ARCHIVED REPORTS_XR0005710 - Laserfiche WebLink

Home Browse Search

' 04 January 2002 AGE-NC Project No 95-0173 ' Page 7 of 8 • Previous and current laboratory results of ground water samples suggest that there is a minor ' MTBE- and 1,2-DCA-impact to ground water in the areas of wells MW-2, MW-3, MW-4 and MW-5 (Tables 2 and 3) • Laboratory results of ground water samples collected from MW-13 (screened 95 to 100 feet bsg) suggest that the dissolved petroleum hydrocarbon plume extends to at least 100 feet bsg, and is at least 65 feet Cluck, however, a trend of decreasing contaminant concentrations has ' been observed from well MW-13 for six consecutive sampling events ' Based on SVE remediation data collected between 01 July 2001 and 30 September 2001, AGE concludes • The average SVE inlet vapor concentration was approximately 1,143 µg/l, the average SVE inlet flow rate was approximately 115 cubic feet per minute (Table 5) • The volume of hydrocarbons extracted by the SVE system was calculated to be approximately 170 gallons of petroleum hydrocarbons (Appendix F) during the third quarter 2001 monitoring period (Table 6) • Since initiation of the SVE system, the total volume of petroleum hydrocarbons extracted is estimated to be approximately 1,048 gallons (Table 6) ' • No general concentration trends were evident in the PID field measurements, however, a general decline from extracted soil-gas samples was apparent in analytical results over the 3" Quarter 2001 monitoring period 6.0. RECOMMENDATIONS Based upon third quarter 2001 data collected from the site, AGE recommends ' • Continued quarterly ground water monitoring and sampling of wells MW-1 through MW-13, AW-lA, AW-1B, 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, remediation progress will be reevaluated on a quarterly basis To address deeper petroleum hydrocarbon-impact, AGE proposes that ground water pump testing be performed at the site to obtain general aquifer characteristics such as hydraulic conductivity, • transmissivity, storahvity and drawdown at various pumping rates Results of the pump test would ' Advanced GeoEnvironmental,Inc 1