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Manfing Lamson 4asodates <br /> D. Petroleum Hydrocarbons in „Groundwater <br /> The results of chemical analyses on groundwater samples are <br /> summarized in Table 2 and the lateral distribution of <br /> hydrocarbons are presented on Plate 5. In the most recent round <br /> of sampling, hydrocarbons were detected in MW-1, MW-8, MW-9, and <br /> MW-10. The highest concentrations were found in MW-9 and MW-•10, <br /> timmediately south of the store, with total petroleum hydrocarbons <br /> ' (TPH) concentrations of 37 parts per million (ppm) and 78 ppm, <br /> respectively. No detectable concentrations were found in samples <br /> from wells to the north, east, or west, or in any off-site wells <br /> (see Plate 5) . These observations, consistent with past analyses <br /> over five years, confirm that the plume has migrated very slowly <br /> as expected in the clayey soil . <br /> E. Petroleum Hydrocarbons in Soil <br /> The results of chemical analyses on soil samples are <br /> summarized in Table 3 . The lateral distribution of hydrocarbons <br /> in the vadose soil is presented in Plate 6. Hydrocarbon <br /> concentrations detected in the soil are generally found in the <br /> area immediately south and east of the store. <br /> Concentrations of TPH in excess of 100 ppm were detected <br /> within the upper 5 . 5 feet at 14W-5, P-A, P-B, P-4 , and P-5. The <br /> highest concentrations of TPH were found in samples collected <br /> ' from MW-1 at 5. 5 ft (1, 100 ppm) , P-A at 5 , 0 ft (1, 300 ppm) , and <br /> P-4 at 4 . 7 ft (1, 400 ppm) . These samples were collected at the <br /> capillary fringe area immediately atop the shallow groundwater <br /> zone. No detectable concentrations of gasoline hydrocarbons were <br /> 6 <br />