ML20125D852

Submits Summary of Eia Efforts to Provide General Outline of Specific Tasks & Responsibility of Each in Assessment of Environ Impact of U Mill Tailing Dam Failure.United Nuclear Corp Encl

ML20125D852
Person / Time
Issue date:	12/07/1979
From:	Eadie G NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS)
To:	Scarano R NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS)
Shared Package
ML20125D850	List: IA-80-529, Forwards Summary Rept Re Eia Efforts of Various Federal Agencies.Requests Mod of Bnwl Contract to Expand Svcs & Complete Sample Tabulation ML20125D847 ML20125D852 ML20125D859
References
REF-WM-28 NUDOCS 8001160361
Download: ML20125D852 (9)

Text

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puta fi jo, UNITED STATES y $p,"+ c).:; }*e, NUCLEAR REGULATORY COMMISSION

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an s DEC 0 71979 MEMORAf'DUM FOR:

Ron A. Scarano, Chief Uranium Recovery Licensing Branch FROM:

Gregory G. Eadie Uranium Recovery Licensing Branch

SUMMARY

dFTHECHURCHROCKENVIRONMENTALIMPACT ASSESSMENT EFFORTS 1

The following summary is intended to provide a general outline of the specific tasks and responsible agency's involvement in the assessment of the environmental impact of the UNC Church Rock uranium mill tailings dam failure. 8 As of this date, in addition to New Mexico and Arizona's activities, at least four federal agencies are actually conducting some type of evaluation of the situation based mostly on their expertise or legislative mandate.

This outline is meant co add some perspective to these separate efforts, and hopefully will aid in the ultimate coordination of all these activities to provide for the collection and adequate review of all available and necessary information in order to insure the protection of the public health and safety. These efforts will supplement the on-going activities of UNC, as described in their letter dated September 12,1979 and per recommendations of the New Mexico Environmental Improvement Division (f:MEID)

(see Enclosures 1 and 2).

The general assessment work plan may be outlined as follows; with more specific descriptions of the various tasks included in the discussions:

Task I: Establish Soil Clean-Up Criteria Task II: Assess Existing Contamination Task III: Verify Soil Clean-Up Efforts Task IV:

Release Area for " Unrestricted Use" Task V: De' fine Continued Monitoring Prograts Task VI:

Issue Final Report Task I:

Establish Soil Clean-Vo Criteria

'he goal of this task was to establish acceptable soil / sediment radiological clean-up criteria which are protective of public health.

i response to a request by the State of New Mexico, and in ecoperation with

he i:MEID, acceptable levels of residual radioactive contamination of the soil

-J rediments of the affected areas of the Rio Puerco v,ere provided in the

' ~ T letter dated August 23,1979 (see Enclosure 3).

Based on an evaluation of 2e limited data available at that tire, it was concluded that an effective clun-up program could be conducted by evaluating the thorium-230 and radium-226

'centrations in soils / sediments. Acceptable clean-up levels were established u ae no greater than 30 pCi/g of thorium-230 and 10 pCi/g of radium-226.

90023002 3d.

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Ross A. Scarano Task II: Assess Existing Contamination The goal of this task is to determine the extent of contamination, both radiological and trace metal constituents, for all possible environmental pathways.

1) Soil / Sediment The areas of concern include the Rio Puerco and affected areas in both New Mexico and Arizona, plus background locations.

Specific details of this sub-task are described in the NMEID letter dated September 25, 1979 (see Enclosure 4). At that time, it was reque :ted that about 1400 additional soil samples from the affected areas should be collected under the direct supervision of NRC/NMEID personnel using a standardized sampling technique consisting of an 11 cm diameter disk of 5 cm depth.

l Radiological analfses of these solid samples were provided within a matter of days of sample c)llection by means of sophisticated radiation detectors operated on-site at the UN' Church Rock Mill complex by scientific personnel from the Battelle Pacific 'lorthwest Laboratories (BPNL) under contract to the NRC. This extensive soil sampling scheme was completed about October 12, 1979, and the review and interpretation of these analytical results should be accomplished by the end of January by the NRC, NMEID, and with the assistance of BPNL statisticians under contract to NRC (see Enclosure 5).

