ARCHIVED REPORTS_XR0007230 - Laserfiche WebLink

Home Browse Search

Extracted air from MW-2 was monitored for the presence of volatile oiganics using a photo- ionization detector (PID) pre-calibrated to isobutylene One air sample was collected from the regenerative blower near the end of the extended purge The sample was collected in a Tedlar bag and stored in a cool ice chest The sample was then transported under chain- o€-custody to Western Environmental Science and Technology (WEST) in Davis and analyzed for total petroleum hydrocarbons (TPH as gasoline) and purgeable aromatics (BTE&X)in accordance with EPA methods 8015m and 8020 The depth-to-groundwater was also measured to surrounding wells during the groundwater extraction 3.2 Limited Vapor Extraction Test - UST Area On November 22, 1994, a limited vapor extraction test was per formed on the piping installed under the USTs located on-site A regenerative blower was connected to the piping outlet and used to extract air from the piping for approximately 90 minutes Extracted air was monitored for the presence of volatile organics using a PID One air sample was collected from the regenerative blower after approximately 15 minutes A second air sample was collected at the end of the test Air samples were analyzed for TPH as gasoline and ' BTE&X 3.3 Monitoring Well Purge Procedures On November 22, 1994, the water levels in all six wells were remeasured relative to the top of the casing A submersible pump was used to purge MW-5, a PVC bailer was used to purge MW-1, MW-3, MW-4 and MW-6 Approximately 2 to b gallons (minimum of three well volumes) of water were removed from each well Temperature, pH and conductivity were measured at one-gallon intervals Monitoring well MW-2 was purged during the extraction test Stabilization data and field logs ale included in Appendix A All purge water was stored in 55-gallon drums on-site During purging of MW-5, the removal of water caused a "bridging" of sediment to the well, making removal of the subinetsible pump difficult Theaefore, on December 12, 1994, MW-5 was redeveloped using a stainless steel bailer to jemove sediment and fines from the well 3.4 Groundwater Sample Collection and Analysis On November 22, 1994, water samples weie collected from each well using new disposable plastic bailers Two 40- ml EPA vials of water were collected fiom each well and transported I in a chilled container to WEST Laboratories Each sample was analyzed fol TPH as gasoline and BTE&X in accordance with EPA methods 8015ni and 602 respectively Laboratory reports and chains-of-custody are presented in Appendix B a.owe"I Add S.—nI— [q[I-fVrd�M'ob QI�II S