ARCHIVED REPORTS HUMAN HEALTH SCREENING EVALUATION

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Human Health Screening Evaluation Surland Homes—Bridle Creek February 12, 2009 ' dermal, and inhalation exposures to on-site soils was estimated to be 1E-06. This level of risk is equivalent to the incremental lifetime cancer risk point of departure, and an excess cancer risk equal to or below this threshold is considered to be acceptable (Cal/EPA, 2000 and 2001). 6.1.2 Non-Cancer Health Hazards from Soils ' Future potential oral and dermal non-cancer health hazards from direct contact exposures to on- site soils were estimated, and the hazards associated with individual COPCs and the summation of hazards associated with all COPCs for these routes are provided in Table 11. Potential future ' indirect inhalation exposures to on-site soils and non-cancer health hazards were estimated, and the hazards for individual COPCs and the summation of hazards for all COPCs for the inhalation route are provided in Table 12. The aggregate non-cancer hazard for oral, dermal, and inhalation ' routes is provided in Table 13. The total potential non-cancer hazard from oral, dermal, and inhalation exposures to on-site soils was estimated to be 0.4. This level of hazard is below a hazard index of 1 and therefore indicates an acceptable non-cancer health hazard for exposures to ' on-site soils for a hypothetical future resident. The largest contributors to the non-cancer health hazard at the site are vanadium and nickel. ' 6.2 CONSTRUCTION WORKER SCENARIO The construction worker risk evaluation was performed using the exposure assumptions detailed in Table 7. Sources for these exposure parameters included the PEA Manual guidelines, EPA Region IX PRGs 1994 Users' Guide and Technical Background Document, and the San Francisco Bay RWQCB ESLs Technical Document. 6.2.1 Cancer Risks from Soils ' Future potential oral and dermal cancer risks from direct contact exposures to on-site soils were estimated, and the cancer risks associated with individual COPCs and the summation of cancer risks associated with all COPCs for these exposure routes are provided in Table 14. Potential future indirect inhalation exposures to on-site soils and cancer risks were also estimated and the risk associated with individual COPCs and the summation of inhalation risks are provided in Table 15. The aggregate risks for oral, dermal, and inhalation cancer risks are provided in Table 16. Total potential cancer risk to a construction worker from oral, dermal, and inhalation exposures to on-site soils was estimated to be 4E-08. This level of risk is below the incremental lifetime cancer risk point of departure, and is therefore considered to be acceptable (Cal/EPA, 2000 and 2001). 6.2.2 Non-cancer Health Hazards from Soils Future potential oral and dermal non-cancer health hazards from direct contact exposures to on- site soils were estimated, and the hazards associated with individual COPCs and the summation of hazards associated with all COPCs for these routes are provided in Table 17. Potential future indirect inhalation exposures to on-site soils and non-cancer health hazards were estimated, and the hazards associated with individual COPCs and the summation of hazards for all COPCs for ' the inhalation route are provided in Table 18. The aggregate non-cancer hazard for oral, dermal, and inhalation routes is provided in Table 19. The total potential non-cancer hazard from oral, dermal, and inhalation exposures to on-site soils by a construction worker was estimated to be ' 12 AMR.. From Science to Solutions