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Di Salvo Trucking Rcport August 31 1995 Page 2 approximately 15 5 feet bgs Laboratory analyses indicated 6 2 yg/kg toluene and 10 n/kg xylene ' in the sample collected from the floor of the excavation Laboratory analyses of the soil samples collected from the east sidewall indicated no evidence of hydrocarbon constituents at or above the reported laboratory detection limits No petroleum staining, odors or OVA readings were noted ' during the over-excavation Based on the results of field observations and laboratory analyses, the lateral extent of soil contamination at the site had been evaluated Groundwater was not ' encountered during the over-excavation A complete description of the over-excavation is in Over- excavation Soil Sampling Results, prepared by Condor, June 21, 1994 ' 2.3 Monitor Well Installation On June 2, 1995, Condor observed the installation of 1 monitor well (MW 1) located in the ' estimated down gradient direction approximately 10 feet northwest of the former east end of TK4 The monitor well was constructed with two-inch I D Schedule 40, flush-threaded, 0 020 machine- slotted PVC screen The screen extended from a depth of approximately 10 5 feet to 18 5 feet bgs Blank PVC casing was installed from the top of the well screen to approximately flush with the ' ground surface Laboratory analyses of the groundwater sample collected from MW 1 indicated a concentration of 0 40 mg/1 diesel A complete description of the installation, development and sampling of MW 1 is in Monitor Well Installation Report, prepared by Condor, June 28, 1995 2.4 Site Geology ' The native soil at the site from the ground surface to approximately 10 5 feet bgs consists of dark, yellowish brown to light brown, silty fine sand From 10 5 feet to approximately 16 feet, ' fine- to course, generally medium grained sand is present and from 16 feet to approximately 18 5 feet silt is present ' 3.0 WORK SCOPE Condor predicted that the removal of several pore volumes of water from MW 1 coupled with ' systematic sampling of the groundwater would effectively evaluate the lateral extent of groundwater contamination at the site Pumping a large volume of water from MW 1 was selected as a viable ' option because of the hydrogeologic conditions at the site They include • MW 1 is located down gradient and approximately 10 feet from the east end of TK4, the ' suspected source of contamination, ' 0 a silt layer was encountered during installation of MWI from 16 to at least 18 5 feet bgs, . and Nzal�i ' �� CONDOR