Reference Dose (RfD) 1
Reference Dose (RfD) 1 : (a) EPA toxicity value for evaluating noncarcinogenic effects resulting from exposures at Superfund sites; an estimate (with uncertainty spanning an order of magnitude or greater) of daily exposure level for humans, including sensitive subpopulations, that is likely to be without an appreciable risk or deleterious effects during a lifetime.(1) Chronic RfD: applicable for time periods of seven years to lifetime; (2) Developmental RfD: likely to be without appreciable risk of developmental effects, applicable to a single exposure event; (3) Subchronic RfD: applicable for time periods of two weeks to seven years. (Source: RAGS, 1989) [AIHA, 2000: Risk Assessment Principles for the Industrial Hygienist]; (b) An estimate delivered by the U.S. EPA (with uncertainty spanning perhaps an order of magnitude) of the daily exposure to the human population, (including sensitive subpopulations) that is likely to be without deleterious effects during a lifetime. The RfD is reported in units of mg of substance/kg body weight/day for oral exposures. [CARB, 2000: Glossary of Air Pollution Terms]; (c) An estimate of the daily ingestion dose, expressed in terms of amount per unit of body weight, that can be taken daily over a lifetime without appreciable risk. [ED, 2000: Environmental Scorecard Glossary]; (d) An estimate (with uncertainty spanning perhaps an order of magnitude) of a daily oral exposure to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime. It can be derived from a NOAEL, LOAEL, or benchmark dose, with uncertainty factors generally applied to reflect limitations of the data used. Generally used in EPA's noncancer health assessments. [IRIS, 1999: Glossary of IRIS Terms]; (e) A dose of a pesticide that the U.S. EPA considers safe for regular daily consumption by humans without adverse health effects. Generated by taking the NOAEL from animal studies and adding uncertainty factors to account for differences between animals and humans, and susceptibility within the human population. [NRDC, 1998: Trouble on the Farm]; (f) Toxicity value for evaluating noncarcinogenic (systemic) effects of daily exposure to contaminant levels without appreciable deleterious effects during a lifetime. See our toxicity values. [USDOE, 2000: RAIS Glossary]; (g) An estimate (with uncertainty spanning perhaps an order of magnitude) of a daily exposure to the human population (including sensitive subgroups) that is likely to be without appreciable risk of deleterious noncancer effects during a lifetime. [USEPA, 1995: Benchmark Dose]
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