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1 10 C)'- <br /> 1 Global Presence <br /> Personal Attention <br /> HERST & ASSOCIATES, INC <br /> 1 <br /> Mr.Rick Jaime C L- ' I__ iJ <br /> 1 California Department of Corrections and Rehabilitation J <br /> 7650 S.Newcastle Road/P.O.Box 213004 OU ;, X009 <br /> Stockton,CA 95213-9004 <br /> 1 E vV1RONIVIEN i HEALI <br /> October 29,2009 PER;N-I!T'S ERUICES <br /> 1 Dear Mr.Jaime: <br /> Summary of Northern California Youth Correctional Center Sampling Results <br /> ' September 2009 <br /> On September 11, 2009,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(Table 1)included in other <br /> recent sampling events. Sampling was performed by Herst & Associates, Inc. VOC analyses were <br /> 1 performed by BC Laboratories,Inc. <br /> Well #4 (reported to be the primary water supply well for the facility) yielded a tetrachloroethene <br /> 1 concentration well below the federal Maximum Contaminant Limits (MCLS). The September 2009 <br /> tetrachloroethene concentration at Well #4 was reported at 3.6 µg/1 compared to an MCL of 5 µg/1. <br /> Trichloroethene was detected at Well#4 at a concentration of 0.62µg/1 compared to an MCL of 5 gg/I. <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 tetrachloroethane concentration below the MCL. The <br /> September 2009 tetrachloroethene concentration at Well #1 was reported at 4.7 µg/1 compared to an <br /> 1 MCL of 5 µg/1. Trichloroethene was detected at Well#1 at a concentration of 0.76µg/1 compared to an <br /> MCL of 5 µg/1. <br /> ' Well#2(now reported to be utilized only during short term emergencies, should they occur)exhibited <br /> a tetrachloroethene concentration below the MCL. The September 2009 tetrachloroethene <br /> concentration at Well#2 was reported at 3.5 gg/1 compared to an MCL of 5 µg/1. Trichloroethene was <br /> detected at 0.63 µg/1 compared to an MCL of 5 µg/1. <br /> In September 2009, the indoor faucet sample yielded a tetrachloroethene concentration of 4.6 µg/1 <br /> ' compared to an MCL of 5 µg/1, and trichloroethene was detected at a concentration of 0.71 µg/1 <br /> compared to an MCL of 5µg/1. <br /> Quality assurance samples collected during the September 2009 sampling event included a field blank <br /> 1 at Well #4, a field blank at the indoor faucet, a trip blank, and duplicate samples at Well #4 and the <br /> indoor faucet. The field blank sample at Well #4 was collected to provide an indication of VOCs <br /> present in the ambient outdoor air or the laboratory analytical process. The field blank sample at the <br /> ' indoor faucet location was collected to provide an indication of VOCs present in the ambient indoor air <br /> or the laboratory analytical process. The trip blank sample was collected to provide an indication of <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 />