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Global Presence <br /> Personal Attention <br /> HERST & ASSOCIATES, INC.® RECEIVED <br /> OCT 2 9 2010 <br /> Mr.Rick Jaime <br /> California Department of Corrections and Rehabilitation ENVIRONMENTAL HEALTH <br /> 7650 S.Newcastle Road/P.O.Box 213004 PERMIT/SERVICES <br /> Stockton,CA 95213-9004 <br /> October 28,2010 <br /> Dear Mr.Jaime: <br /> ' Summary of Northern California Youth Correctional Center Sampling Results <br /> September 2010 <br /> ' On September 2,2010, 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 /> performed by TestAmerica,Inc. <br /> Well #4 (reported to be the primary water supply well for the facility) exhibited a tetrachloroethene <br /> concentration below the Maximum Contaminant Limit(MCL). The September 2010 tetrachloroethene <br /> concentration at Well#4 was reported at 1.9µg/1 compared to an MCL of 5 µg/1. Trichloroethene was <br /> not detected at Well#4 during the September 2010 event. <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 slightly above the MCL. The <br /> ' September 2010 tetrachloroethene concentration at Well #1 was reported at 5.1 µg/1 compared to an <br /> MCL of 5 µg/1. Trichloroethene was detected at Well #1 during this event at a concentration of 0.90 <br /> µg/l(estimated value)compared to an MCL of 5µg/1. <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 September 2010 tetrachloroethene <br /> concentration at Well#2 was reported at 7.2 µg/1 compared to an MCL of 5 µg/1. Trichloroethene was <br /> detected at 1.8µg/1 compared to an MCL of 5 µg/1. <br /> ' During the September 2010 sampling event,the indoor faucet sample location had a tetrachloroethene <br /> concentration of 1.7 µg/1 compared to an MCL of 5 µg/1, and a trichloroethene was not detected at the <br /> indoor faucet during this event. <br /> ' Quality assurance samples collected during the September 2010 sampling event included a field blank <br /> at Well #4, a field blank at the indoor faucet, a trip blank, and duplicate samples at Well #1 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 /> ' 4631 North St.Peters Parkway Telephone(636)939-9111 <br /> St.Charles, Missouri 63304 Fax(636)939-9757 <br />