SITE INFORMATION AND CORRESPONDENCE_1993-2003

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WASTE DISCHARGE REQUIREMENTS - 3 - DEFENSE DISTRIBUTION REGION WEST SHARPE INTERIM GROUND WATER CLEANUP SYSTEM SAN JOAQUIN COUNTY 7. In addition to the constituents reported in the above findings, bromacil, a herbicide, has been found in some of the ground water monitoring wells and may be present to greater or lesser degrees in the discharge. Sampling of the treatment system effluent for bromacil has been requested, however, sampling is not complete. 8. Monthly monitoring of the Discharger's effluent has either found the following constituents in the discharge or failed to test to sufficiently low levels of detection to alleviate concern. The constituents of concern are Aluminum, Antimony, Arsenic, Beryllium, Bromacil, Cadmium, Copper, Silver, Thallium, Vanadium, and Zinc. The discharge may have the potential to raise the receiving water constituent concentrations above acceptable Federal receiving water limits for these constituents of concern, thus creating a potentially toxic condition in violation of the Water Quality Control Plan. In absence of receiving water characterization, a study period is proposed to characterize the receiving water and amend the effluent limits as needed to include constituents that may pose a toxicity threat. 9. Since 1980, the Discharger has been conducting an environmental assessment of the site. The Discharger's studies showed that ground water in the southern portion of the DDRW Sharpe is contaminated with chlorinated solvents, up to 1,245 µg/1. There are elevated levels of arsenic, up to 720 4g11, in ground water. Off-site monitoring wells showed concentrations of chlorinated solvents as high as 200µg/1. Ground water degradation extends at least 140 feet deep on and off-site. Degradation in the northern portion of the facility is not completely defined. 10. Discharge of waste has impacted the beneficial uses of the area ground water which include domestic supply and irrigation. 11. The threat of further impacts on domestic supply and irrigation wells may be minimized by controlling the plume. 12. Since waste continued to migrate in ground water uncontrolled off-site, DDRW Sharpe, at the request of the Board, constructed an interim cleanup system designed to contain the plume of volatile organic compounds (VOCs) within a 100 µg/1 contour. The 100 4g/1 contour was defined (in Environmental Science and Engineering's 2 July 1985 report entitled "Draft Ground Water Remedial Action Plan for the South Balloon Area at Sharpe Army Depot(DDRW Sharpe)" as the area within which VOCs were 100µg/1 or higher. Construction of this system was completed in the spring of 1986. 13. On 24 January 1986, the Board adopted Cleanup and Abatement Order No. 86-038 (Order No. 86-038), requiring the Discharger to define the extent of its ground water pollution plume(s)by August 1987 and submit a remedial action report recommending a final cleanup action by December 1987. The interim treatment systems for the North Balloon Area and the South Balloon