Laserfiche WebLink
Table 2 <br /> Historical Groundwater Monitoring and Analytical Data <br /> 7-Eleven Store#19976 <br /> 1399 North Main Street <br /> Manteca,CA <br /> le atlor a e A Benzene omluene e ze e lee P G ` 0 0 t P ELBE„ 7 p nGt o J t a T�f <br /> v <br /> /t' m �! t , rn L tPi't feet feef <br /> Explanation <br /> TPHg=Total petroleum hydrocarbons-as-gasoline 1,2-DCA=1,2-Dichloroethane pg/L=micrograms per liter <br /> MtBE=Methyktert-butyl ether EDB=1,2-Dibromoethane mg/L=milligrams per liter <br /> TBA=Tert-butanol DTW=Depth to water —=Not sampled/not measured <br /> DIPE=Diisopropyl ether SPT=Separate-phase hydrocarbon thickness <br /> n� EtBE=Ethyl-lert-butyl ether WTE=Water table elevation <br /> TAME=Tert-amyl-methyl ether TOC=Top of casing elevation in feet above mean sea level <br /> Notes <br /> Historical data prior to 03/07/03 sample dale provided by Shaw E&I.BTEX,TPHg and MtBE analyzed using EPA Method 8020/8015 Modified. <br /> Samples analyzed using EPA Method 8260B starting with 03/11/03 sample date. <br /> PerSJCEHD letter dated July 28,2004,wells MW-4-and MW-4A are sampled annually. <br /> Per SJCEHD letter dated May 3,2005,well MW-4 is to be sampled semi-annually and MW-4A sampled quarterly. <br /> a=Deep zone well <br /> b=Laboratory results for the 11/04/99 samples collected from the nested wells MW-1 and MWAA were switched. The table shows corrected data. <br /> c=Method Blank Contamination. The method blank contains the targeted anatyte at a reportable level. <br /> d=Data Missing from Shaws Historical Table <br /> e=Matrix Spike/Matrix Spike Duplicate Results for Benzene,Toluene and MtBE were affected by the analyte concentration already present in the un-spiked sample. <br /> f=Samples from MW-5 and MW-5A inadvertently sampled from the wrong well casing on 3/11/03 and 6/27/03. The sample reported as"MW-5"was collected from MW-5A,and the sample reported as"MW-5A"was <br /> collected from MW-5. <br /> g=Hydrocarbons from TPHg do not exhibit Gasoline chromatographic pahem for sample MW-5A. <br /> h=Matrix Spike/Matrix Spike Duplicate Results for MtBE were affected by the analyte concentration already present in the un-spiked sample. <br /> i=cross-contamination of wells. Wells were Ye-sampled and monitored on May 12,2006. <br /> =Well Temporarily Inaccessible <br /> k=Tert-Butanol results may be biased slightly high. A fraction of MtBE(typically Mess than 1%)converts to Tert-Butanol during the analysis of water samples. Kiff Laboratories considers this conversion to be mathematically <br /> significant in samples that contain MtSE/Tert-Butanol in ratios of over 20:1. <br /> I=Matrix Spike/Matrix Spike Duplicate Results for Tert-Butanol were affected by the analyte concentration already present in the un-spiked sample. <br /> r � <br /> I:\7-Eleven\7-11 Stores\19976\Tables\19976 1Q12 Groundwater.xlsxHistorical Water Page 17 of 17 <br />