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• 31 October 2003 AGE-NC Project No 95-0173 Page 8 of 8 6.0. RECOMMENDATIONS Based upon second quarter 2003 data collected from the site, AGE recommends • Continued quarterly ground water monitoring and sampling ofwells MW-1 through MW-13, AW-lA, AW-lB, AW-2A and AW-2B, ground water sampling results will be used to monitor progress of the SVE and IAS remediation system • Continued operation of the on-site SVE and IAS remediation system, however,to optimize the effective radius of influence in the `core' area of the plume, AGE recommends only extraction from SVE wells VW-I and VW-2 and sparging pressure to wells AW-I (A and B)and AW-2(A and B) Additionally,air-flow pressure regulators should be installed at the well-heads of AW-1 (A and B) and AW-2 (A and B)which will allow independent control of air-flow to each IAS well,and allow continuous air sparging to individual wells in the IAS network Remediation progress will be re-evaluated on a quarterly basis To address deeper petroleum hydrocarbon-impacted ground water at the site, AGE previously proposed that at least one additional remediation alternative be evaluated due to the modest clean-up effectiveness being documented utilizing IAS The well-defined, laterally continuous, permeable (sandy)nature of Hydrologic Unit 2 (38 feet to 65 feet bsg)is suitable for a ground water extraction system screened solely through Hydrologic Unit 2,implementation of aground water pump-and-treat technology would augment the 1AS clean-up efforts in Hydrologic Unit 1 A revision to Work Plan Addendum (dated 06 November 2002) was approved by the SJCEHD by letter dated 18 November 2002 for installation of one ground water extraction well and performance of groundwater extraction test The groundwater extraction well was installed at the site in January 2003, well development activities were performed on the well in February 2003 During July 2003, AGE performed an 8-hour`step' and a 12-hour`constant'rate ground water pumping test to evaluate ground water extraction(i e pump-and-treat) as a remediation alternative AGE is in the process of evaluating the pump test data and a report of findings is forthcoming 7.0. LIMITATIONS Our professional services were performed using the degree of care and skill ordinarily exercised by environmental consultants practicing in this or similar localities The findings were based mainly upon analytical results provided by an independent laboratory Evaluation of the hydrogeologic conditions at the site for the purpose of this investigation is made from a limited number of available data points(e g ground water and SVE air flow samples),and subsurface conditions may vary away from these data points No other warranty, expressed or implied, is made as to the professional interpretations, opinions and recommendations contained in this report Advanced GeoEnvironmental,Inc