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15 November 1995 <br /> AGE-NC Project No 95-0142 <br /> Page 2 of 19 <br /> 2 3 INITIAL SITE ASSESSMENT <br /> In September 1991, six soil bonngs were drilled at the site under the supervision of CET Petroleum <br /> hydrocarbons were detected in soil samples from five of the six soil borings Results of the <br /> investigation were summarized in a "Preliminary Investigation and Evaluation Report" dated 10 <br /> October 1991, prepared by CET <br /> 2 4 INSTALLATION OF GROUND WATER MONITORING WELLS <br /> On 9 and 10 February 1994, three ground water monitoring wells(MW-1, MW-2 and MW-3) were <br />' installed at the site by CET The wells were installed to depths of 60 feet using 20 feet of 4-inch <br /> diameter slotted PVC casing <br />' Soil samples collected during installation of the monitoring wells were analyzed for total petroleum <br /> hydrocarbons quantified as gasoline and diesel (TPH-g and TPH-d) and volatile aromatics (benzene, <br /> toluene, ethyl benzene and xylene BTE&X) TPH-g, TPH-d and BTE&X were not detected in soil <br /> samples from MW-1 or MW-2 However, TPH-g and BTE&X were detected in soil samples from <br /> MW-3 at concentrations up to 8 2 parts per million(ppm) <br />' Ground water samples were collected from wells MW-1, MW-2 and MW-3 on 22 February 1994 <br /> TPH-g was detected in MW-3 at 48,000 parts per billion (ppb) BTE&X were detected in each well <br /> at concentrations ranging from 12 ppb (toluene, MW-2) to 13,000 ppb (benzene, MW-3) <br />' Installation and sampling of the ground water monitoring wells was summanzed in the "Soil and <br /> Ground Water Investigation Report" dated 19 March 1994, prepared by CET <br />' The wells were sampled a second time on 24 October 1994 by Roger Foott Associates (RFA) TPH-g <br /> was detected in MW-3 at 12,000 ppb, BTE&X were detected in wells MW-2 and MW-3 at <br /> concentrations up to 8,800 ppb Results of the sampling were summarized in a "Quarterly <br />' Monitoring Report" prepared by RFA, dated 14 November 1994 <br />' In November 1994,RFA installed one additional monitoring well at the site (MW-4) No petroleum <br /> hydrocarbons were detected in soil samples collected during installation RFA collected ground water <br /> samples from MW4 on 6 December 1994 No TPH or BTE&X were detected in the initial sample <br />' However, because a slight odor was noted during sampling, the PHS-EHD requested that the well <br /> be re-sampled Therefore, RFA re-sampled the well on 22 December 1994 Concentrations of <br /> toluene(0 31 ppb) and xylene(0 74 ppb) in the re-sample were marginally greater than the method <br />' detection hrmts (0 3 ppb and 0 6 ppb, respectively) <br /> r <br />