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could be used for drinking water. Therefore, CRA proposes that this site be considered <br /> an exception to the default MUN designation per the Basin Plan. <br /> 2.4 RISK EXPOSURE PATHWAY ANALYSIS <br /> Possible complete exposure pathways at the site are direct exposure to impacted soil by <br /> site construction workers,ingestion of impacted groundwater,vapor intrusion from soil <br /> or groundwater, and groundwater discharge to surface water affecting aquatic <br /> receptors. These are discussed in detail below. <br /> Guidance from the San Francisco Bay Regional Water Quality Control Board <br /> (SFBRWQCB) provides environmental screening levels (ESLs)1 to assess the potential <br /> threat to these receptors. <br /> 2.4.1 SOIL <br /> Based on the investigations performed to date, some shallow (3 to 5 fbg) soil <br /> contamination remains near the loading rack and near Tank 14, and there is a potential <br /> for construction workers to come into contact with the soil. Maximum soil detections <br /> are below SFBRWQCB ESLs for direct soil contact by construction or trench workers <br /> (Table K-3 in the ESL document),with the exception of total petroleum hydrocarbons as <br /> diesel (TPHd) in a single soil sample (AS-8-5'). Construction workers are required to <br /> obtain specific permits prior to conducting work in the loading rack and bermed tank <br /> areas. Construction workers entering these areas are trained in safety practices <br /> specifically designed to avoid exposure to soil contamination. Available historical soil <br /> analytical data are presented on Table 4, and soil sampling locations are shown on <br /> Figure 2. <br /> 2.4.2 GROUNDWATER <br /> Based on the information presented in Section 2.3.4, shallow groundwater in the vicinity <br /> of the terminal is not considered an existing or potential source of drinking water. <br /> Available groundwater sampling data are presented in Table 3. <br /> 1 Screening for Environmental Concerns at Sites With Contaminated Soil and Groundwater,California <br /> Regional Water Quality Control Board,San Francisco Bay Region,Interim Final-November 2007 <br /> [Revised May 2008] <br /> 241729(33) 4 CONESTOGA-ROVERS&ASSOCIATES <br />