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GROUNDWATER MONITORING REPORT FIRST QUARTER, 1999 ` New Jerusalem School April 19, 1999 1. INTRODUCTION Condor Earth Technologies, Inc. (Condor) conducted first quarter, 1999, groundwater monitoring on March 30, ` 1999, at the New Jerusalem School located at 31400 Koster Road in Tracy, California (Figures I and 2, Appendix A). This report was prepared at the request Mr. Dennis Boyer, Superintendent of the New Jerusalem School District. The locations of the monitoring wells at the site (MW-1, MW-2, and MW-3) are shown in Figure 2, Appendix A. This report includes a site background, a description of the monitoring activities, and a summary/conclusions. .r 2. SITE BACKGROUND A Preliminary Investigation and Evaluation Report(PIER) dated February 27, 1997, was prepared by Advanced GeoEnviroamental, Inc (AGE). The fieldwork was conducted by AGE on November 18, 1996. The PIER indicated that a 1,000-gallon underground storage tank (UST) and a 350-gallon UST were removed from the site in July, 1989 and that analyses of soil samples collected from beneath the 350-gallon UST detected the presence of gasoline contamination. According to the PIER, the field investigation included the installation and sampling ;- of three soil borings and the results indicated that gasoline and gasoline constituents were present in the soil and groundwater at the site. The PIER also reported that groundwater was encountered at approximately 12 feet below the ground surface(bgs)and that the regional groundwater flow was toward the northeast. r.. Ms. Oz of the PHS/EHD subsequently directed the New Jerusalem School to submit a work plan to conduct additional investigative activities at the site including sampling and laboratory analyses of the on-site domestic well water and irrigation well water, and to conduct a groundwater receptor survey within a 2,000-foot radius of the site. At the request of Mr. Boyer and pursuant to the PHS/EHD directive, Condor prepared a work plan-Soil and Groundwater Investigation Water Well Inventory, dated October 21 and 26, 1998 describing proposed r. additional investigative activities. Ms. Oz approved the work plan with modifications by way of a faxed transmission dated November 9, 1998. Condor prepared a report titled Monitor Well Installation and Sampling, dated February 26, 1999 describing the results of the additional investigative activities performed at the site. In the report, Condor recommended that a single quarterly groundwater monitoring event be conducted at the site to confirm the analytical results of the groundwater samples collected at the site on December 29, 1998. Laboratory analyses of the groundwater samples collected from the site on December 29, 1998 failed to detect petroleum hydrocarbon constituents at or above the laboratory reported detection limits in any of the samples. 3. FIRST QUARTER, 1999,GROUNDWATER MONITORING r,. On March 30, 1999, a Condor representative was on site to measure water levels and collect groundwater samples from the site monitoring wells and the domestic and irrigation wells as part of the first quarter, 1999, quarterly groundwater monitoring event. All down-hole field equipment was decontaminated in the field with a .. solution of laboratory-grade, non-phosphate detergent and hydrocarbon-free water and rinsed with hydrocarbon- free water prior to use in the well. All field instruments were calibrated to the manufacturer's recommended standards. The water level in the wells was measured to the nearest 0.01 foot with a battery-operated, flat-tape, water-level meter. A new, disposable, polyethylene bailer was lowered into each well to collect a field- inspection sample. The bailer samples were inspected for floating product, sheen, discoloration and odor. The monitoring wells were purged with new, disposable, polyethylene bailers until three well-casing volumes of L� CONDOR i