 724. 712 1.57 <1.76 < 0.086 1.58 < 0.04 3 398N, 76W 721 714 3.27 4.91 < 0.14 1.7 0.27 5 (no sample recovered) 7 397.5N, 90W 724 712 2.08 3.34 < 0.13 0.76 < 0.14 9 392.5N, 88W 724 716 2.64 5.48 < 0.11 1.3 < 0.06 10 395N, 83W 725 721 2.11 3.64 < 0.11 < 0.33 < 0.078 11 396N, 78W 724 715 3.52 6.18 < 0.13 0.58 0.19 12 392N, 78W 724 716 2.33 1.71 < 0.09 1.26 < 0. 05 13 392N, 82W 724 717 1.80 2.84 < 0.12 1.35 0.17 14 392.5N, 92.5W 726 720 2.19 5.38 < 0.12 1.42 0.18 16 385N, 93Y' 726 720 1.73 3.02 < 0.08 1.45 < 0.08 17 384N, 89W 724 718 2.70 5.00 < 0.12 1.35 < 0.065 18 396.5N, 89W 724 721 1.20 1.68 < 0.065 0.53 0.39 19 385N, 86W 725. 723 2.41 2.75 < 0.10 1.14 0.15 20 - 391N, 89W 725 724 3.50 4.56 < 0.11 1.36 < 0.065 21- 395N, 88W 725 718 NSR NSR NSR NSR NSR 22 385N, 75W 727 718 1.42 2.09 < 0.06 1.38 0.11 23 366N,134W 736 731 2.66 2.88 < 0.12 < 0.42 0.26 24 380N,126W 735 729 1.76 2.35 < 0.097 < 0.14 < 0.079 '

25 368N.116W 734 727 4.17 3.55 < 0.12 1.61 < 0.024

-Mean 2.39 3.51 0.107 1.09 0.13 S.D. 0.808 1.42 0.02 0.49 0.097 TABLE 3 UCSA HACKGROUND HORElIOLE DATA

• Soil Concentration " (pCi/gm)

Ra-226 U-238 U-235 Th-232 Cs-137 3.75 5.13 < 0.22 1.78- < 0.047

• Located approximately 282 feet (800 meters) east-southeast of the USCA ' Hot Spot *, at grid coordinato 342N,10W

" This borehole was sampled from ground level (730 ft) to a depth of 6 feet. The data represents a composite of the O to 6 foot borehole interval.

- Chbract:rization c:d Dose Assessm::t:

Union Carbide Spoils Area Page 8 of 10 TABLE 4 COMPARISON OF URANIUM 238 DECAY CIIAIN EQUILIBRIUMS FROM VARIOUS SOURCES Ra-226 to U-238 No. of Standard Sample Group Samples Range Mean Deviation Background Borehole 1 n/a 0.73 n/a Boreholes: 2, 4, 6, 8 & 15 (split spoon sewed) 36 0.41 1.52 0.738 0.224 Boreholes: 1, 3, 7, 9,10 14,16 25 (single composite sample) ill 0.41 1.36 0.73 0.24 Pre-R mediation Hot Spot Area 3 1.24 1.47 1.33 0.12 Post-Remediation Hot Spot Area (Excavated) 9 0.60 - 1.31 0.973 0.255 Bldg 3 Exhaust Ventillation Debris 3 1.067 1.84 1.34 0.43 TABLE 5 UCSA SOIL SAMPLE AND DutECT EXPOSURE RATE DATA FOLLOWING REMEDIATION OF IIOT SPOT

• Sample Gross Gamma Exposure Rate Soil Concentration, pCi/gm Location at 1 Meter ( Rem /hr) Ra 226 U-238 U-235 Th 232 Cs-137 l 1 8 1.76 1.78 < 0.09 0.94 < 0.06 2 8 1.65 2.28 < 0.104 1.09 < 0.08 3 10 1.09 0.86 < 0.06 < 0.21 0.091 4 9 9.74 7.44 < 0.23 < 0.25 0.37 5 10 3.2 3.16 < 0.14 1.46 0.37 6 13 1.86 2.26 < 0.12 < 0 29 0.34 7 10 2.3 3 84 < 0,12 1.74 0.15 8 10 3.66 3 01 < 0.14 < 0.55 0.62 9 11 4.22 5.24 - < 0.19 < 0.61 0.55 Mean 9.9 3 28 3.32 0.13 0.79 0.29 S.D, 1.54 2.63 1.99 0.05 0.55 0.21 This excavation removed the initial uranium ore contamination that was discovered in the UCSA. This is a 10 12 foot diameter excavation centered on or about grid

coordinate 391N,72W

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