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C uardtno and ftawiord 17 West Fremont. 1 Page 2 700 mg/kg TPH-g. Analytical results from soil samples of MW- 1 (June 1999) in the piping area at 15 feet bsg (silty sand) were 990 milligrams per kilogram (nig/kg) 1PH-g, Ind 1 . 8 mg/kg TPH-g at 20 feet bsg (silty sand) . Hydrocarbon odor was noted by the field geologist from 5 feet bsg to 20 feet bsg of MW-1 , but not at 25 feet bsg. Soil samples from boring P3 (September 1995) located immediately south of the former dispenser and 5 feet southwest of MW-1 were 230 mg/kg TPH-g at 10 feet bsg, but dropped to 1 ;8 kg/mg at 20 feet bsg. In contrast, P7 located about 6 feet north of P3 had faint odor at 5 and 10 feet bsg with low TPH-g concentrations of 7.5 and 8.3 mg/kg, respectively, while the soil sample at 15 feet bsg (where groundwater was encountered) exhibited intense odor, although the analytical results were only 5.9 mg/kg 1PH-g. Residual soil contamination appeared to be limited to q the area around MW- 1 mid P3 from 10 feet. to 20 feet bsg, but may continue to act as a releasing source to groundwater. EHD recommends that secondary source removal, limited to the area around 1VIW-1 be considered as a part of your strategy to bring the site toward final closure. EHD directs that a corrective action plan (CAP) be submitted to this office by August 15, 2006. The CAP should include cost-effectiveness evaluation of at least two appropriate remediation alternatives for both soil and groundwater. , If you have any questions, please contactJcffrey Wong at (209) 468-0335. Donna H.eran, RENS, Director Fnvironmental Health Department C Jeffrey Wong, Senior REHS Nuel C. Henderson, Jr., PG LOP/Site Mitigation Unit 1V LOP/Site Mitigation Unit N c: RWOCB, Central Valley Region —James L. L. Barton, PG c: Advanced GeoEnvironmental, Inc. — Anna W. Behrens ti 11 J