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rE/NFELDER <br /> WIMWWtlov. <br /> human health or the environment are occurring; this simply indicates that a potential for adverse <br /> risk may exist and that additional evaluation is or"may be" warranted (RWQCB, 2008). <br /> Specifically Kleinfelder compared ESLs used for exposure to humans for residential and <br /> commercial/industrial land use including groundwater protection. Kleinfelder also compared <br /> analytical data for direct exposure for commercial/industrial and construction/trench work <br /> scenarios. The referenced RWQCB sources were Tables A-1, A-2, K-2 and K-3. (Appendix G) <br /> The analytical results and the noted ESLs are located on attached Table 1. <br /> Kleinfelder included the residential scenario as it is the most conservative of those noted while <br /> the most applicable appears to be the direct exposure limits for a construction/trench worker <br /> scenario. The maximum TPHmo concentrations detected at 78 mg/kg are below the residential <br /> and commercial/industrial ceiling values ("Addresses odor, nuisance, and general ceiling limits <br /> for drinking water sources" [RWQCB, 2013]) of 100 and 500 mg/kg, respectively. The <br /> maximum TPHmo concentration detected is also well below the direct soil exposure (when <br /> considering human health) for a construction/trench and commercial/industrial worker <br /> scenario's which are 28,000 and 100,000 mg/kg, respectively. <br /> PCE was detected in one of the nine soil samples at 49 log/kg which is also below the noted <br /> ESLs which range from 550 to 31,000 µg/kg. The most conservative limit (550 µg/kg) <br /> discussed is for a residential scenario, while the most applicable for direct exposure appears to <br /> be for human health related to a construction/trench worker which is 31,000 Etg/kg. The ESL for <br /> PCE given commercial/industrial land use, when considering both human health and <br /> groundwater protection, is 700 µg/kg. The ESL for PCE for direct exposure considering a <br /> commercial/industrial worker is 2,600 µg/kg. <br /> 133385.4!/STO13R0698 Page 9 of 12 January 7,2014 <br /> Copyright 2014 Kleinfelder <br />