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Geologieat nchnics Inc. Page 3 1 Groundwater Monitoring Report Project No. 1030.2 • March 10, 2003 ' Before a sample was collected, the well's water level was allowed to recharge to at least 80% of its initial level. All water removed from the monitoring well and not used as a ' sample was placed in a 55 gallon DOT approved container that is properly labeled and temporarily stored on-site. ' A dedicated Waterra pump was used to collect each sample. Extreme care was exercised while collecting samples to prevent agitation of the water contained in the Waterra pump. With minimal sample aeration, water samples were transferred from the pump into 40-m1 ' VOA vials preserved with hydrochloric acid or trisodium phosphate. All samples were checked for headspace bubbles, labeled, inserted into foam holders and placed into a cooled ice chest for transport to the laboratory. ' The sampling technician wore disposable gloves while collecting all samples. 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 the movement of and ensure the integrity of the samples. ' 1.3 Groundwater Laboratory Analyses ses 1.3.1 Sherwood Labs Groundwater samples collected on November 19, 2002, were delivered to Sherwood Labs ' of Hilmar, California (certification #1400) for analyses of: • Benzene, Toluene, Ethyl Benzene, and Xylene (BTEX) by EPA method 602 Total Petroleum Hydrocarbons as Gasoline (TPH-G) by EPA method 5030/8015(M) ' • Oxygenates (7)by EPA method 8260 ❑ MTBE, ETBE, TAME, DIPE, TBA, 1,2 DCA, EDB The results of the laboratory analyses are listed in Table 3 of Appendix A. Detection limits and analytical results are presented in Appendix B. ' The analytical data were submitted to GeoTracker as required under AB 2886 on December 9, 2002. The confirmation code for the submittal is 4136417508. 2.0 FINDINGS AND DISCUSSION ' Petroleum Hydrocarbons • Trend line of the plot of petroleum hydrocarbons in MW-1 since 1997 shows that TPH- G concentrations has held steady within a wide range of concentrations. ' • MW-4 has contained low concentrations of THP-G and BTEX periodically since 1999. • MW-3 was not sampled because of root invasion. The roots will be removed and the well sampled on the next monitoring event. • Groundwater analyses of MW-101 suggest there are no gasoline range petroleum hydrocarbons impacting deep groundwater at this site. The dissolved oxygen ' concentration of 3.9 ppm substantiates this premise (Table 4).