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J U L 2 3 1930 <br /> E of E Pages i NVIRONMENTAL HEALTH <br /> CONTAMINATION PERMIT / SERVICES <br /> Soil <br /> The site geology indicated a relative uniform series of beds <br /> layered horizontally at the site . Therefore , we do not believe <br /> any bedding plane migration of the fuel took place therefore , <br /> most of its movement was vertical . Naturally there would have <br /> been some lateral movement due to advection during rainfall <br /> infiltration and minor interflowing . For the most part the <br /> contamination is located in the general area of the old <br /> excavated tanks and the old dispensing islands . We project , <br /> using our Electromagnetic Induction and well data, the <br /> extent of the contamination is located inside of the 100 mmho <br /> line which is shown with hatch marks on the Horizontal <br /> Contamination Map . <br /> Boreholes BM- 2 & 3 showed no soil contamination at all ; borehole <br /> BM- 1 had considerable contamination , and was contaminated dawn <br /> to the water table . However , no free product or scheen was <br /> noted on any of the samples . As expected higher concentrations <br /> of fuel were found in the finer-grained material owning to their <br /> greater porosity . <br /> Water <br /> The ground water shows hydrocarbons in all wells . The greatest <br /> amount is located in well BM- 1 . Although no free product was <br /> noted a high amount of Total Petroleum Hydrocarbon was found at <br /> this point , lesser amount were found in wells BM- 2 & 3 . The <br /> profile of the ground water plume is generally as would be <br /> expected from the measured hydraulic gradient . Since historical <br /> ground water data indicate a gradient different from the one <br /> measured at the site , it would be reasonable to expect the water <br /> flow direction to change from time to time . If this change is <br /> seasonal the migration distance from the site will not be great <br /> but more concentrated at the site . <br /> MITIGATION <br /> If , upon review by the San Joaquin Local Health District, the site <br /> requires mitigation , we believe it will be far to costly to <br /> excavate the contaminated soil and treat it properly . Possible <br /> approaches to a realistic mitigation plan will probably require <br /> soil vapor extraction and possibly ground water treatment . <br /> Yours Truly , <br /> John Cussen <br /> President <br /> Richard Merriam <br /> California Certified Engineering <br /> Geologist # 850 ( No Stamp Available ) <br />