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Report-Groundwater lhve.,. ation <br /> First Student Bus Facility(Former A.W. Hayes Facility) <br /> 2005 Navy Drive—Stockton, CA <br /> C. LABORATORY ANALYSIS OF GROUNDWATER SAMPLES <br /> The three (3) groundwater samples collected during this investigation(MW-1, MW-3 and <br /> MW-4) were transported at 4° C, under standard Chain-of-Custody procedures, to a State <br /> certified laboratory - California Laboratory Services, Inc. located at 3249 Fitzgerald Road <br /> in Rancho Cordova, California. <br /> The three (3) groundwater samples collected from the monitoring wells on May 25, 2010 <br /> were analyzed for hexane extractable material (oil and grease) by APHA/EPA Methods; <br /> total petroleum hydrocarbons as diesel (TPH-d) by EPA Method 8015M; total petroleum <br /> hydrocarbons as gasoline (TPH-g) and BTEX by GC/FID; and volatile organic <br /> compounds (VOCs) by 826013. The Laboratory Analytical Reports and Chain-of- <br /> Custody documentation for the groundwater samples are included in Appendix C. <br /> Groundwater laboratory test results are presented below in Table 4. <br /> Table 4 - Groundwater Sampling Analytical Results (May 25,2010 <br /> Sample TPH TPH HEM I,1 1,1 cis-1,2 trans-1,2- Vinyl <br /> ID Diesel Gas (Oil and Dichloro- Dichloro- Dichloro- Dichloro- Chloride <br /> Grease) ethane ethene ethene ethene <br /> MW-1 ND ND ND 0.71 ug/L 3.9 ug/L 900 u /L 110 ug/L 1.8 ug/L <br /> MW-3 ND ND ND ND ND ND ND ND <br /> MW-4 ND ND ND ND ND 11 ug/L 3.0 u /L ND <br /> ug/L—microgram/Liter(parts per billion) <br /> ND—Not detected at concentrations greater than the method detection limit(MDL) <br /> 4.0 FINDINGS AND CONCLUSIONS <br /> Laboratory test results presented in this Report indicate that volatile organic compounds <br /> (VOCs) were present in groundwater beneath the Site at the time of this investigation. <br /> VOCs detected above the California Water Goals, Maximum Contaminant Levels (MCL) <br /> for drinking water, during this investigation (May 2010) include cis-1,2-Dichloroethene <br /> in MW-1 at a concentration of 900 ug/L and in MW-4 at a concentration of 11 ug/L <br /> (MCL is 6 ug/L); and trans-1,2,-Dichloroethene in MW-1 at a concentration of 110 ug/L <br /> (MCL is 10 ug/L); and Vinyl chloride in MW-1 at a concentration of 1.8 ug/L (MCL is <br /> 1.0). <br /> VOCs detected above the MCL during the November 2008 investigation include cis- <br /> 1,2—Dichloroethene in MW-1 at a concentration of 1100 ug/L; and trans-1,2,- <br /> Dichloroethene in MW-1 at a concentration of 94 ug/L. <br /> 5 <br />