(The trace metal concentrations in affected soils is being evaluated by NMEID.) Also, the above radiological data has been provided daily to UNC in order to aid them in the identification of contaminated areas and to evaluate their soil clean-up efforts.

2) Surface and Ground Waters This sub-task is described in the EPA /IHS correspondence dated August 15, and October 18,1979 (see Enclosures 6 and 7). Surf ace water monitoring (in addition to UNC monitoring efforts) extends from the mine discharge area, past the mill site and down the Rio Puerco to Chambers, Arizona. This sub-task is scheduled for 35 weeks post incident (ending about mid-March,1980) and is being conducted by USEPA-Region IX, Arizona DOH and New Mexico EID. Ground water sampling is scheduled for about 68 weeks post incident, ending about October 1980, and is being conducted by the IHS, but with NMEID conducting its own monitoring program through mid-March 1980. At this time, it appears that no well sampling program has been established to monitor the local Navajo wells and indications are that several of these wells are presently being used for human consumption.

Also, local Navajo wells may be directly influenced by any contamina-tion resulting from the dam failure, and it would seem prudent that a special effort to sample such representative Navajo ground water wells should be initiated as soon as possible by the responsible acencies.

90023003

t Ross A. Scarano

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3) Airborne Particulates Air sa'mpling in the vicinity of the clean-up operations, plus routine sampling at a station near East Gallup has been conducted by NMEID. The documentation and results of this sub-task are not available at this time, and it has been indicated that NMEID will periodically collect additional air samples as deemed necessary.

4) Livestock This sub-task has been initiated as described in the NMHSD letter dated September 13,1979 (see Enclosure 8). The IHS has supervised the collection and slaughtering of 2 cows, 4 sheep, and 1 goat selected as representative of

" exposed" animals plus 1 cow and 1 sheep as " control" animals.

Radiological analyses are being performed at the USEPA Las Vegas Facility, but complete results are not expected until the end of December,1979. A preliminary evaluation of

, the suitability of local livestock for human consumption has been completed by NRC based on the limited data available at this time (see Enclosure 9).

The estimated total human dose from typical livestock ingestion appears to be less than 240 mrem.

Further evaluations by the IHS, in consultation with other health agencies, should be completed for both radiological and trace metal constituents, when the final data are available.

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5) Vegetation At this time, no supplemental vegetation sampling has been proposed; nor is it deemed necessary.

6) Gamma Radiation Surveys The ARMS flight of the Rio Puerco area was completed during the week of October 12, 1979 under an NRC contract. To date, no new information has been reported but when made available, this information will be incorporated with the soil sampling data as obtained from sub-task 1 above.

Since soil sample results. show essentially background levels of radium-226, and the extensive groundlevel gamma surveys reported by UNC also confirm only background exposure rates, no further gamma surveys are deemed necessary at this time.

7) Human Studies As indicated in the CDC Press Release dated September 25,1979 (see 0), six Navajo children, selected on the basis that they were among the maximally exposed pcpulation, showed no elevated levels of in, vivo radioactivity as determined by whole body counting techniques at LASL. Urine bioassay results are not available at this time.

No further human sampling has been proposed; nor

ce any deemed necessary.

l 90023004

s Ross A. Scarano Task III: Verify Soil Clean-Up Efforts The goal of this task is to define the extent and depth of soil / sediment contamination of the affected areas of the Rio Puerco in both New Mexico and Arizona, and to provide inventory estimates of the radioactivity removed and of the residual contamination. As described in Enclosure 5, the NRC and NMEID are presently involved in the collection, review, and interpretation of the soil /

sediment sampling program and this effort should be completed about the end of Janua ry. 1980. Also, a veriflation soil sampling program is to be established by the NMEID with the assistance of NRC, to document the actual condition of the area and to insure compliance to the ~ciean-up criteria.

Task IV: Release Area for " Unrestricted Use" The goal of this task is tg insure that residual contamination of soil / sediment in the affected arroyos will be protective of the public health and safety.

At this time, the soil / sediment clean-up criteria are 30 pCi/g for thorium-230 and 10 pCi/g for radium-226. However, preliminary data indicates that the radium levels are, on the average, less than 5 pCi/g. An evaluation of the radiolgical dose assessment models has been reported by the NRC (see Enclosure 11). Computer dose modeling estimates indicate that the maximally exposed individual would receive a bone dose of about 5.5 mrem per year if exposed for an entire year to resuspended dust with residual cotamination at the clean-up criteria levels.

