ARCHIVED REPORTS XR0011054 - Laserfiche WebLink

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LOCATION OF NEARBY WELLS,_ A major groundwater contamination problem exists in the area of the Morita site, associated with leaking UST' s at the Exxon Gaso station located diagonally across the street on the northwest corner of Charter Way and Grant Street. There are several ground water monitoring wells on that property, which have measured extremely high levels of contamination. According to personel from the EHD, the plume has not been defined, and additional work will be required. The writer does not know of any commercial or domestic water supply wells in the area, which is supplied by the City of Stockton SUMMARY OF PRIOR WORK DANE- Dec. 27L 1991 - One 5, 000 gallon leaded gasoline tank, one 5, 000 gallon & one 2,000 gallon unleaded gasoline tank, a 500 gallon waste oil tank, pump island and associated piping were removed from the site. A total of 12 soil samples were taken from • beneath the pump island, product pipeline trench, and the removed UST' s, and were analyzed for BTEX, TPH--G, EDB, & total lead. The results revealed significant amounts of BTEX & TPH--G were present in several of the samples which exceeded allowable levels. The results of that work is summarized in TABLES 1 & 2 (from ESE Inc. ) The removed spoil was returned to the excavation. Marc 25 & 26. 1992 - 7 soil borings were drilled using an auger rig to depths ranging from 36' to 56' for the purpose of deter- mining the lateral & vertical extent of the contamination Soil samples were taken at 5' intervals & screened with a PTD meter under the direction of ESE Inc personel. Selected samples were analyzed for BTEX, TPH-G, total lead & soluble lead. The results of that analysis is summarized on TABLE 3, (from ESE Inc, ) which revealed that hydrocarbon contamination had reached depths of 50' an some of the bore holes; some 15' below recent high groundwater levels measured an the area. Septi .0 & 30 1992 - Three (3) groundwater monitoring wells were placed on the property under the direction of ESE, Inc. The wells were bottomed at 65' bgl and 2 soil samples were taken from each well in the intervals 55' to 65' . The samples were analyzed for BTEX, TPA-G, & total lead; the results revealed no BTEX, and only minor amounts of TPH-G in one sample; _LTARL " However, analysis of water samples revealed significant levels of TPH-G in all three wells, Benzene in two wells, and Toluene in one well. There was no soluble lead detected in any of the samples. Refer 3