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17 October 2000 <br /> *. AGE-NC Project No. 98-046$ <br /> ' Page 2 of 4 <br /> 2.2• .COLLECTION AND ANALYSIS OF GROUND WATER SAMPLES <br /> Water samples were collected from each monitoring well using new disposable bailers after allowing <br /> the well's to achieve a minimum 80% recovery of the pre-purge water volume. The samples were <br /> • transferred into 40-m1 EPA-approved vials containing 0.5 ml 18% hydrochloric acid as a sample <br /> preservative and into 1-liter amber bottles without a sample preservative. The sample vials were then <br /> ' labeled with the monitoring well designation, date, time of sampling and the sampler's initials. The <br /> samples were transported in a chilled container under chain of custody to McCambell Analytical Inc. <br /> (MAI),a California Department of Health Services(DHS) led analytical laboratory for analysis. <br /> The samples were analyzed for: <br /> 1 <br /> • Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA <br /> ' Method 8015-Modified; <br /> • Total petroleum hydrocarbons quantified as diesel (TPH-d) in accordance with EPA Method <br /> 8015 Modified, <br /> • Volatile aromatic compounds, specifically benzene,toluene, ethylbenzene, and total xylenes <br /> (BTEX) with methyl tertiary butyl.ether(MTBE)in accordance with EPA Method 8020, and <br /> 1 Oxygenated fuel additives: MTBE,tertiary butyl alcohol (TBA), di-isopropyl ether (DIPS), <br /> ethyl tertiarybutyl ether(ETBE) and tertiary.amyl methyl ether.(TAME)in accordance with <br />'. ' EPA Method 8260-Modified. <br /> Chain-of-custody protocols were used to document sample custody transfers from the field to the <br /> ' analytical laboratory. Sample chain-of-custody forms and laboratory reports are provided in <br /> Appendix B. <br /> 1 <br /> 3.0. FINDINGS <br /> Ground water elevation and flow direction were calculated from field data; hydrocarbon-impact to <br /> ground water was inferred from laboratory analysis of the ground water samples. <br /> 3.1. GROUND WATER ELEVATION AND FLOW DIRECTION <br /> During the July 2000 monitoring event, the depth to ground water at the site ranged from 9.31 to <br /> 10.01 feet below the tops of well casings (btoc) (Table 1). Ground water elevation at the site ranged <br /> from 2.42 to 2.93 feet below mean'sea level (MSL). Ground water elevation in the monitoring wells <br /> 1 Advanced GeoEnvironmental,Inc. <br />