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2.0 FLUID-LEVEL MONITORING from all monitoring wells. See Table 1 for fluid- Fluid-level monitoring is performed quarterly level monitoring data collected from October 1990 through April 1993. See Figure 3 for the ground water elevation contour map based on the April 2, 1993, fluid-level monitoring data. Refer to Appendix A for a description of fluid-level monitoring procedures. 3.0 GROUND WATER SAMPLING On April 2, 1993, ground water samples were collected from monitoring wells at the site in accordance with standard regulatory protocol (Appendix A). Ground water samples were submitted to a state-certified laboratory and analyzed for total petroleum hydrocarbons quantified as gasoline (TPH-G) using EPA Methods 5030 and 8015; total petroleum hydrocarbons as diesel (TPH-D) using EPA Methods 3510, 3520, and 8015; and benzene, toluene, ethylbenzene, and total xylenes (BTEX) using EPA Methods 5030 and 8020. The results of ground water sample analysis are listed in Table 1 and shown in Figure 4. Refer to Appendix B for a description of analytical methods, copies of the official Laboratory and Quality Assurance/Quality Control Reports, and Chain of Custody Records. 4.0 SUMMARY OF INTERIM RENIEDIATION Manual pumpouts for interim remediation of ground water began in March 1992 for AW-3, and in April 1992 for AW-9. As of April 1993, 2,410 and 3,005 gallons of ground water has been rmed periodically removed from AW-3 and , respectively. additianal 5,780 gallons pumping ground,wate�f om April 13 through April 16, 1993, evacuated an AW-9, for a total evacuated volume of 11,195 gallons. Recovered ground water was properly disposed of at Liquid Waste Management, Inc., McKittrick, California, by Balch Petroleum, Inc., Milpitas, California. Interim remediation is conducted in accordance with San Joaquin Count Public Health Services guidelines. r y 5.0 FINDINGS AND CONCLUSIONS The average depth to ground water at the site is approximately 10.4 feet below grade (fbg). The hydraulic gradient at this site is directed toward the north/northeast with a magnitude of 0.01 foot per foot. Depth to water, gradient direction, and magnitude are consistent with previous monitoring events. No free product was observed in any well at the site. No dissolved-phase TPH-G was detected at or above reported detection limits in the F onsite or offsite wells. Benzene was present in detectable concentrations icy t1 4Z rY 1 ppb) and AW-10 (0.54 ppb). BTEX concentrations were below laboratory detection limits in the remaining wells sampled. TPH-D was present in AW-3, AW-10, and AW-12 (120, 92, and 63 ppb, respectively). Ground water samples from AW-3 have 2