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1 <br /> ' Global Presence <br /> Personal Attention <br /> HERST & ASSOCIATES, INC <br /> o <br /> �'j l C) <br /> ' Mr.Rick Jaime RAY 2 g �� <br /> California Department of Corrections and Rehabilitation <br /> 7650 S.Newcastle Road/P.O.Box 213004 <br /> Stockton,CA 95213-9004 E��I��I�EI�a ��AI.T <br /> t PERMIT/SERVICES <br /> May 27,2010 <br /> ' Dear Mr.Jaime: <br /> Summary of Northern California Youth Correctional Center Sampling Results <br /> ' April 2010 <br /> On April 27, 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 BC Laboratories,Inc. <br /> Well #4 (reported to be the primary water supply well for the facility) had no federal Maximum <br /> ' Contaminant Limit(MCL)exceedances. The tetrachloroethene concentration at Well#4 was reported <br /> at 1.5 µg/1 compared to an MCL of 5 µg/1, and the trichloroethene concentration was reported at an <br /> estimated value of 0.36µg/1 compared to an MCL of 5 µg/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 tetrachloroethane concentration above the MCL. The April <br /> 2010 tetrachloroethene concentration at Well #1 was reported at 7.7 µg/1 compared to an MCL of 5 <br /> ' µg/1. Trichloroethene was detected at Well#1 during this event at a concentration of 1.4µg/1 compared <br /> to an 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 above the MCL. The April 2010 tetrachloroethene concentration at <br /> Well#2 was reported at 5.6 µg/1 compared to an MCL of 5 µg/1. Trichloroethene was detected at 1.2 <br /> ' µg/1 compared to an MCL of 5 µg/1. <br /> At the indoor faucet sample location, tetrachloroethene was detected at a concentration of 2.4 µg/1 <br /> ' compared to an MCL of 5 µg/1,and trichloroethene was reported at an estimated value of 0.36µg/1. <br /> Quality assurance samples collected during the April 2010 sampling event included a field blank at <br /> ' Well#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 #1 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 /> 1 <br />