SITE INFORMATION AND CORRESPONDENCE

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Mr. Mike Infurna April 3, 1995 (9347-9046) Aegis Environmental, InJJ��. (Aegis) personnel supervised the drilling and sampling of ten soil borings on site in January�'1990. The borings ranged in depth from 11.5 to 21.5 feet below surface. Laboratory analysis of soil samples collected from the borings did not indicate total petroleum hydrocarbons (TPH), as gasoline, or benzene, toluene, ethylbenzene, and total xylenes (BTEX) above the respective PQL. Results of the investigation were documented by Aegis in the "Pre-Tank Replacement Site Assessment Results Report", dated April 13, 1990. On January 18, 1994, Aegis personnel supervised the drilling of three on site soil borings to approximately 22 feet below surface and one HydroPunchTm boring to 13 feet below surface. Static groundwater was encounterept approximately 12.5 to 14 feet below surface. The soil borings were completed as 4-inch✓diameter groundwater monitoring wells MW-1, MW-2, and MW-3. The results of the investigation were documented by Aegis in the "Site Investigation/Monitoring Well Installation Results Report", dated April 18, 1994. Laboratory analysis of soil samples collected from the borings did not indicate total petroleum hydrocarbons, as gasoline, or benzene above the respective PQL. The groundwater sample collected from the HydroPunchTm boring did not contain TPH, as gasoline, or BTEX compounds above the respective PQL. Previous Quarter's Activity The NET Laboratory (NET) analytical report stated the groundwater sample collected from well MW-3 on November 10, 1994 contained 0.320 ppm TPH, as gasoline, but noted a chromatogram pattern not typical of gasoline. Per the request of Mr. Mike Infurna, Fugro faxed the laboratory chromatograms for well MW-3 to the San Joaquin County Public Health Services, Environmental Health Division. The groundwater sample collected from MW-3 on February 21, 1995, was analyzed for petroleum hydrocarbons by EPA Method 8020, and for petroleum and chlorinated hydrocarbons by GUMS Method 8240. All compounds in the GUMS 8240 analysis, including BTEX, were below the respective laboratory reporting limits. However, the EPA 8020 analysis of the (MW-3)✓ groundwater sample indicated the presence of BTEX compounds ranging from 1L2 to 9.7 parts- per-billion (ppb). The 8020 a�lysis of the groundwater sample collected from✓MW-2 indicated the presence of total xylenes at 0.5 ppb. The 8020 analysis also indicated that the equipment and drip blanks eaab contained 10 ppb toluene. NET's laboratory method blank contained concentrations of toluene at Q.34 ppb- and total xylenes at 0.48 ppb. In a letter dated March 1, 1995, NET reported a consistent problem with laboratory-induced contamination of groundwater samples. The letter is included with the attached laboratory report. Next Quarter's Activity Quarterly monitoring and sampling for the site is scheduled for May 1995. 93479047.ELT .2-