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hydrocarbon concentrations are inside MW #14, and soil vapor <br /> concentrations extend only about 25' beyond MW #14, which is <br /> stili some 175 ' beyond your property. <br /> I also briefly reviewed the file on the Diamond Lumber problem <br /> located at 151 South Main, which would be to the west and across <br /> Main Street from your property. The file was rather skimpy, but <br /> apparently 3 monitoring wells were drilled near the intersection <br /> of Main Street and the So. Pac. RR tracks. Based on those <br /> wells, the groundwater gradient was to the northeast, in <br /> essentially the same direction as determined by the wells at <br /> Manteca Bean. Apparently there is both soil & groundwater <br /> contamination at that site, caused by an UST which was removed <br /> prior to duly, 1984. <br /> A workplan had been submitted in April , 1990, (no copy of it in <br /> the files I reviewed, ) but a response from the EHD staff stated <br /> that there was . . "significant contamination of soil & groundwater <br /> associated with the removed underground storage tank. . . " A new <br /> work plan was required to be submitted by March 15, 1991. I do <br /> not know if that deadline has been met; nothing in the material I <br /> reviewed to confirm or deny. <br /> The presence of these two active projects on either side of your <br /> property is most likely the reason why the EHD staff wants a <br /> monitoring well at this location. However, based on the gradient <br /> already established, any contamination that might have been due <br /> to the removed tank on your site should have been detected in the <br /> monitoring wells at Manteca Bean. Water analyses taken a year <br /> ago showed no such contamination, and levels of tested substances <br /> indicate the size of the plume is decreasing, especially in the <br /> direction away from your site. <br /> In addition, 8TI 's proposed remediation program will create a <br /> pressure differential towards the location of the removed tank at <br /> Manteca Bean. This would have the effect of causing groundwater <br /> beneath your property to be drawn towards the withdrawal source. <br /> If any contamination did exist under your site, it would move <br /> towards the north/northeast and should be detected by one or more <br /> of the existing monitoring wells. I do not believe that will <br /> happen, but it is a remote possibility. <br /> I will briefly summarize my observations and conclusions for your <br /> information; I will send a copy of this letter to Mr. Ross. <br /> CONCLUSIONS: <br /> 1. Two major soil & groundwater contamination sites exist close <br /> 2 <br />