However, until UNC has effectively completed the clean-up of all affected areas of the Rio Puerco, and upon verification by the NMEID of acceptable levels of residual contamination, it would seem prudent to continue to discourage the use of the Rio Puerco for domestic, irrigation or livestock watering purposes.

The " warning signs" should be removed only after the Rio Puerco has been released by the NMEID for " unrestricted use."

Task V:

Define Continued Monitoring Programs The goal of this task is to determine the need for any ne'

,nitoring program which would be required after the area has been r

.o unrestricted use.

As indicated above, the soil / sediment clean-up program do fully resolve the question of potential contr aination of the ground wate.., stem.

This can probably only be answered thrt.gh continued ground water monitoring over an extended time period beyond 1980. Such an effort should continue to be the responsibility of UNC with supplemental programs directed by NMEID, AZDOH, EPA, or IHS, as deemed necessary.

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t Ross A. Scarano The need for additonal soil / sediment or air sampling to monitor the actual contamination in the area post clean-up would best be determined after reviewing all pertinent data from sub-task 1 above.

Task VI:

Issue Final Report The goal of this task is to provide a final public report containing all available information regarding the environmental impact assessments made by all of the agencies involved.

Obviously, this task will require the cooperation of all parties, but the final report should be prepared and issued by the responsible regulatory agency, NMEID.

0 Gregory G. Eadie Uranium Recovery Licensing Branch Division of Waste Management cc:

H. May, EPA Region VI W. Stumpf, EPA Region IX F. Galpin, EPA D. Hendricks, EPA, LVF J. Womack, IHS, Gallup, NM K. Kreiss, CDC, Atlanta, GA T, Wolff, EID, Santa Fe, NM H. Tso, Navajo EPC, NM 1

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D+sion of United Nucfear Corporation PO Boa 3951 4801incian school Acac N E

1. UOC RESOURCES Corecany Alouaveraue. New Mexico 87190 Alevauerove. Ne a Menico 67110 Teeepene 505 265 4421 September 12, 1979

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e-Mr. Thomas E. Baca W 21; Jj g Director NM ENVIRONMENTAL IM%0VEMENT DIVISION

C:r's of;ee P. O. Box 968 Santa Fe, NM 87503

REFERENCE:

Uranium Tailings Dam Spill Church Rock Mill

Dear Mr. Baca:

C,n the morning of July 16, 1979, the tailings dam breached at UNC's Church Rock mill, releasing approximately 280 acre-feet of tailings solution and 1100 tons of tailings solids, which eventually flowed into the Rio Puerco and traces of the spill reached as far as Navajo, Ari::ena.

UNC Mining and Milling immediately initiated cleanup and monitoring operaticns and these are continuing to date.

UNC expects to be in compliance with the EID requirements as stated in your letter dated August 13, 1979.

Although tailings spills have occurred at other mill sites in the past, there are unusual aspects associated with this incident that warrant further study.

Now that the immediate and reactive cleanup effort has been largely accomplished, UNC intends to undertake a comprehensive monitoring, sampling and testing program.

We feel that it is essential that certain kinds of data be developed, not only to evaluate the present impact of the spill but also to provide reference points for future study.

Routine monitoring data collected prior to the spill, as well as data collected since the spill, will be used as baseline comparatives relative to the ongoing program described in the attachment to this memo.

We see several benefits in a monitoring-program of this kind, not only to UNC Mining and Milling, but also to other agencies or entities who may have need of this kind of information in the future.

As one example, we expect to greatly increase our ef ficiency in continuing cleanup operations as a result of this program.

90023007

P, age 2 UnC It is UNC's intent to implement this program, in its entirety, beginning on September 11, 1979.

We propose to give a full presentation of the program and results to date to the EID and other interested parties on or about September 21, 1979.

Should you have any questions, please contact my office by Monday, Sep'tember 17th.

As you can see, this is a very ambitious program and we would appreciate being made aware of any comments or suggestions about the implementation or procedures outlined herein prior to our investment of the many dollars and manhours which will be required.

Sincerely, l'3 g

ukL d H. J. Abbiss, P.E.

Vice President Environmental and Safety Servi ps Enclosure 90023008 w=

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