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r , • 31 October 1997 AGE-NC Project No 95-0137 Page 4 of 5 concentrations of TPH-g increased in a majority of the wells over the last quarter, except well MW-5 TPH-d concentrations increased in each of the wells, except well MW-2, and were highest in well MW-3 • No BTE&X compounds were detected in wells MW-4 and MW-5 Benzene and toluene concentrations decreased in wells MW-1 and MW-3 and increased in well MW-2 Ethylbenzeiie and xylene concentrations increased in wells MW-1 and MW-3 and decreased in well MW-2 All of the BTE&X concentrations fell within previous highs and lows for each compound, indicating that the observed changes aie probably natural fluctuations and to not indicate long term trends • Hydrocarbon-impacted ground water appeal s to extend northwest, north and northeast of the former RFS UST area onto the Jimco Truck Stop property The lateral extent of the TPH-d plume has not been determined east or southeast of MW-3 42 RECOMMENDATIONS Based upon ground water data collected from the site, AGE recommends the following • Additional ground water wells have been requested by the PHS-EHD north of MW-2, MW-4 and east south and north of well MW-3 to delineate the lateral extent of hydrocarbon- impacted ground water off the site A work plan has been submitted for approval by the PHS-EHD for the ,�ell installation Once the lateral extent of impacted ground water has been determined, the monitoring wells should be monitored to determine plume stability • The PHS-EHD has indicated that soil and ground water remediation is necessary at the site and that a Corrective Action Plan (CAP) should be prepared The CAP should include a minimum of three remediation feasibility studies (e g in-situ air spargmg pilot test, soil vapor extraction and select bio-enumerations) to determine appropriate remedial options for the site • The ne-.t quarterly monitoring at the site should be scheduled for January 1998 50 LIMITATIONS Our piofessional services were performed using that degree of care and skill ordinarily exercised by environrnental consultants practicing in this or similar localities The findings were based mainly • upon analytical results pion ided by an independent laboratory Evaluations of the geologic conditions at the site have been made from a limited number of available data points (i e monitoring