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UPDATE 27 4-22-94 <br /> RESULTS - WATER <br /> GROUND WATER GRADIENT <br /> The ground water gradient maps have been produced from <br /> measurements obtained on December 30, 1993 and February 16, 1994, <br /> see Figures 4A and 4B. <br /> Figure 4A, December 30, 1993 depth to water measurements were <br /> obtained when the vacuum system was on. This figure shows a <br /> depression or trough forming from MW5 towards MW2 . <br /> Figure 4B, February 16, 1994 depth to water measurements were <br /> obtained with the vacuum system being off since December 30, <br /> 1993 . These most recent measurements indicate the ground water <br /> elevation rising and a recharge to the area, with a ridge forming <br /> from MW7 towards MW5, see Table 2 <br /> TOTAL PETROLEUM HYDROCARBONS <br /> Floating Product: <br /> No floating product has ever been observed in any of the <br /> monitoring wells or borings at this site <br /> Dissolved Petroleum Hydrocarbons 2n Ground Water (EPA method 5030 <br /> TFH as gasoline) <br /> The February 16, 1994 ground water sample results show a <br /> continuance of below detection limits for gasoline petroleum <br /> hydrocarbons, benzene, toluene and ethylbenzene . MW5 has tested <br /> below 1 ppm for gasoline range hydrocarbons since the June 24, <br /> 1991 All other wells have tested below 1 ppm gasoline range <br /> hydrocarbons since the March 29, 1992 sampling. These analyses, <br /> when compared to those of December 15, 1991, substantiate the <br /> removal of hydrocarbons associated with the ground water, see <br /> Table 1 . <br /> Before vapor extraction, November 21, 1990, gasoline range <br /> hydrocarbons were detected in MW1 (2 mg/L) , and MW5 (31 mg/L) . <br /> BTEX in Ground Water (EPA method 602) . <br /> Analyses from the December 16, 1991 sampling round show that <br /> only MWl, MW2 , and MW5, had BTEXs, in very low concentrations . <br /> None of the wells contained BTEXs in the March 5, and June 2 , <br /> 1992 sampling, except MW5 The laboratory detected only benzene <br /> (1 2 ug/L) in MW1 and only the xylenes (4 . 1 ug/L) in MW5 in the <br /> September 11, 1992 . The December 7, 1992 sample results showed <br /> only MW5 to contain ethylbenzene (1. 2 ug/L) and xylenes (35 <br /> ug/L) Results from the most recent sampling (February 16, 1994) <br /> show only MW5 containing xylenes at 2 . 5 ug/L. Prior to this <br /> sampling MW5 was being utilized as a vapor extraction well . This <br /> Pulling of the contaminants to the well consequently increased <br /> concentrations The VES was turned off on December 30, 1993 and <br /> page3 <br />