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1 <br /> ' Global Presence <br /> Personal Attention <br /> HERST & ASSOCIATES, INC <br /> ' D <br /> ' Mr.Rick Jaime <br /> California Department of Corrections and Rehabilitation MAY 2 8 2009 <br /> 7650 S.Newcastle Road/P.O.Box 213004 <br /> Stockton,CA 95213-9004 ENVIRONMENT HEALTH <br /> PER`S"!T/S'`gVICFg <br /> May 26,2009 <br /> ' Dear Mr.Jaime: <br /> Summary of Northern California Youth Correctional Center Sampling Results <br /> tApril 2009 <br /> On April 15, 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 /> ' performed by BC Laboratories,Inc. <br /> Well #4 (reported to be the primary water supply well for the facility) yielded tetrachloroethene and <br /> ' trichloroethene concentrations well below the federal Maximum Contaminant Limits (MCLS). The <br /> April 2009 tetrachloroethene concentration at Well#4 was reported at 1.9µg/1 compared to an MCL of <br /> 5 pg/l. In April 2009, Well #4 yielded a trichloroethene concentration of 0.44 gg/l (estimated value) <br /> compared to an MCL of 5 µg/1. <br /> tWell #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 above the MCL. The April <br /> ' 2009 tetrachloroethene concentration at Well #1 was reported at 6.2 gg/l compared to an MCL of 5 <br /> gt�• <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 April 2009 tetrachloroethene concentration at <br /> Well#2 was reported at 7.0µg/1 compared to an MCL of 5 µg/1. <br /> ' The indoor faucet sample yielded a tetrachloroethene concentration of 1.6µg/1 compared to an MCL of <br /> 5 µg/1. In April 2009,the indoor faucet yielded a trichloroethene concentration of 0.26 gg/l(estimated <br /> value). <br /> Quality assurance samples collected during the April 2009 sampling event included a field blank at <br /> Well#4,a field blank at the indoor faucet,a trip blank,and duplicate samples at Well#4 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 /> ' 4630 South Highway 94—North Outer Road Telephone(636)939-9111 <br /> St.Charles,Missouri 63304 Fax(636)939-9757 <br />