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1997 Annual Report <br /> Sharpe Facility 6 10 February 1998 <br /> a.) Page 2-4 Section 2.5.3.6 Identifies a mound in the water table in piezometers P-5A, P513 and <br /> PSC. The Report does not explain why this mounding is occurring. These piezometers are <br /> located in the area of VOC Site P-IF. Since these piezometers have never been sampled for <br /> VOC concentrations, and the cause for higher water levels in this area is unexplained, we request <br /> m to bettrmin <br /> er dete <br /> that these piezometers be added to the ground water sampling prograe what <br /> is occurring in this portion of the South Balloon and verify the decision for no action <br /> respect to VOC contaminated soils. with <br /> b.) Bromocil has been used as an herbicide at Sharpe. Degradation of the groundwater has <br /> occurred from this usage as seen reported in this document that all seven wells analyzed had <br /> concentrations greater than the reporting limit, two of the seven well sampled for bromocil had <br /> concentrations exceeding 100 ug/I and concentrations in MW409A have shown an increase <br /> concentration in bromocil since 1996. Therefore, the nature and extent of the bromocil plumes <br /> in the groundwater should be defined. Use of existing monitoring wells should be sufficient to <br /> cant' out this requirement. <br /> c.) Inclusion of extraction well data lead to identification of a two new VOC plumes, one in the <br /> South Balloon and another in the Central Area. Similarly, as part of the investigation and <br /> cleanup of inorganic metals extraction wells in the source areas should be sampled and analyzed <br /> for lead and chromium. Extraction wells; EWA7, EWA8, EWA9, EWAIO, EWBI and EWNAI <br /> should sampled and analyzed for lead and chromium on a semi-annual basis during cleanup and <br /> investigations in the North and South Balloons. <br /> d.) Selenium has not been proposed for further groundwater sampling. Page 5-5, section 5.4.2.4 <br /> acknowledges that the Central Area A train effluent did not meet discharge requirements for <br /> selenium. Results from all thirteen wells sampled I 4Q96 were greater than ROD baseline <br /> concentrations. Additional samples for determination of background levels of selenium will <br /> need to be collected for this facility. <br /> If you have questions or comments regarding this letter, please call me at(916)255-3051 or Karen <br /> Bessette at(916) 255-3065. <br /> CORICONDON <br /> Associate Engineering Geologist <br /> cc: Mr. Michael Wolfram, U.S. Environmental Protection Agency, Region IX <br /> Ms. Hortensia Muniz, Dept. of Toxic Substances Control, Sacramento <br /> Mr. Michael Williams, U.S. Corps of Engineers, Huntsville, Alabama <br /> Mr. Harlan Knoll, San Joaquin County Environmental Health Department <br /> Mr. Bob Pico, Technical Review Committee Member, French Camp <br />