ARCHIVED REPORTS XR0007848 - Laserfiche WebLink

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' UNDERGROUND STORAGE TANK REMOVAL ' Two 4,000-gallon USTs were removed from the southeastern portion of the site on 10 June 1997 Reportedly, the USTs had not been in operation since at least 1978 Petroleum hydrocarbons were detected in the sample collected beneath the western end of the southern UST at a concentration of ' 11,000 ppm Hydrocarbons were not detected in the three remaining samples collected beneath the USTs or one sample collected beneath "dispenser #1" The product piping was not removed or sampled during the UST removal Soil excavated during the UST removal was stockpiled at the ' southeastern corner of 121-123 E Park Street The EHD subsequently required investigation to determine the extent of impacted soil and ground water ' PREVIOUS SITE ASSESSMENTS ' Following is a brief outline of site assessment activities performed at the site to date ' Between October and November 1998,six soil probe borings were advanced at the site Total petroleum hydrocarbons quantified as gasoline (TPH-g), toluene, ethylbenzene and xylenes were detected in soil samples collected from boring B3 TPH-g was detected in grab water ' samples collected from bonngs B1, B3 and B5 Benzene, toluene, ethylbenzene and total xylenes (BTEX) were detected in the grab water sample collected from boring BI Ethylbenzene and xylenes were detected in the water sample collected from boring B3 10 On 19 October 1999, three monitoring wells (MW1, MW2 and MW3) were installed to a depth of 35 feet below surface grade(bsg) at the site TPH-g, ethylbenzene and xylenes were detected in the soil sample collected from boring MW2 at a depth of 20 feet bsg TPH-g and BTEX compounds were detected in soil samples collected from boring MW3 at depths of 20 and 25 feet bsg ' On 18 September 2001, monitoring wells MW4 and MW5 were installed at the site Petroleum hydrocarbons were not detected in any of the analyzed soil samples collected from the two pilot borings IBetween 01 and 03 October 2001, three soil probe borings were advanced at the site to collect soil and grab ground water samples to define the vertical extent of hydrocarbon- impact in the two media Petroleum hydrocarbons were not detected m the analyzed soil samples collected from the probe borings However, low concentrations of BTEX compounds and MTBE were detected in the grab ground water samples fromtwo ofthe three ' borings Based on the soil probe and monitoring well boring results, the vertical extent of impacted soil beneath the former USTs appears to be defined Also, petroleum hydrocarbons were not detected in soil samples analyzed from borings B1, B2, B4, B5, B6, MW4 and MW5, thereby defining the lateral extent of impacted soil iGround water monitoring has been performed at he site since October 1999 Ground water gradient I