What is reference concentration RfC?

What is reference concentration RfC?

Reference Concentration or “RfC” means an estimate of the continuous inhalation exposure to the human population, including sensitive subgroups and lifestages, that is likely to be without appreciable risk of adverse effect during a lifetime.

How do you calculate RfD value?

RfD = LOAEL/(UF x MF) = 25/8000 = 0.003 (mg/kg/day). Suppose the estimated exposure dose (EED) for humans exposed to the chemical under the proposed use pattern were 0.01 mg/kg/day (i.e., the EED is greater than the RfD).

How do you interpret cancer slope factor?

Weight-of-Evidence Classification for Carcinogens

1. A = Human carcinogen.
2. B1 = indicates that limited human data are available.
3. B2 = indicates sufficient evidence in animals and inadequate or no evidence in humans.
4. C = Possible human carcinogen.
5. D = Not classifiable as to human carcinogenicity.

What is EPA Iris?

The U.S. Environmental Protection Agency’s (EPA) Integrated Risk Information System (IRIS) Program develops human health assessments that provide health effects information on. environmental chemicals to which the public may be exposed, providing a critical part of the.

What is RfD in toxicology?

A reference dose (RfD) is defined as an estimate of a daily exposure to the human population (including sensitive subpopulations) that is likely to be without an appreciable risk of deleterious effects during a lifetime. From: Encyclopedia of Toxicology (Second Edition), 2005.

What is the minimum total uncertainty factor that EPA has used to calculate an RfD?

For calculation of RfDo, the US EPA has applied an uncertainty factor (UF) of 3 to account for the lack of data precluding reproductive toxicity as a critical effect, and to account for some uncertainty as to whether the NOAEL of the critical study accounts for all sensitive individuals.

How are reference doses determined?

Reference doses are chemical-specific, i.e. the EPA determines a unique reference dose for every substance it evaluates. Often separate acute and chronic RfDs are determined for the same substance. Reference doses are specific to dietary exposure.

What is a slope factor EPA?

The slope factor is the cancer risk (proportion affected) per unit of dose. In the IRIS chemical files the slope factor is expressed on the basis of chemical weight [milligrams of substance per kilogram body weight per day (mg/kg/day)].

What is a toxicity value?

A toxicity reference value (TRV) is a toxicological index that, when compared with exposure, is used to qualify or quantify a risk to human health.

What is unit risk factor?

(IUR) is an estimate of the increased cancer risk from inhalation exposure to a concentration of 1 µg/m3 for a lifetime. The IUR can be multiplied by an estimate of lifetime exposure (in µg/m3) to estimate the lifetime cancer risk.

What is reference reference concentration (RFC)?

Reference Concentration (RfC): An estimate (with uncertainty spanning perhaps an order of magnitude) of a continuous inhalation exposure to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime.

Where is the EPA reference dose and reference concentration Forum?

Author Risk Assessment Forum, U.S. Environmental Protection Agency, Washington, DC 20460 Subject A REVIEW OF THE REFERENCE DOSE AND REFERENCE CONCENTRATION PROCESSES Keywords EPA/630/P-02/002F, Reference Dose, Reference Concentration, Process, Risk Assessment, Review

What is EPA’s role in determining duration reference values?

As more information from additional toxicology studies, toxicokinetic studies, structure-activity relationships, and human data becomes available, EPA can have greater assurance that the appropriate species, route of exposure, and target organ system(s) are known for each duration reference value needed for a human health risk assessment.

Should RFD and RFC be used to denote duration and route of exposure?

Rather than continuing to use RfD and RfC only to denote chronic oral and inhalation reference values, respectively, standardized terminology should be developed that denotes both duration and route of exposure.