Environmental Protection Agency Reference Dose

In humans the principal route of exposure to Cd is through tobacco smoke with the net result that smokers have a Cd concentration in blood 4-5 times that of non-smokers [30]. Food is the main secondary source of Cd intake as a result of Cd accumulation in agricultural soils from fertilizers and atmospheric deposition. The Environmental Protection Agency reference dose for Cd in drinking... 

United States Environmental Protection Agency, Reference Dose (RfD) Description and Use in Health Risk Assessments. Background Document 1A (March 15, 1993) internet http //www.epa.gov/iris/rfd.htm. Scientific Committee for Toxicity, Ecotoxicity and the Environment, Opinion on Phthalate migration from soft PVC toys and child-care articles - opinion expressed at the 6th CSTEE plenary meeting, Brussels, 26/27 November 1998, internet http //europa.eu.int/comm/food/fs/sc/sct/outl9 en.html. 

EL = emissions level ERA = Environmental Protection Agency HSDB = Hazardous Substances Data Bank lARC = International Agency for Research on Cancer IRIS = Integrated Risk Information System NIOSH = National Institute of Occupational Safety and Health OEL = occupational exposure limit OSHA = Occupational Safety and Health Administration PEL = permissible exposure limit RAC = reference air concentration REL = recommended exposure limit RCRA = Resource Conservation and Recovery Act RfD = reference dose TLV = threshold limit value TWA = time-weighted average WHO = World Health Organization... 

EPA. 1988d. Reference dose (RfD) Description and use in health risk assessment. Vol. I, Appendix A Integrated risk information system supportive documentation. U.S. Environmental Protection Agency, Office of Health and Environmental Assessment. EPA 600/8-86-032a. 

MRL users should also understand the MRL derivation methodology. MRLs are derived using a modified version of the risk assessment methodology the Environmental Protection Agency (EPA) provides (Barnes and Dourson 1988) to determine reference doses for lifetime exposure (RfDs). 

EPA = Environmental Protection Agency DWEL = Drinking Water Equivalent Level ODW = Office of Drinking Water RfD = reference dose USAMBRDL = United States Army Medical Bioengineering Research and Development Laboratory... 

The Environmental Protection Agency derived a reference dose (RfD) of 0.08 mg/kg/day based on the same NOAEL from the Hart (1980) study. The RfD, however, utilized an additional uncertainty factor of 10 to extrapolate to chronic exposure. 

EPA. 1989. Interim methods for development of inhalation reference doses. U.S. Environmental Protection Agency. EPA/600/8-90/066F. 

The purpose of this chapter is not to discuss the merits, or lack thereof, of using plasma cholinesterase inhibition as an adverse effect in quantitative risk assessments for chlorpyrifos or other organophosphate pesticides. A number of regulatory agencies consider the inhibition of plasma cholinesterase to be an indicator of exposure, not of toxicity. The U.S. Environmental Protection Agency, at this point, continues to use this effect as the basis for calculating the reference doses for chlorpyrifos, and it is thus used here for assessing risks. 

The Environmental Protection Agency (EPA) inhalation reference concentration (RfC) for -hexane is 0.2 mg/m3 (0.06 ppm by volume). No reference dose (RfD) has been derived for this compound (IRIS 1998). 

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