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4 May 1995 AGE-NC-95-0118 Page 3 of 4 3.2. GROUND WATER SAMPLE COLLECTION AND ANALYSIS Water samples were collected from each well using a new disposable plastic bailer. Samples were collected in 40-m1 EPA vials. The samples were logged on a chain-of-custody form, placed in a chilled container and transported to McCampbell Analytical Inc. (MAI) in Pacheco, California. Each .: -g and BTE&X in accordance with EPA methods 5030/8015m and 602, sample was analyzed for TPH respectively. The laboratory report and chain-of-custody are presented in Appendix B. i:. -' 4.0. FINDINGS 4.1. RELATIVE GROUND WATER ELEVATION AND GRADIENT The relative elevation of ground water in each well was calculated by subtracting the ground water depth from the surveyed relative casing elevation (Table 1). Between March and May 1995, ground water rose approximately 0.3 feet in each well. Between May and June 1995, ground water rose an ..,; approximately 0.1 feet. V In May 1995, the hydraulic gradient was calculated to be 0.012 ft/ft flowing S 4° W(Figure 3). In June 1995 the hydraulic gradient was calculated to be 0.010 ft/ft with a shifted flow direction of N 23° E (Figure 4). =` 4.2. ANALYTICAL RESULTS OF GROUND WATER SAMPLES TPH g was detected in water samples from MW-2 and MW-3 at concentrations of 28,000 ppb and 910 ppb, respectively. BTE&X were detected in the samples from MW-2 and MW-3 at concentrations ranging from 23 ppb (ethyl benzene, MW-3) to 5,000 ppb (toluene, MW-2). No TPH-g or BTE&X were detected in MW-1. The analytical results ares summarized in Table 2. The laboratory report and chain-of-custody are included in Appendix B. � 1 5.0. CONCLUSIONS & RECOMMENDATIONS 5.1. HYDROCARBON-IMPACTED GROUND WATER Ground water flow direction continues to shift at the site. However, overall it appears that MW-2 is now downgradient of the former UST excavation. Monthly monitoring of ground water depth and flow direction should continue through the third quarter of 1995.