ARCHIVED REPORTS HUMAN HEALTH SCREENING EVALUATION

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' Human Health Screening Evaluation Surland Homes--Bridle Creek February 12,2009 vicinity of the site. The database report dated July 1, 2008, identified five threatened or endangered species in the Union Island Quad and Tracy Quad: Swainson's hawk, California tiger salamander, valley elderberry longhorn beetle, San Joaquin kit fox, and California red-legged frog. None of these species have been observed within 1 mile of the site; the closest sighting was a Swainson's hawk approximately 1.5 miles from the site in 1981. Therefore, it does not appear that threatened, endangered, or sensitive species occur within 1 mile of the site. The database record from this CNDDB query is included as Appendix C. 9. RECOMMENDATIONS Potential on-site residential cancer risks are IE-06, equivalent to the incremental lifetime cancer risk point of departure, and an excess cancer risk equal to or below this threshold is considered acceptable. 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. As noted, groundwater contact has been eliminated as an exposure pathway, and was not evaluated in this HHSE. ' Potential on site construction worker cancer risks are 4E-08, and the non cancer health hazards are estimated at 0.1. These values both indicate that the site does not pose an unacceptable health risk to future construction workers. The results of the HHSE indicate that exposure to chemicals present in soil at the site should not result in unacceptable health risks for an adult or child on-site resident, or future construction workers. Therefore, no remedial action is necessary at the site to protect human health, and a risk management decision of no further action can be made for on-site affected soils. ' 10. REFERENCES Bradford et al 1996. Background Concentrations of trace and Major Elements in California Soil, Kearny Foundation Special Report. University of California,. March. California Department of Fish and Game, 2008. California Natural Diversity Database. July 7. Cal/EPA, 1999. Preliminary Endangerment erment Assessment Guidance Manual, Department of Toxic Substances Control. June. 1 , 2000. Letter From David L. Berry, Ph.D., Staff Toxicologist,To: Ms. Dink Mather, Site Mitigation Branch, Region 1, Re: Review of Soil and Groundwater Investigation ' Report and Human Health Screening Evaluation, Pombo Property, Tracy California. March. , 2001. Letter From David L. Berry, Ph.D., Senior Toxicologist, To: Mr. Jerry Lile, Project Manager, Site Mitigation Branch, Region 1, Re: Review of Updated Human Health Screening Evaluation, Ridgeway [former Burns] Property, Tracy California. October. 14 From Science to Solutions