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' Global Presence <br /> Personal Attention <br /> HERST & ASSOCIATES, INC <br /> E <br /> ' Mr.Rick Jaime D <br /> California Department of Corrections and Rehabilitation FEB 2 S 2010 <br /> Stockton,CA 95213-9004 50 S.Newcastle P.0.Box 213004 E FF�oN�'EN T NFALTH <br /> ' ?IT/SERVICES <br /> February 24,2010 <br /> ' Dear Mr.Jaime: <br /> Summary of Northern California Youth Correctional Center Sampling Results <br /> ' January 2010 <br /> On January 20, 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) yielded tetrachloroethene and <br /> ' trichloroethene concentrations well below the federal Maximum Contaminant Limits(MCLS)of 5 µg/1. <br /> The January 2010 tetrachloroethene concentration at Well #4 was reported at 1.7 µg/1 compared to an <br /> MCL of 5 µg/1. Trichloroethene was detected at an estimated concentration of 0.41 µg/1 at Well #4 <br /> ' during this 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 above the MCL. The January <br /> ' 2010 tetrachloroethene concentration at Well #1 was reported at 5.7 µg/1 compared to an MCL of 5 <br /> µg/1. Trichloroethene was detected at Well#1 during this event at a concentration of 1.0µg/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 January 2010 tetrachloroethene concentration <br /> ' at Well#2 was reported at 6.2 µg/1 compared to an MCL of 5 µg/l. Trichloroethene was detected at 1.4 <br /> µg/1 compared to an MCL of 5 µg/1. <br /> ' In January 2010,tetrachloroethene was detected at a concentration of 1.3 µg/1 compared to an MCL of <br /> 5 µg/1,and trichloroethene was detected at an estimated concentration of 0.17 µg/1 at the indoor faucet <br /> sample location. <br /> Quality assurance samples collected during the January 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 /> 4630 South Highway 94—North Outer Road Telephone(636)939-9111 <br /> St.Charles, Missouri 63304 Fax(636)939-9757 <br />