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j I <br /> 4msim 5aYums. Mc —SAAuewreN RbM Peen 1455 Saest SYwnnun. Caliendo BAGRGRGUNp <br /> 11,000 milligrams per Holman (mg/kg). Benzene was detected in only one sample at a <br /> concentration of 240 mg/lag. Petroleum hydrocarbons wets noted to increase with depth with <br /> maximum concentrations in samples colle rtdl from 25 feet big, just above groundwater. Soil <br /> samples were also cal lecter j ust above groundwater in the pilot borings for monitoring wells M W- <br /> 1 through MW-3. Norte ofthese soil samples contained petroleum hydrocarbons. <br /> Groundwater monitoring wcllsMW-1 and MW-3 were installedtonppmximately 30 f bgs,and <br /> monitoring well MW-2 was installed t0 approximately49 feetbgs. The wcllswere constructed 01' <br /> 4-inh diameter Polyvinyl chloride (PVC) screen and rating with 15 fxt of 0.010--inch sloped <br /> screen. Benzene cuncemrationsdetected in groundesnersamples wllected from moniloringwells <br /> MW-3 and MW-2 ware 2.8 micrograms per liter (pgR.) and 28,000 pfJl., respectively. <br /> (noudwater monitoring well MW-I did net contain detectible concentrations of petroleum <br /> hydrocarbons. <br /> In June and July 1989, petroleum hydrocarbon contaminatN coil in the area 0f the former <br /> unlwded gpsoline USTs was excavated and disposed owffsite. Approximately 2,000 cubic yew <br /> of contaminated soil was excavated t0 groundwater (approximately 27 In 30 feet bled. Soil <br /> samples mken fmm the muthwest portion oftlre excavation indicated theta limited volume of soil <br /> in excess offl etarget cleanup level remained but could not W removed because of site constraints. <br /> The excavation was backfilled and compacted wan imported clean soil. <br /> In August 1989, WESTGN supervised the removal 0f a 500 gallon fuel oil LIST was removed <br /> fromthen mixemportionofHSA building beneath the sidewalk along Market Street. Soil samples <br /> were collected from beneath the tank, and no petroleum hydrocarbons were detected. <br /> Groundwater monitoring well MW-I was abandoned in preparation of construction of the HSA <br /> building. The PVC casing and screen were removed and the well was ground with <br /> wmemplatu onite mixture from the bottmn using a tremie pipe. In May 1991, WPS3'GN installed <br /> five additional wells (M W-4 through MW-8) at locations up gradient and down gradient from the <br /> Site. In August 1991, lmudwaler samples were collected fmm the five new wells. Groundwater <br /> wells MW-2 and MW-3 were dry and were not sampled. 3nc five new wells captured! relatively <br /> low concentrations ofpetmleum hydrucarbnns, as compared to those previously detecod in well <br />