SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

Memo to Gregory Vaughn -2- b March 1989 water table to a depth of approximately 180 feet, and the lower zone; from approximately 180 to 220 feet in depth. If future hydrogeologic investigations indicate there are more than two distinguishable water-bearing zones, these zones must be clearly identified and described. Page 16 Monitoring wells SMW-1 and -2 were reported to be dry since April 1988. However, during the CME inspection in December 1988, these wells contained ground water and water level measurements were taken. This discrepancy should be clarified. Page 22 The ten remaining soils gas survey locations not initially proposed by Hargis, are to be determined on an analysis of the data obtained from the initial 30 survey locations . Hargis should also consider the results from the soil gas sampling survey performed by Scott Walker of the Regional Board, report dated 26 January 1988. Based on this report, additional survey locations should be between the foundry, B-5 and SMW-3, and near the shallow supply well . The elevated ion counts from Sample K-1 of the Regional Board report may be due, in part, to its position near the septic tanks leachfields and supply well . Additional soils gas survey points in the TCA disposal area east of Pond 2N are needed. Page 23 Two of the three deep soils borings should be relocated. One deep soil boring should be centrally located in the drainage area south of the galvanizing building to determine the vertical extent of contamina- tion. The soils samples from the drainage area should be analyzed for heavy metals. Additionally, a deep soils boring in Pond 2N should be installed and samples collected and analyzed to determine the vertical extent of contamination of volatile organic constituents. An alternate location for a deep soils boring is south of the main factory building near entrance to the silver plating laboratory. Soil samples should be collected to the saturated zone, but analyses of all samples, and in particular analyses for heavy metals, may not be necessary if elevated levels in the shallow portions decrease to background concentrations. Page 24 The number of surface soil samples to be collected to characterize background concentrations from along Alpine Avenue should be reduced. At least two additional soil samples to characterize background concentrations should be collected from the field in the western portion of the site. Hargis should also consider collecting additional background soil samples from the central portions of the site. Ana lyses for cyanide and purgeable halocarbons are not necessary as these compounds are not naturally occurring, and, therefore, nondetection would be considered background for these compounds. Page 25 The exploration borehole proposed location south of the main factory building should be moved further east and should be located near the recommended cluster site location on the east or southeast side of this building.