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1 <br /> 07 July 1997- <br /> AGE-NC <br /> 997AGE-NC Project No 95-01'21 r <br /> Page 2 of 4 <br /> 22 GROUND WATER SAMPLE COLLECTION <br />' Moni ` ri 1 <br /> to ng wells MW-1 through N ` 'V-9 were allowed to recover for a minimum of one hour prior <br />' to sample collection Water samples were collected from wells MWA through MW-9 utilizing <br /> dedicated, disposable polyethylene bailers and new nylon rope Samples were collected in one-liter <br /> amber bottles and 40-m1 EPA-approved VOA vials containing 0 5 nil 18% hydrochloric acid as a <br />' preservative Care was taken to ensure that N is,ble air bubbles wei e not present in the VOAs after <br /> filling and capping Ground water sample containers were labeled with the well designation, date, <br /> time, and the sampler's initials <br /> 2 3 LABORATORY ANALYSIS OF GROUND WATER SAMPLES <br /> Each ground water sample was logged on a chain-of-custody form, placed in a chilled container and <br /> transported to a California state-certified laboratory for analysis of total petroleum hydrocarbons <br />' quantified as gasoline and diesel (TPH-g and TPH-d), ,olatile aromatics (benzene, toluene, ethyl <br /> benzene and xylenes BTE&X) and methyl tert-butyl ether (MTBE) in accordance with appropriate <br /> EPA methods The Iaboratory report(Castle Analytical Laboratory Reference No 112 1) and chain- <br /> of-custody forms are presented in Appendix B <br /> 30. FLNDIN'GS <br /> 3 1 RELATIVE GROUND WATER ELEVATION AND GRADIENT <br /> In May 1997, the depths to ground water mw ells MW-1 through MW-9 ranged betwecn 17 25 and <br /> 19 33 feet below surface grade (bsg) Between February and May 1997, ground water elevation <br /> I decreased an average of 0 19 feet at the site <br />' During the May 1997 sampling, ground water was approximately between 4 75 and 14 4 feet above r <br /> the screened intervals in inonitonng wells W7-1 through N4W-9 <br /> In May 1997, the gradient was calculated to be 0 0013 ft/ft or approximately 7 feet per mile, directed <br /> in a northeasterly direction (Figure 3 --Surface Gi ound T47ater E-Ievatioia Contow ,�Iqp) Since <br /> December 1994 to May 1997, ground water flow direction at the site has remained relatively <br /> constant <br /> I3 2 LABORATORY RESULTS OF GROUND WATER SAMPLES <br /> TPH-g was detected in ground water samples collected from wells MW-1 through MW-4, N[W-6 and <br />