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Results Report for Subsurface Investigation and
<br /> Second Quarter 1999 Groundwater Monitoring Report
<br /> Moore Petroleum,5491 F Street,Banta,California
<br /> Page 4
<br /> =� Groundwater Samplin and Analysis
<br /> On April 22, 1999 Apex personnel collected groundwater samples from monitoring wells MW-1
<br /> and MW-3 in accordance to the Apex SOP included as Appendix A. Monitoring wells MW-1
<br /> and MW-3 are sampled on a quarterly schedule, whereas, the remaining accessible monitoring
<br /> wells are sampled on an annual basis. The samples were submitted, under chain-of-custody
<br /> documentation, to California Laboratory Services (CLS) of Ranch Cordova, California, a state-
<br /> certified analytical laboratory. The samples were analyzed for concentrations of total petroleum
<br /> hydrocarbons as gasoline (TPHg) and total petroleum hydrocarbons as diesel (TPHd) by
<br /> Modified EPA Method 8015; benzene, toluene, ethylbenzene, total xylenes (BTEX) and methyl
<br /> t-butyl ether (MTBE) by EPA Method 8020. The analytical results are summarized in Table 2.
<br /> The laboratory analytical reports and chain-of-custody form are included in Appendix C. Figure
<br /> 4-is a map showing the concentrations of TPHg, TPHd, benzene,,and MTBE in groundwater
<br /> sampled on April 22, 1999.
<br /> CONCLUSIONS
<br /> Laboratory results for quarterly groundwater sampling conducted during April 1999 showed
<br /> detectable concentrations of TPHd in monitoring well MW-1 and MW-3 and MTBE in MW-1.
<br /> Laboratory results from the subsurface investigation conducted on April 8, 1999 showed the
<br /> -s' following results for soil:
<br /> • TPHd in GP-1, GP-3, GP-5, GP-7, and GP-8;
<br /> • TPHg in GP-1, GP-3, and GP-8;
<br /> • Toluene in GP-2 and GP-3;
<br /> • Ethylbenzene in GP-1, GP-3, GP-7, and GP-8;
<br /> • Total xylenes in GP-1, GP-2, GP-3, GP-7, and GP-8; and
<br /> • MTBE in GP-5.
<br /> Laboratory results for groundwater samples collected from each Geoprobe boring are as follows:
<br /> • TPHd in GP-1, GP-3, GP-7, and GP-8;
<br /> • TPHg in GP-1, GP-3, GP-7, and GP-8;
<br /> • Benzene in GP-7;
<br /> • Toluene in GP-1, GP-3, GP-7, and GP-8;
<br /> • Ethylbenzene in GP-1, GP-3, and GP-7;
<br /> • Total xylenes in GP-1, GP-3, GP-7, and GP-8; and
<br /> • MTBE in GP-1, GP-5, GP-6, GP-7, and GP-8.
<br /> The concentrations of TPHd detected in MW-1 and MW-3 are below the Taste and Odor
<br /> Threshold of 100 ug/L. However, the level of MTBE detected in MW-1 is below the primary
<br /> drinking water standard of 13 ug/L, but slightly above the secondary value of 5 ug/L. MTBE has
<br /> SB;CAProject FilesWoore Petroleumlgp_rr.doc
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