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Global Presence <br /> Personal Attention <br /> HERST & ASSOCIATES, INC.0 <br /> I—DI r�C( - <br /> ' Mr.Rick Jaime AUG 1 4 2008 <br /> California Department of Corrections and Rehabilitation <br /> 7650 S.Newcastle Road/P.O.Box 213004 ENVIRONNIEN T HEALTH <br /> Stockton,CA 95213-9004 PERMIT/SERVICES <br /> August 12,2008 <br /> tDear Mr.Jaime: <br /> Summary of Northern California Youth Correctional Center Sampling Results <br /> July 2008 <br /> On July 15, 2008, sampling was performed at the Northern California Youth Correctional Center <br /> (NCYCC) to provide supplemental information regarding volatile organic compound (VOC) <br /> concentrations at Well #1, Well #2, Well #4, and the indoor faucet location included in other recent <br /> sampling events. Sampling was performed by Herst&Associates,hic. VOC analyses were performed <br /> by BC Laboratories,Inc. <br /> Well #4 (reported to be the primary water supply well for the facility) yielded a tetrachloroethene <br /> concentration well below the federal Maximum Contaminant Limit (MCL). The July 2008 <br /> tetrachloroethene concentration at Well#4 was reported at 2.0 ug/l compared to an MCL of 5 ug/L. <br /> Well #1 (now reported to be a supplemental water supply well that operates about 20% of the year <br /> during peak demand periods) exhibited a tetrachloroethene concentration below the MCL. The July <br /> 2008 tetrachloroethene concentration at Well #1 was reported at 2.3 ug/1 compared to an MCL of 5 <br /> ug/l. <br /> ' Well#2 (now reported to be utilized only during short term emergencies, should they occur) exhibited <br /> a tetrachloroethene concentration above the MCL. The July 2008 tetrachloroethene concentration at <br /> ' Well#2 was reported at 9.9 ug/l compared to an MCL of 5 ug/l. <br /> The indoor faucet sample yielded a tetrachloroethene concentration of 2.0 ug/l. <br /> ' Quality assurance samples collected during the July 2008 sampling event included a field blank at Well <br /> #1, a field blank at the indoor faucet, a trip blank, and duplicate samples at Well #1 and the indoor <br /> faucet. The field blank sample at Well #2 was collected to provide an indication of VOCs present in <br /> ' the ambient outdoor air or the laboratory analytical process. The field blank sample at the indoor faucet <br /> location was collected to provide an indication of VOCs present in the ambient indoor air or the <br /> laboratory analytical process. The trip blank sample was collected to provide an indication of any <br /> ' VOCs associated with shipment or the laboratory analytical process. The duplicate samples were <br /> collected to provide an indication of sampling and laboratory testing reproducibility. <br /> ' The July 2008 field blank samples yielded no detectable concentrations of VOCs. All VOCs were <br /> reported as non-detect in the trip blank sample. Duplicate sample results for the July 2008 sampling <br /> event were similar to the original sample results,indicating good reproducibility. <br /> 1 4630 South Highway 94—North Outer Road Telephone(636)939-9111 <br /> St.Charles, Missouri 63304 Fax(636)939-9757 <br /> 1 <br />