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3 <br /> JM <br /> S. <br /> the data discussed herein, the writer does not bolieve this <br /> to be a factor that would necessitate the drilling of <br /> additional monitor wells. <br /> ANALYSIS OF WATER & SOIL SAMPLE DATA <br /> The water table is shallow at this site, about 25'-26' below <br /> ground level , which means that any spill of significance <br /> should penetrate the vadose zone and be found as floating <br /> product on the water table. No contamination was found in <br /> any water sample from any of the three monitor hells in <br /> either of the two samples, taken over one month apart. MW# 1 <br /> was located about 10' or so :From the contaminated soil <br /> sample found near the southerly and of the excavation. If a <br /> £'= significant spill had occurred, it is reasonable to assume <br /> that it would have migrated 10' laterally as well as 15' or <br /> 20' verticalll in the vadose zone, where hydraulic gradient <br /> is not a factor, to MW # 1 and it would have been observed <br /> ore. Perforations commence in M'{f #k 1 at 24' below the <br /> surface, the water table having been located at 25' to 26' <br /> below ground level by the driller. Subsequently, water was <br /> located about two or 3 feet higher by Del-Tech when <br /> measuring levels than the level found by the driller. This <br /> was prob._"ip owing to relatively low permeability and slow <br /> drainage to the well bore. Allowing for the recessed casing <br /> head, the top of perfs. in this well could be about 6" to 1" . <br /> below the standing water level. However, by bailing the <br /> wells down for samplirg, which we know happened, the water <br /> at the top of the water table would have beeii pulled into <br /> 1 <br /> the well and any product sampled. <br /> Wells 2 and 3 were completed with the perforations four feet <br /> higher. No contamination was found in any sample from either <br /> well . <br /> All soil samples from MW # 1 & 2 showed no contamination; <br /> however in MW # 3 an increasing amount of Toluene was found <br /> at 161 , 21' and 26' (.009, .010 and .032 mg/kg) . Yet none <br /> was detected in the water samples from this well, whose <br /> standing water level was about 23' below ground level, <br /> 5- according to Del-Tech measurements. This indicates that the <br /> V' water is rising in the well owing to hydrostatic head from <br /> sands lower than the area where the Toluene was found. The <br /> increasing amount of contaminant with depth indicates (to <br /> M' this observer) that the contaminant migrated downward from <br /> the surface. TMs is a reasonable hypothesis because the <br /> { entire area is used to store and repair trucks and other <br /> �. <br /> the_aspha.lt_covex was badly degraded_ <br /> in this area., which would allow easy access to the. vadose <br /> zone from surface spills. In any event, .the groundwater has <br /> not been impacted, and even if it.had been, the direction of . <br /> the water table gradient would not indicate any. possible <br /> connection to the contamination found at the site of the <br /> pulled tank. <br /> t, <br /> x 9 <br />