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' 11 August 1997 • AGE-NC Project No 95-0173 ' Page 5 of 10 ' 2 3 QUARTERLY GROUND WATER MONITORING AND SAMPLING On 17 July 1997, ground water levels and total well depths at MW-1 through MW-9 were measured I to the nearest 0 01-foot utilizing a 5olinst water level meter The relative ground water elevations were calculated by subtracting the depth to ground water from the relative casing elevations surveyed from a temporary benchmark assigned an arbitrary elevation (Table 4) Relative ground water ' elevations were plotted and contoured on a scaled site map (Figure 12 - Relative Gound Water Elevat1017Map) Ground water monitoring at this time indicated that ground water flow beneath the site was generally toward the northeast at a gradient of about 0 004, or approximately 23 feet per ' mile After water levels were measured, approximately six to nine gallons of ground water (minimum of ' three well volumes)were purged from MW-1 through MW-9 utihzing a two-stage submersible pump Temperature, pH and conductivity were measured at regular intervals using an ICM model 52200 water analyzer to track stabilization of produced water Stabilization data and field logs are included ' to Appendix E Purged ground water was stored in 55-gallon drums stored on-site in an area lacking public access ' Monitoring wells MW-1 through MW-9 were allowed to recover for a minimum of one hour prior to sample collection Ground water samples were collected utilizing a dedicated disposable ' polyethylene bailer and new nylon rope Sufficient sample was collected from each well to fill_ three 40-m1 EPA vials containing 0 5 ml 18% hydrochloric acid as a preservative, and one 1-liter amber bottle Care was taken to ensure that visible air bubbles were not present in the VOAs after filling and capping Ground -water sample containers were labeled with the well designation, date, time, and samplers initials Following collection of each ground water sample, each sample was placed in a chilled container, logged on a chain-off custody form and transported to a California state-certified Iaboratory for analysis in accordance with EPA methods 5030/8015M for TPH-g and TPH-d and for BTE&X and IMTBE in accordance with EPA method 8020 The results of the analysis are contained in Table 5 - Analytical Results Of Quay tel ly G ound Water Samples 2 3 1 STOCKPILE SOIL SAMPLES On 17 July 1997, one soil sample was collected utilizing a slide-hammer and brass sleeves from stockpiled soil at the site under the supervision of the PHS-EHD The stockpile soil sample was submitted to Castle Analytical Laboratories for laboratory analysis of TPH-g, TPH-d, BTEX and MTBE in accordance with the appropriate methods Analytical results of the soil sample are summarized in Table 1 The Iaboratory report (Castle Analytical Laboratory Reference No 113 0) and ' chain-of-custody are included in Appendix F