ARCHIVED REPORTS_XR0006925 - Laserfiche WebLink

Home Browse Search

I w 1 26 April 2004 AGE-NC Project No 97-0333 M ' Page 5 of 12 1 I 1 1 3 0. REBOUND RESPONSE TEST - GROUND WATER In accordance with a SJCEHD verbal directive on 13 October 2003,ground water rebound response ' testing was performed at the site on 14 October 2003 from wells MW-1,MW-2,MW-3 and MW-6 to evaluate whether or not ground water`spikes' or significant increases in dissolved contamination would occur following the temporary suspension of ground water extraction and treatment remediation between 18 September and 20 October 2003 Following the shut-down of the extraction I and treatment remediation system on 18 September 2003 (26 days), ground water monitoring and sampling were performed at from wells MW-1, MW-2, MW-3 and MW-6 Prior to groundwater sampling,approximately 5 to 9%z gallons of ground water(a minimum of three casing-water volumes per well) were evacuated (purged) from wells MW-1, MW-2, MW-3 and ' MW-6 utilizing disposable polyethylene bailers Temperature,pH and conductivity were measured for stabilization,at regular purge-volume intervals from each well using an Oakton water analyzer Field data and logs are provided in Appendix D The purged ground water was transferred to the ' ground water remediation system holding tank for treatment and disposal { Ground water samples were collected from each of the above purged wells utilizing new, 2-inch diameter disposable polyethylene bailers Ground water samples were transferred into 40-m1 EPA- approved VOA vials containing 0 5 ml 18%hydrochloric acid as a sample preservative Each ground water sample was logged on a chain-of-custody form, placed in a chilled container and transported to Cal Tech Environmental Laboratories, a California DHS-certified laboratory for analysis of selected petroleum constituents 4� The analytical results detected TPH-g from wells MW-1,MW-2,MW-3 and MW-6 at concentrations as high as 50,000 gg/l (MW-6), various BTEX constituents were detected from all four wells at ' concentrations as high as 5,400 �ig/1 toluene (MW-6), MTBE was detected from all four wells at concentrations as high as 16,000 gg/l, TAME was detected from all four wells at concentrations as high as 120 gg/l(MW-2),PCE was detected from wells MW-2,MW-3 and MW-6 at concentrations +' as'high as 60 pg/1 (MW-6) No other constituents of concern were detected from the ground water rebound response test Analytical results of ground water monitoring well samples are summarized in Table 7 The laboratory reports (Cal Tech Environmental Laboratories I D No 0310-100) and ' t chain-of-custody forms are presented in Appendix E I 1 4.0. GROUND WATER MONITORING ANDISAMPLING ' On 17, 18 and r19 November 2003, ground water monitoring and sampling were performed at 47 ,groundwater monitoring wells (MW-1 through MW-13) Quarterly ground water monitoring , ' procedures for the site were outlined in,the AGE-prepared Work Plan Addendum, dated 03 April 1 I ` Advanced deoEnvironmental,Inc I