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Page 4, K�%ikcv, 11131 5 1 4.3 Groundwater Gradient Based on the data obtained December 28, groundwater gradient appears to flow in an easterly direction (Figure 3 at a gradient ofabout ( g ) g bout 0.1 feet per 100 feet {0.1 ,o). 4.4 Evidence of Soil Contamination Slight hydrocarbon odors were noted in soil samples at 10, 15, and 20 feet in KF-1. PID readings of 85 and 38 ppm were measured in the latter two samples, and a reading of 88 ppm was recorded from a grab sample at 30 feet. No odors were present in samples from KF-2, but a PID reading of 10 ppm was measured in the sample at 20 feet, Laboratory results are presented in Appendix B and summarized in Table 3. Total petroleum hydrocarbons as gasoline (TPH-g) were not detected above reporting limits in'any of the soil samples, although Iow peaks were observed in three samples. Volatile aromatic hydrocarbons were detected in tour of the six samples at concentrations at or near the detection limits. 4.5 Evidence of Groundwater Contamination A strong gasoline odor 'vas present in KF-3 when it was purged and sampled, and a moderate " odor was noted in KF-I. Elevated concentrations of all target analytes (except total lead) were j detected during laboratory analysis of water samples from both wells (Table 2 and Appendix I3). No odor was evident in KF-2, although all analytes were detected above the minimum detection limits. The highest concentrations were present in KF-3, which is consistent with the strong odors present in this well and its location closest to both the tank facility and the adjacent Chevron site. I S.0 DATA ANALYSIS i S.I Extent of Soil Contamination The absence of detectable TPH-g and the low concentrations ofBTEX in soil samples imply that no major soil contamination was encountered during this investigation. The available data suggest that soil contamination is not extensive at this site. Rather than vadose-zone: percolation from a leaking tank, the detected aromatics may have been adsorbed on soil particles from contaminated groundwater during seasonal fluctuations in groundwater level. I 5.2 Extent of Groundwater Contamination Contaminated groundwater is evidently present beyond the portion of the site studied in this investigation. The elevated concentrations of petroleum hydrocarbons in KF-1 imply that groundwater contamination probably extends off site beneath theresidential property to the north. Groundwater is also likely to be contaminated beneath the Kwikee Foods building, The i, • i