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m Elft. <br /> d <br /> Groundwater-to-Indoor <br /> - Air Screening CeVel-.- <br /> ___ Constituent__ (ug/I_)-__ <br /> TPHg 586 <br /> Benzene 185 <br /> n-Butylbenzene* 2,000 <br /> sec-Butylbenzene* 3,940 <br /> 1,2-Dichloroethane <br /> Ethylbenzene 161,000 <br /> Isopropyl benzene (cumene) 522 <br /> Methyl-tertiary butyl ether(MTBE) 13,000 <br /> Naphthalene 205 <br /> n-Butylbenzene 20,900 <br /> Toluene 49,100 <br /> 1,2,4-Tnmethylbenzene 1,510 - <br /> 1,3,5-Tnmethylbenzene 1,580 <br /> Xylenes - r 16,200 r _ <br /> * Screening level is equivalent to the solubility limit' The model output indicated that the groundwater . I <br /> concentration at or above the solubility limit is not of concem for the vapor intrusion pathway <br /> Comparison of Screening Levels to Groundwater Concentrations <br /> The screening levels derived above-were compared to groundwaterYcon-centrations detected_over the <br /> past year (July 2004 to April 2005) This time penod was selected as it includes monitoring,events <br /> covering all four seasons and,represents a full year of data Because an-active remediation system is <br /> in place, using data older than the penod selected is not representative of current conditions T <br /> Table G-1 presents the screening levels for each constituent and the analytical result for each <br /> constituent in each well sampled Concentrations exceeding the screening level are highlighted As <br /> shown in the table, the majority of concentrations are below the screening level, indicating that the <br /> constituent does not pose a risk to human health via-the vapor intrusion pathway - Therefore, the <br /> remediation of these specific wells and constituents is considered complete for the vapor intrusion ' <br /> pathway and monitoring is no longer necessary T <br /> J 1Profecta10694015098-2931Worldng\ReportsldraR 2 July 2005 <br /> QMRWapor Intrusion Pathway Evaluation doc <br />