three well site check bldg lch-4022

4.3.2 Dissolved-Phase HvdrocarbonsGroundwater samples were collected from monitoring welts LCH4022-2 and LCH4022-3 onMarch 29, 1993, and analyzed for the presence of dissolved-phase purgeable aromatics by EPA Method602. Groundwater samples were collected from monitoring well LCH4022-1 on June 25, 1993 and wereanalyzed for the presence of dissolved-phase purgeable aromatics by EPA Method 602. Copies of theanalytical reports including the chain-of-custody documentation are presented in Appendix B and aresummarized in Table 2. Analytical results for the groundwater samples collected indicates thatdissolved-phase petroleum hydrocarbon concentrations were detected in all of the groundwater samplescollected. Benzene and ethylbenzene concentrations in all of the groundwater samples collected aregreater than the State Water Quality Standards established by the North Carolina Department ofEnvironment, Health, and Natural Resources (NCDEHNR).Table 2Summary of Groundwater Sample Analytical ResultsBy Modified EPA Method 602March 29, 1993 and June 25, 1993Sample .Benzene TolueneLocation (PPb) (wb)LCH4022-1 12 0.9LCH4022-2 17 0.6LCH4022-3 110 C5.0DUP* 17 CO.5SWQS 1 1,000Ethylbenzene(PM446381603929XylenesW487612963400wb= parts per billion bg/L)< = less than laboratory’s reported method detection limitSWQS = state water quality standardsNOTE: DUP* is a duplicate of sample LCH4022-2.4.3.3 Liar-rid-Phase HvdrocarbonsMonitoring wells LCH4022-1, LCH4022-2 and LCH4022-3 were gauged on March 29, 1993 (Appendix D). Liquidphasehydrocarbons were not detected in monitoring wells LCH4022-2 and LCH4022-3 during the gauging event.Monitoring well LCH4022-1 contained 0.01 feet of liquid-phase hydrocarbons. On June 16, 1993, all of the wellswere gauged at the site. Monitoring wells LCH4022-2 and LCH2044-3 contained liquid-phase hydrocarbonthicknesses of 1.19 and 7.95 feet, respectively.15