US-EPA Guidelines for Exposure Assessment

Various documents have been pubhshed by the US-EPA to provide guidance for exposure assessment. 7.2.3.1 US-EPA Guidelines for Exposure Assessment 

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The US-EPA s Office of Pollution Prevention and Toxics (OPPT) uses a tiered approach to exposure assessment (US-EPA 2007a). Exposure assessments may use measured data or model estimates. Representative measured data of known quahty are preferred over model estimates and are needed to vahdate and improve models. The US-EPA Guidelines for Exposure Assessment... 

US-EPA guidelines for endpoint-specific risk assessments contain guidance on exposure issues of relevance for the particular endpoint. For example, in the US-EPA Guidelines for Reproductive Toxicity Risk Assessment (US-EPA 1996) exposure issues important to reproductive toxicity risk assessment are addressed, and a number of unique considerations regarding the exposure assessment for reproductive toxicity are discussed. 

US EPA (1992) Guidelines for exposure assessment notice. US Environmental Protection Agency. Fed Regist, 67 22888-22938. 

USEPA (1997) Guidelines for Exposure Assessment-, EPA/ 600/P-95/002Ea. Washington, DC US Environmental Protection Agency. 

The US government s new approach (2000) to health assessment of agents involves the iterative interaction of four major components basic scientific research (hazard identification), science-based toxicity/risk assessment (dose-response assessment), exposure assessment, and risk characterization (Figure 2). This section relies heavily on the US EPA guidelines for the health assessment of suspect developmental toxicants which describe how the government uses, and plans to use, developmental toxicity data as part of their weight-of-evidence approach to both the hazard identification and the dose-response assessment components of risk assessment. 

US Environmental Protection Agency (US EPA) (1992a). Guidelines for exposure assessment Notice. Fed Reg 57, 22888-22938. 

Under US EPA current guidelines for risk assessment, the acceptable exposure dose for humans (or reference dose) is 0.2 mg kg day For an average... 

A method for determining the LOD and LOQ for water samples was proposed by the US EPA. This method has also been discussed by Roy-Keith Smith in his book titled Handbook of Environmental Analysis .The method has also been proposed by the US EPA in their guidelines for Assigning Values to Non-detected/Non-quantitied Pesticide Residues in Human Health Pood Exposure Assessments . ... 

The Guidelines for Reproductive Toxicity Risk Assessment (US-EPA 1996) discuss the scientific basis for concern about exposure to agents that cause reproductive toxicity and describe the principles and procedures to be followed in conducting risk assessments for reproductive toxicity. They include the female (nonpregnant and pregnant) and male reproductive systems. 

The Guidelines for Developmental Toxicity Risk Assessment (US-EPA 1991) outline principles and methods for evaluating data from animal and human studies, exposure data, and other information to characterize risk to human development, growth, survival, and function because of exposure prior to conception, prenatally, or to infants and children. 

The most widely used of the many mathematical models proposed for extrapolation of carcinogenicity data from animal studies to low-dose human exposures (i.e., low-dose extrapolation) is the LMS model. This has, in effect, become the default approach for quantitative risk assessment and has been used by, e.g., the US-EPA for many years as well as by the WHO in relation to derivation of drinking-water guideline values for potential carcinogens (WHO 1996) (see Section 9.2.1.2 for drinking-water guideline values). 

Risk assessment is an empirically based process that estimates the risk of adverse effects from exposure of an individual or population to a chemical, physical or biological agent. The OECD test guidelines, the US EPA risk assessment guidelines and additional risk assessment procedures for new and existing chemicals have been published and put into use by many different countries in Europe, the Americas and Asia (United Kingdom Department of Health, 1991,1995 EC, 1994,1996 Health Canada, 1994 IPCS, 1994 Hertel, 1996). A list of assessments produced by various national and international agencies on specific chemicals is included in ECETOC/UNEP (1996). 

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