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Global Presence <br /> Personal Attention <br /> HERST & ASSOCIATES, INC.0 <br /> Mr.Rick Jaime <br /> California Department of Corrections and Rehabilitation <br /> 7650 S.Newcastle Road/P.O.Box 213004 <br /> Stockton,CA 95213-9004 <br /> L <br /> V -Q <br /> June 29,2010 <br /> Dear Mr.Jaime: <br /> Summary of Northern California Youth Correctional Center Sampling Results <br /> May 2010 <br /> On May 26, 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 0.89 gg/l compared to an MCL of 5 µg/l, and the trichloroethene concentration was reported at an <br /> estimated value of 0.27µg/l compared to an MCL of 5µg/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 tetrachloroethene concentration above the MCL. The May <br /> 2010 tetrachloroethene concentration at Well #1 was reported at 6.2 gg/l compared to an MCL of 5 <br /> gg/l. Trichloroethene was detected at Well#1 during this event at a concentration of 1.2 gg/l compared <br /> 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 May 2010 tetrachloroethene concentration at <br /> Well#2 was reported at 6.9 µg/l compared to an MCL of 5 µg/l. Trichloroethene was detected at 1.8 <br /> gg/l compared to an MCL of 5 ptg/l. <br /> At the indoor faucet sample location, tetrachloroethene was detected at a concentration of 5.0 gg/l <br /> compared to an MCL of 5 µg/l,and trichloroethene was reported at a value of 1.0µg/l. <br /> Herst&Associates,Inc.understands that the NCYCC experienced a coliform issue in Well#4 prior to <br /> this sampling event and as a result supplied water to the NCYC using Well #1 while it addressed the <br /> Well #4 issue. Per correspondence with Mr. Doug Mercer on June 22, 2010 and June 23, 2010, the <br /> NCYCC treated Well#4 with chlorine and switched back to Well #4 as its primary well on June 22, <br /> 2010. <br /> Quality assurance samples collected during the May 2010 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#2 and the indoor <br /> 4630 South Highway 94-North Outer Road Telephone(636)939-9111 <br /> St.Charles,Missouri 63304 Fax(636)939-9757 <br />