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�.. §eofogicafTechnics Inc. Page 3 Groundwater Monitoring Report Project No. 723.2 January 19,2000 The dedicated Waterra pump was used to collect each sample. t. Extreme care was exercised while transferring the sample into 40-m1 VOA vialserved rp - with hydrochloric acid. All samples were checked for headspace bubbles, labeled, eser,ed into foam holders and placed in an ice chest cooled to 4°C for transport to the laboratory. The sampling technician while collecting all samples wore disposable gloves. La A chain of custody document, listing all samples collected and their intended analyses, accompanied the samples from field to the laboratory, thereby providing a means to track their movement and ensure their integrity. UW 1.3 Laboratory Analyses 6.0 The groundwater samples collected on December 16, 1999 were delivered to Sherwood Labs of Hilmar, California(certification#1440) for analysis of: • Benzene, Toluene, Ethyl Benzene, and Xylene (BTEX) by method EPA method 602 • Total Petroleum Hydrocarbons as Gasoline (TPH-G) by EPA method 5030/8015(M) • Fuel Oxygenates (MTBE, DIPE, ETBE, TAME& TBA) by EPA method 8260B The detection limits for the above analyses are listed in Table 2 of Appendix A while the lab analytical results are presented in Appendix B. 2.0 FINDINGS AND DISCUSSION The results of the groundwater sample analysis show the following: BTEX and TPH-G concentrations continued to increase in MW-2, MW-3 and MW-5. MW-4 showed an increase this quarter after a major decrease from the January 1999 event. MW-1, MW-6 & MW-101 showed decreases from the previous event. • MW-101 showed low levels of BTEX and TPH-G. The levels decreased significantly from the previous event. This well was installed in August 1999 through the upper, heavily contaminated zone of soil and groundwater. GTI has observed that these wells will typically test positive for contaminants due to contaminated soil and groundwater being dragged down the borehole during drilling. This drilling artifact usually dissipates within a few months of the drilling and any contamination that is present long term is a ,., portion of the larger groundwater plume. GTI recommends continued quarterly monitoring to see if the levels decrease before further deep investigation is continued. • None of the oxygenated fuel compounds were detected by EPA method 8260. However �+ the detection limits had to be raised due to the high levels of BTEX and TPH-G that were present in many of the groundwater samples.