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1 <br /> CGealogfcal rechmcs lnc Page 4 <br /> Groundwater Momtonng Report <br /> Project No 723 2 <br /> March 15, 2002 <br /> 1.3 Laboratory Analyses <br /> ' The groundwater samples collected on December 11, 2001, were delivered to Sherwood <br /> Labs of Hilmar, California (certification #1400) for analysis of <br /> 1 • Benzene, Toluene, Ethyl Benzene, and Xylene (BTEX),by EPA method 8020 <br /> 0 Total Petroleum Hydrocarbons as Gasoline (TPH-G) by EPA method 5030/8015(M) <br /> In addition, Sherwood Lab forwarded samples to Entech Analytical Labs, Inc of Santa <br /> Clara California (Department of Health Services Certification No 2346), for the following <br /> analysis <br /> • Oxygenated Fuel Compounds (MTBE, DIPE, ETBE, TAME & TBA) by EPA method <br /> 8260 <br /> • 1,2 DCA & EDB by EPA method 8260 <br /> ' • Methanol & Ethanol by EPA method 8015 <br /> The detection limits for the above analyses are listed in Table 2 of Appendix A, while the <br /> lab analytical results are presented in Appendix B <br /> As required under AB2886, the laboratory data was submitted electronically to GeoTracker <br /> ' on January 24, 2002 - confirmation number 2603912711 <br /> ' 2.0 FINDINGS AND DISCUSSION <br /> ' The results of the groundwater sample analysis show the following <br /> • The concentrations of BTEX and TPH-G continue to fluctuate in individual monitoring <br /> wells from one sampling event to the next However, a significant decrease in TPH-G <br /> ' concentrations was noted in MW-2 from 720,000 to 66,900 µg/l This follows a <br /> significant increase in the TPH-G concentration for the previous event <br /> • Deep well MW-201 contained a higher level of contaminant concentrations than <br /> intermediate well MW-101 This suggests that the contamination may be a drilling <br /> artifact created by the use of mud rotary drilling Additional monitoring is needed to <br /> confirm this situation <br /> • The wells did not contain MTBE, DIPE, ETBE, TAME, TBA, 1,2-DCA, EDB, or <br /> Methanol above the laboratory reporting limits Wells MW-2, MW-3 and MW-201 <br /> contain Ethanol concentrations ranging from 6 8 — I4 lig/1 We believe this is from the <br /> weighted bentonite pellets used in the annular seal of well MW-201 Additional <br /> monitoring for ethanol is not warranted as historically the compound rapidly degrades in <br /> groundwater and does not represent a threat to human health or the environment <br />