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1 <br /> and confirmed that the extent of petroleum hydrocarbons in soil had been delineated by <br /> previous stages of the investigation. <br /> 2.5 Quarterly Monitoring Program <br /> Quarterly monitoring of groundwater at the site was initiated by GeoAudit in October 1992. <br /> Three of the five wells were monitored at that time; MW-2 and MW-3 were still dry and <br /> ' could not be sampled. Increases in the concentration of most constituents were noted in the <br /> October 1992 event. <br /> ' After installation in April of 1993, MW-6, MW-7 and MW-8 were added to the quarterly <br /> monitoring program. MW-2 and MW-3 remained dry and the gradient continued to be to <br /> the southwest. <br /> ' 2.7 Depth to Groundwater <br /> The depth to groundwater has fluctuated by several feet since 1987 due to seasonal <br /> variations. Initially, the depth was 50 feet, but fell to more than 60 feet by November 1991. <br /> Groundwater depths continued to remain depressed through 1992, but began to rise as <br /> ' precipitation returned to normal levels during the 1992-1993 rainy season. Groundwater <br /> reached a depth of 55 feet in April 1993, but fell to approximately 60 feet in October 1993. <br /> 2.8 Groundwater Gradient <br /> ' The direction of groundwater flow has changed considerably at this site. In 1987, the <br /> gradient was to the northeast, presumably due to the effects of pumping of municipal well <br /> #1, although a more eastward gradient would be predicted. Since municipal well #1 was <br /> ' abandoned, groundwater flow has returned to the regional southwesterly direction. <br /> 2.9 Remediation Well RW-1 <br /> ' In order to access the soil directly beneath the former tank, well RW-1 was installed in <br /> August 1993. This well was drilled at a 15° angle (from vertical) from a surface location <br /> ' behind the building, and completed as a 4-inch-diameter remediation well. TPH as gasoline <br /> was detected in soil samples at concentrations as great as 12,000 mg/kg (ppm) at a depth of <br /> 35 feet. BTE&X were present in soil samples at total concentrations in excess of 1,000 ppm. <br /> ' After the installation of RW-1, a Problem Assessment Report (PAR) was prepared, which <br /> included data on aquifer and vapor extraction testing (see "Problem Assessment Report: Art <br /> ' & Artists, January 1994" prepared by GeoAudit). <br /> 1 . <br /> Ce b$"l A W S—A�,I.t. 5 <br /> An A A i.QRM.9M-IA7 <br /> 1 . <br />