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lie 01 November 2005 AGE-NC Project No 95-0142 ' Page 3 of 8 ' • Fuel additives di-isopropyl ether(DIPS),ethyl tertiary-butyl ether(ETBE),MTBE, tertiary- amyl methyl ether(TAME)and tertiary butanol(TBA),also in accordance with EPA Method 8260B, and - ' • pH - effluent in accordance with EPA Method 150 1 ' 23 GROUND WATER MONITORING t Monitoring and sampling was performed in accordance with guidelines issued by the Central Valley Regional Water Quality Control Board (CVRWQCB) and conforms to ground water monitoring guidelines issued by the San Joaquin County Environmental Health Department(EHD) In addition, ' field work was conducted in accordance with the EHD-approved work plan Installation of Depth Discrete Wells, dated 10 December 1999 2 3 1 Well Monitoring and Purging - ' . On 24 June and l9 September 2005, a Solmst water level meter was used to measure the depth to ground water in eight monitoring wells (MW-1 through MW-8) and during the September ' monitoring selected vapor wells (VW-2 and VW-4) After ground water depth measurements, a minimum of three casing-water volumes of water were removed from monitoring wells MW-4 through MW-8 using dedicated polyethylene tubing and a Waterra inertia pump The top of the ' screened interval in wells MW-1 through MW-3 was approximately 15 feet below static water level, located beyond the point of reasonable use for determining the chemical condition of the ground water near the former UST area and therefore, these wells were not purged or sampled Temperature,pH,and electrical conductivity were measured at regular purge-volume intervals using an Oakton water analyzer Purge water stabilization field data sheets are included in Appendix B f Purged water was transferred from a Department of Transportation(DOT)-approved 55-gallon drum, , ' pumped into the on-site ground water treatment system for disposal 2 3 2 Ground Water Sample Collection ' After allowing the monitoring wells to achieve a minimum of 80%recovery of the pre-purge water volume, water samples were collected from each well using the dedicated polyethylene tubing The water was then transferred into EPA-approved 40 ml VOA vials containing 0 5 ml hydrochloric acid-(18%) as a sample preservative The vials were labeled and placed in a chilled container for • Advanced GeoEnvironmental,Inc