Laserfiche WebLink
HUMAN HEALTH SCREENING EVALUATION <br /> MOUNTAIN HOUSE DEVELOPMENT SITE #6 <br /> 1. INTRODUCTION <br /> SAIC Energy, Environment, and Infrastructure, LLC (SAIC)prepared this Human Health <br /> Screening Evaluation(HHSE) report for the Mountain House Development Site #6 (the Site) in <br /> Mountain House, San Joaquin County, California(Figure 1). SAIC performed this HHSE on <br /> behalf of Chevron Environmental Management Company (CEMC). <br /> The Central Valley Regional Water Quality Control Board(RWQCB) is the lead regulatory <br /> agency for environmental issues related to former crude-oil pipeline operations at the Site. The <br /> Site was identified in a 2001 environmental site investigation conducted by Condor Earth <br /> Technologies (Condor) along the Mountain House Development area(Condor, 2001). SAIC <br /> conducted several soil and groundwater investigations in 2008 and 2009 to delineate the extent <br /> of total petroleum hydrocarbon (TPH) impacts at the Site (SAIC, 2008 and 2010). The results of <br /> the 2009 SAIC investigation determined that the lateral and vertical extent of soil and <br /> groundwater had been delineated. The Central Valley RWQCB concurred with these findings in <br /> an August 2010 letter, and requested that a human health risk assessment be conducted for the <br /> Site (RWQCB, 2010; Appendix A). <br /> SAIC performed this HHSE to determine the potential human health cancer risks and non-cancer <br /> health hazards associated with exposure to soil residuals from historical crude-oil pipeline <br /> operations for hypothetical residential land use of the Site. Additionally, an ecological screening <br /> evaluation was conducted to assess the threat to sensitive ecological receptors. SAIC developed <br /> this HHSE using approaches and methodology consistent with those presented in the Preliminary <br /> Endangerment Assessment(PEA) Guidance Manual (California Environmental Protection <br /> Agency [Cal/EPA] Department of Toxic Substances Control [DTSC], 1999). <br /> The PEA screening evaluation methodology conforms to standard regulatory human health risk <br /> assessment guidelines promulgated by Cal/EPA and the United States Environmental Protection <br /> Agency(EPA) for the performance of health risk assessments. Evaluating potential risks to <br /> human health using the PEA Manual's HHSE procedure is consistent with CEMC's Consistent <br /> Technical Approach(CTA)prepared by Geomatrix Consultants, Inc (Geomatrix, 2005). It <br /> should be noted that the screening evaluation likely overestimates risks associated with the <br /> conditions at the Site, as the evaluation is based on conservative default assumptions. SAIC used <br /> default assumptions (i.e., a residential land-use scenario) to ensure that the evaluation was <br /> performed in a health-protective, conservative manner. If necessary and appropriate, a site- <br /> specific human health risk assessment may be performed at a later date to further refine the <br /> estimate of potential health risks. <br /> 1.1 SYNOPSIS <br /> SAIC evaluated risks from exposures to soil contaminants associated with former Old Valley <br /> Pipeline (OVP) and Tidewater Associated Oil Company(TAOC) operations at the Site. SAIC <br /> evaluated risks from exposure to constituents of potential concern(COPCs) in soil for a <br /> residential land-use scenario at the Site, and the potential for exposure of sensitive ecological <br /> receptors to COPCs. Shallow groundwater is unlikely to be used at the Site, and is minimally <br /> affected by volatile constituents associated with former OVP and TAOC operations; therefore, <br /> SAIC did not quantitatively evaluate exposures to groundwater. The results of this HHSE <br /> 1 SAI`® <br /> from SuMnoe to Solvtloas <br />