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LEVINE•FRICKE <br /> 10.5 Power Transmission Line Easement <br /> The composited sample of the eight samples collected along the <br /> power transmission line easement was analyzed for chlorinated <br /> herbicides using EPA Method 8150. <br /> 11.0 SITE GEOLOGY AND DEPTH TO GROUND WATER <br /> Geologic descriptions presented in this section are based on the <br /> lithologic data obtained from the seven boreholes drilled on' the <br /> Site during this assessment (WS-1 through WS-7) . <br /> The Site is underlain by alluvial sediments deposited in the <br /> flood plain of the Calaveras River. Shallow sediments encoun- <br /> tered during drilling operations consisted of stiff silty clays <br /> to clayey silts. Sandy clays were encountered at about six feet <br /> below grade at soil borings WS-1 and WS-3 . An approximately <br /> 2-foot-thick lens of peat was encountered at soil boring WS-4 and <br /> WS-5. <br /> Lithologic logs recorded during drilling of the soil borings are <br /> presented in Appendix B. <br /> Ground water was encountered in the borings at depths ranging <br /> from 6 to 15.5 feet below grade. The static depth to ground <br /> water was observed to range from 4 to 6 feet below grade. <br /> 12.0 RESULTS OF CHEMICAL ANALYSIS <br /> A summary of the analytes detected in the samples submitted for <br /> laboratory analysis is presented in Table 2 . A brief discussion <br /> of chemical analysis results is provided in the following <br /> sections. <br /> 12.1 Field Area <br /> The insecticide DDT and related compound DDE were detected in <br /> relatively low concentrations in the three of the five composited <br /> samples covering the field area of the Site (Figure 4) . The com- <br /> pound 4 ,4-DDT was detected in SBF, SBG and SBH at concentrations <br /> . of 0. 028, 0. 074, and 0. 07 parts-per-million (ppm) , respectively. <br /> The compound 2,4-DDT was detected at a concentration of 0.01 ppm <br /> in each of the same three samples. Finally, 4,4-DDE was detected <br /> in these three samples at concentrations of 0. 021, 0.041, and <br /> 0.028, respectively. These concentrations are all substantially <br /> below the Total Threshold Limit Concentration (TTLC) for DDT and <br /> related compounds (established by the DOHS for classification of <br /> materials as hazardous) of 1 ppm (J. Marshack, 1986) . According <br /> -16- <br />