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1 � � <br /> due to relatively high concentrations of MTBE in the samples collected from those wells (as described <br /> below). Benzene and TPH-G were not detected at or above raised detection limits and TEX constituents <br /> 11 were detected ranging from 3.6 µg/1 to 43 µg/1 in the sample collected from MW-2. MTBE was detected <br /> at 110,000 µg/1 in the MW-2 sample. BTEX and TPH-G were not detected at or above the laboratory <br /> reported detection limits in the sample collected from MW-3. MTBE was detected at 1,900 µg/I in the <br /> MW-3 sample. TPH-G was detected at 0.52 mg/1 and BTEX constituents were detected ranging from 1.5 <br /> µg/1 to 100 µg/1 in the sample collected from MW-4. MTBE was not detected at or above the laboratory <br /> reported detection limit in the MW-4 sample. No floating product, sheen, or petroleum hydrocarbon <br /> odor was noted in the monitor wells. <br /> Laboratory analytical results of the groundwater samples for the first quarter, 1998, monitoring event <br /> ' were generally consistent with the historical quarterly groundwater analytical data. MTBE <br /> concentrations in samples from MW-2, however, have increased by more than two orders of magnitude, <br /> total, during the three quarterly monitoring events conducted at the site. <br /> Groundwater elevation measurements collected at the site on March 27, 1998 indicated that the average <br /> depth to groundwater was approximately 5 feet bgs. The average depth to water at the site increased by <br /> approximately 1 foot between December 31, 1997 and March 27, 1998. Groundwater elevation contours <br /> estimated using the depth-to-water measurements collected on March 27, 1998, indicated that <br /> groundwater gradient at the site is generally consistent with the estimated gradient on September 18, <br /> 1997, and December 31, 1997. <br /> In a telephone conversation on March 23, 1998, Mr. Ronald Rowe of the San Joaquin County Public <br /> Health Services/Environmental Health Department (PHS/EHD) indicated that upon his review of the <br /> above referenced report, dated December 11, 1997, that he was requesting quarterly groundwater <br /> monitoring continue at the site and that a work plan should be prepared for conducting quarterly surface <br /> water sampling and further investigating the gasoline oxygenate/additive plume to the east of site <br /> monitor well MW-2. Condor prepared a letter, dated March 23, 1998,documenting the conversation. <br /> 1 <br /> 1 <br /> 1 <br /> 1 <br /> 1 <br /> 1 <br /> 1 <br /> I B_6 <br />