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Project 113-26, Page 2 004 to 009 (10einfelder). Water sample analysis in May, 1988, showed TPH-g at 140 ppb and benzene at 2.7 ppb In August, 1993, Parker Environmental Services repaired the well tops for MW-1, MW-2, and MW-3, cutting the stand tops and installing flush-mount well boxes. Locking well caps and locks were placed on each well at this time. Monitoringwell sampling was done b Parker Environmental Services in P g Y September, 1992. Free product (approxxunately one inch) was found in MW4 which is by the tanks near the store front MW-2 had a soil blockage at six feet BGS. TPH-g was present in MW-1 (220 ppb),benzene m MW-1 (2.1 ppb) and MW-3 (0.7 ppb), toluene and xylenes in both, and ethylbenzene in MW-1 only. The soil blockage was removed from MW-2 by Parker Environmental Services in December, 1992. Evidently a cup filled with dirt was lodged in the well casing. The cup was forced to the well bottom (29') and did not impair water flow to the well. Well measurements taken at the same time showed the groundwater direction flow to be toward the north A passive skimmer was installed in MW-4 by Parker Environmental Services on February 11, 1993 to collect floating product The skimmer allows gasoline to enter through a selective membrane that keeps water out. Ms Linda Turkatte, a Health Specialist from San Joaquin County, was present during the installation Groundwater samples were obtained on Febrary 17, 1993. The skimmer was removed from MW-4 and inspected. No product was evident in the collection chamber of the skimmer, and no free product was detected in the well. Groundwater elevation had risen about 0.4 feet since December, 1992, and the direction of flow had shifted from north in December to southeast. MW-2 and MW-3 were non-detect for TPH- benzene and ethylbenzene, with g► Y toluene at 3.9 ppb (parts per billion) and xylenes at about 1.7 ppb. MW-1 had TPH g at 170 ppb, and benzene, toluene, ethylbenzene, and xylene (BTEX) at 1.9, 7 2,41, and 3 2 ppb, respectively. MW4 showed the highest concentrations, with TPH-g at 45,000 ppb, and BTEX at 7,100, 2,600, 440, and 7,500 ppb. These values are slightly lower than in December, 1992 The source of the free product found in MW-4 in September, 1992, is still unknown The objective of the current work is to find the extent of the contamination, and to further characterize subsurface soil conditions and groundwater movement 20 Parker Environmental Services 4185 Rialto Court Pittsburg CA 94565-6116 ' Phone (510) 439-1024 Fax (510) 439-2566