Human and Ecological Risk Assessment - Earthjustice

Appendix GHuman Health BenchmarksFor several constituents, IRIS benchmarks for similar chemicals were used as surrogatedata. The rationale for these recommendations is as follows:• Fluoride was based on fluorine. The IRIS RfD for fluorine is based on soluble fluoride.The primary RfD cited in IRIS (6E-02 mg/kg-d) is for dental fluorosis, a cosmetic effect.In this analysis, an alternative IRIS value (1.2E-01 mg/kg-d) for skeletal fluorosis inadults was used instead.• Thallium was based on thallium chloride. IRIS contains RfDs for several thallium salts.The lowest value among the thallium salts (8E-05 mg/kg-d) is routinely used to representthallium in risk assessments.G.3 ReferencesATSDR (Agency for Toxic Substances and Disease Registry). 2009. Minimal Risk Levels(MRLs) for Hazardous Substances. Available at http://www.atsdr.cdc.gov/mrls.html.CalEPA (California Environmental Protection Agency). 1999a. Air Toxics Hot Spots ProgramRisk Assessment Guidelines: Part II. Technical Support Document for DescribingAvailable Cancer Potency Factors. Office of Environmental Health Hazard Assessment,Berkeley, CA. Available at http://www.oehha.org/air/cancer_guide/hsca2.html.CalEPA (California Environmental Protection Agency). 1999b. Air Toxics Hot Spots ProgramRisk Assessment Guidelines: Part III. Technical Support Document for the Determinationof Noncancer Chronic Reference Exposure Levels. SRP Draft. Office of EnvironmentalHealth Hazard Assessment, Berkeley, CA. Available (in two sections) athttp://www.oehha.org/air/chronic_rels/ragsii.htmlhttp://www.oehha.org/air/chronic_rels/RAGSp3draft.html.CalEPA (California Environmental Protection Agency). 2000. Air Toxics Hot Spots ProgramRisk Assessment Guidelines: Part III. Technical Support Document for the Determinationof Noncancer Chronic Reference Exposure Levels. Office of Environmental HealthHazard Assessment, Berkeley, CA. Available (in four sections) athttp://www.oehha.org/air/chronic_rels/22RELS2k.htmlhttp://www.oehha.org/air/chronic_rels/42kChREL.htmlhttp://www.oehha.org/air/chronic_rels/Jan2001ChREL.htmlhttp://www.oehha.org/air/chronic_rels/1201Crels.html.CalEPA (California Environmental Protection Agency). 2008. Air Toxics Hot Spots ProgramRisk Assessment Guidelines. Technical Support Document for the Determination ofNoncancer Chronic Reference Exposure Levels. Office of Environmental Health HazardAssessment, Berkeley, CA. Available athttp://www.oehha.org/air/hot_spots/2008/NoncancerTSD_final.pdf.U.S. EPA (Environmental Protection Agency). 1997. Health Effects Assessment Summary Tables(HEAST). EPA-540-R-97-036. FY 1997 Update. Office of Solid Waste and EmergencyResponse, Washington, DC.April 2010–Draft EPA document. G-5