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Fust Quarter 1993 Monitoring Report Coca-Cola Enterprises- West Project No 54006 03 ' Page 4 ' Results of this quarter's laboratory analyses of water samples from wells MW-1, MW-2, MW-6, and the facility well indicate the following: • Concentrations of benzene and total xylenes detected in well MW-1 Increased slightly since the last monitoring episode. The benzene concentration of 82 parts per billion (ppb) exceeded the State of California Department of Health Services Maximum ' Contaminant Level (MCL) for drinking water of 1.0 ppb. The xylene concentration of 3 2 ppb is within the MCL of 1,750 ppb The toluene concentration decreased from 0.6 ppb to nondetectable (<0 5 ppb). Ethylbenzene remained nondetectable. • In well MW-1 concentrations f P o s o TPHG Increased from 290 ppb to 500 ppb since the ' previous monitoring episode in December 1992 but are still in the same order of magnitude TPHD remained nondetectable ' • Concentrations of benzene, toluene, and xylenes detected in well MW-2 increased from nondetectable (<0 5 ppb) to 6.3 ppb, 0 7 ppb, and 1.6 ppb, respectively The benzene concentration exceeded the MCL for drinking water of 1 ppb The toluene concentration was within the State Action Limit of 100 ppb and the xylene concentration was within the MCL of 1,750 ppb. • The concentration of TPHG in well MW-2 increased from nondetectable (<50 ppb) to 130 ppb TPHD remained nondetectable. ' • Concentrations of TPHD and BTEX continue to remain nondetectable in downgradeent well MW-6 The concentration of TPHG increased from nondetectable (<50 ppb) to 120 ppb. • A comparison of depth to water and depth to bottom measured in the unrecorded facility well and this same data measured in wells MW-1 through MW-6 indicate that the facility well is completed in the shallow aquifer The well is located upgradient from the former tank pet and does not contain detectable levels of petroleum hydrocarbons, as reported in the laboratory analyses report in Appendix B. r CONCLUSIONS ' Based on the results of thisuarterl q y monitoring and previous work performed at the site, RESNA concludes that the TPHG, TPHD, and BTEX concentrations in groundwater have increased slightly since the last monitoring episode in December 1992. The majority of gasoline hydrocarbons have been consistently detected to the vicinity directly downgradeent from the ' IQMR1993 FNe,