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t Global Presence <br /> Personal Attention <br /> HERST & ASSOCIATES, INC® WbEWED <br /> /;:h <br /> 1 <br /> AUG 2 9 2009 <br /> ' Mr.Rick Jaime <br /> California Department of Corrections and Rehabilitation ENVIRONMENT HEALTH <br /> 7650 S.Newcastle Road/P.O.Box 213004 PERMIT/SERVICES <br /> ' Stockton,CA 95213-9004 <br /> August 26,2009 <br /> ' Dear Mr.Janne: <br /> Summary of Northern California Youth Correctional Center Sampling Results <br /> ' July 2009 <br /> On July 28, 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, hic. VOC analyses were <br /> ' performed by BC Laboratories,hic. <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 Limits (MCLS). The July 2009 <br /> t tetrachloroethene concentration at Well #4 was reported at 2.3 µg/1 compared to an MCL of 5 µg/1. <br /> Trichloroethene has not been detected at Well#4 for the past three(3)consecutive events. <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 /> 2009 tetmchloroethene concentration at Well #1 was reported at 3.8 µg/1 compared to an MCL of 5 <br /> µg/1. Trichloroethene was detected at 0.57µg/1 compared to an MCL of 5 gg/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 2009 tetrachloroethene concentration at <br /> Well #2 was reported at 7.4 µg/1 compared to an MCL of 5 µg/l. Trichloroethene was detected at 1.6 <br /> µg/1 compared to an MCL of 5 µg/1. <br /> ' In July 2009,the indoor faucet sample yielded a tetrachloroethene concentration of 1.7 µg/1 compared <br /> to an MCL of 5 µg/1,and trichloroethene was not detected at the indoor faucet for the third consecutive <br /> t event. <br /> Quality assurance samples collected during the July 2009 sampling event included a field blank at Well <br /> #4, a field blank at the indoor faucet, a trip blank, and duplicate samples at Well #2 and the indoor <br /> ' faucet. The field blank sample at Well #4 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 /> t4630 South Highway 94—North Outer Road Telephone(636)939-9111 <br /> St.Charles,Missouri 63304 Fax(636)939-9757 <br />