ARCHIVED REPORTS_XR0007212 - Laserfiche WebLink

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BACKGROUND ' The subject site was previously a gasoline service station with four (4) underground storage tanks (UST's) (1-10, 000 gallon tank containing unleaded gasoline, 1-8, 000 gallon tank containing unleaded gasoline, 1-6,000 gallon tank containing regular gasoline, ' and 1-250 gallon tank containing waste oil) . The three (3) gasoline tanks were buried in a common excavation in the central portion of the subject site and the waste oil tank was buried in a separate excavation within the building. On 10 July 1990, the four UST's were decommissioned and removed ' from the property. ETS Environmental & Associates (ETS) observed the tank removals and obtained confirmatory soil samples beneath the tanks. ' On 12 July 1990, the product lines were excavated and removed from the property. ETS observed the removal of the product lines and obtained confirmatory soil samples in the excavation. ' In October 1991, ETS submitted a Preliminary Investigation and Evaluation Report (PIER) which included soil sampling in the bottom of the open excavations, the drilling of three (3) 100' deep ' borings, and the conversion of the three borings into 2-inch diameter monitoring wells (Figure 2) . Elevated concentrations of Total Petroleum Hydrocarbons (TPH) and purgeable aromatic hydrocarbons (BTE&X) were detected in soil samples obtained from the gasoline tank excavation, the product line excavation, and in each of the three borings. The highest TPH ' concentration, 3, 300 mg/kg was detected in the soil sample obtained from boring B3 at a depth of 65.5 feet (Table 1) . Free product was also encountered in the product line excavations. 1 Elevated concentrations of Total Petroleum Hydrocarbons (TPH) and purgeable aromatic hydrocarbons (BTE&X) have been detected in ' ground water samples obtained from monitoring wells MW1, MW2 , and MW3 (Table 3) . The highest TPH concentration, 18, 000 µg/l was detected in the water sample obtained from MW1 (ETS report dated May 1992 and AC reports dated October 1992, January 1993, April 1 1993 , and June 1993) . Total petroleum hydrocarbons and BTE&X have not been detected or detected in low concentrations in the ground water samples obtained from MW2 and MW3 in the last four quarters. ' In May 1993 , Applied Consultants advanced four borings on the subject site and the conversion of three of the borings into 2"- ' diameter monitoring wells (Figure 2) . The purpose of the four borings and three monitoring wells was to further assess the limits of both the soil and ground water contamination found beneath the subject site.