Laserfiche WebLink
utilizing EPA 8020 and 8015 methodologies, respectively The analytical results are summarized <br /> in Table 4 Laboratory data sheets and chain-of-custody documentation are included in <br /> Appendix VI <br /> 4.0 SUBSURFACE CONDITIONS <br /> Soils encountered beneath the project site consist primarily of lean to fat clays with apparent <br /> discontinuous layers of silt and sand The maximum depth explored was approximately 32 5 feet <br /> below grade <br /> No soil contamination was detected in any samples collected from the unsaturated zone Gray <br /> discoloration and xylene odors were noted in soils within the capillary fringe and saturated zone <br /> in Boring MW3, however, indicating that some soil contamination is present at the site <br /> Laboratory analyses of groundwater samples collected on March 3, 1992 from downgradient well <br /> MW3 exhibited elevated levels of ethylbenzene, total xylenes, and TPHG The ethylbenzene <br /> level in MW3 (1400 ppb) exceeds State Maximum Contaminant Levels (MCLS) for drinking <br /> water standards, as established by the California Department of Health Services (DHS) <br /> Constituents detected in the remaining groundwater samples included TPHG in MW1, toluene, <br /> ethylbenzene, xylenes, and TPHG in MW2, and a trace level of xylene in MW4 Monitoring <br /> wells MW5 and MW6 did not contain detectable levels of any analyte (Table 4) <br /> Groundwater was initially encountered in the borings at approximately 16 to 18 feet below grade <br /> and subsequently rose to approximately 16 feet below grade, suggesting that groundwater exists <br /> under semi-confined conditions The wells were monitored again on March 19, 1992 to verify <br /> monitoring data Based upon March 19, 1992 monitoring data (Table 5) static groundwater is <br /> approximately 14-15 feet below grade and flows to the southeast under a gradient of 0 020 ft/ft <br /> or 106 feet per mile A groundwater gradient map is presented on Figure 5 <br /> LCR492 rJL 7 <br />