ARCHIVED REPORTS_2007_3 - Laserfiche WebLink

Home Browse Search

' Global Presence Personal Attention HERST & ASSOCIATES, INC ' Mr.Rick Jaimie California Department of Corrections and Rehabilitation 7650 S.Newcastle Road/P.O.Box 213004 Stockton,CA 95213-9004 - July 10,2007 ' Dear Mr.Jaimie: Summary of Northern California Youth Center Sampling Results ' June 21,2007 On June 21, 2007, sampling was performed at the Northern California Youth Center (NCYC) to ' provide supplemental information regarding volatile organic compound(VOC) concentrations at Well #2, Well #4, and the indoor faucet location included in other recent sampling events. Sampling was performed by Herst&Associates,Inc. VOC analyses were performed by BC Laboratory,Inc. ' Based on the sample results,there were no MCL exceedances at the indoor faucet location during June 2007. Tetrachloroethene, which previously exceeded the MCL at the indoor faucet location, was ' reported at a concentration of 1.3 ug/l (ppb) in June compared to an MCL of 5 ug/1. A summary of detected VOCs is provided in the attached table. ' Well#2 (reported to be a supplemental water supply well that operates about 20%of the year during peak demand periods) continued to exhibit a tetrachloroethene concentration slightly above the MCL. The June 2007 tetrachloroethene concentration at Well#2 was reported at 5.9 ug/l. ' Well #4 (reported to be the primary water supply well for the facility) yielded a tetrachloroethane concentration well below the MCL. The June 2007 tetrachloroethene concentration at Well #4 was reported at 1.4 ug/l. 1 Quality assurance samples collected during the June 2007 sampling event included a field blank at Well #4,a field blank at the indoor faucet,and a trip blank. The field blank sample at Well#4 was collected ' to provide an indication of VOCs present in the ambient outdoor air or the laboratory analytical process. The field blank sample at the indoor faucet location was collected to provide an indication of VOCs present in the ambient indoor air or the laboratory analytical process. The trip blank sample was ' collected to provide an indication of any VOCs associated with shipment or the laboratory analytical process. The field blank samples yielded non-detectable concentrations of all VOCs except for tertiary- butyl alcohol that was present in both field blank samples. Tertiary-butyl alcohol was not detected in ' the samples collected from Well #2, Well #4, or the indoor faucet, suggesting that it is a laboratory- induced compound. All VOCs were reported as non-detect in the trip blank sample. Future monthly sample results will be used to verify that all VOCs in the indoor faucet remain below ' their respective MCLs. ' 4630 South Highway 94—North Outer Road Telephone(636)939-9111 St.Charles,Missouri 63304 Fax(636)939-9757