Exposure and risk assessment

Extensive research is currently underway to use biological markers (biomarkers) in exposure and risk assessment. Biomarkers include the reaction products of chemicals or their metabolic products with biological macromolecules, especially with DNA. They also involve indicators of effect, such as chromosomal damage, and indicators of individual genetic susceptibility. 

Assists state and local air pollution control agencies and EPA regional offices with technical matters pertaining to health, exposure, and risk assessment of air pollutants. Services are also extended to the general public, small businesses and international agencies. Thursday 8 00 a.m. to 5 00p.m., EST Friday 8 00 a.m. to 4p.m., EST. 

In 1996, the US Senate and House of Representatives passed the Food Quality Protection Act (FQPA). In order to make their exposure and risk assessments as accurate as possible, the US ERA Office of Pesticide Programs (OPP) has established guidelines to determine a value to assign for NDs. These guidelines can be summarized... 

As probabilistic exposure and risk assessment methods are developed and become more frequently used for environmental fate and effects assessment, OPP increasingly needs distributions of environmental fate values rather than single point estimates, and quantitation of error and uncertainty in measurements. Probabilistic models currently being developed by the OPP require distributions of environmental fate and effects parameters either by measurement, extrapolation or a combination of the two. The models predictions will allow regulators to base decisions on the likelihood and magnitude of exposure and effects for a range of conditions which vary both spatially and temporally, rather than in a specific environment under static conditions. This increased need for basic data on environmental fate may increase data collection and drive development of less costly and more precise analytical methods. 

A total of 10,000 iterations or calculations of dose were performed as part of this simulation, and Figure 4 shows the resulting distribution of average daily doses of chlorpyrifos as determined by the Monte Carlo simulation. Common practice in exposure and risk assessment is to characterize the 50th percentile as a "typical" exposure and the 95th percentile as the "reasonable maximum" exposure.4 The distributional analysis for these calculated doses... 

The purpose of an exposure and risk assessment is to characterize the magnitude and extent of human or environmental exposure to selected pollutants and to quantify the potential adverse effects of those exposures. The assessment can be used both to provide a baseline estimate of existing health risks attributable to an environmental pollutant and to determine the potential reduction in exposure and risk for various control options. Exposure and risk assessments are playing an increasingly central role in... 

The scope of an exposure and risk assessment may be characterized by a number of key features ... 

An exposure and risk assessment will usually integrate a number of different inputs, including health and environmental effects evaluations as well as pollutant profiles for environmental releases, ambient monitoring data, and environmental fate... 

The output of an exposure and risk assessment will usually describe the levels of exposure and quantity the population exposed for both humans and other biota, and will estimate the associated probabilities of the incidence of adverse health effects. Population exposure or risk, obtained by multiplying the individual (per capita) exposure or risk by the numbers exposed at each level of exposure, may also be a useful measure of impact. Various analyses can be performed on the results, for example, comparison of exposures in a particular geographic area against national average exposure levels. Likewise, for the same pollutant, environmental risks due to a particular industry might be compared against risks associated with occupational or household activities. In addition, the health risk of different substances could be compared for priority setting. 

Once the exposure pathways of concern have been defined, an exposure and risk assessment can be performed. 

In the following exposition, we will describe the exposure and risk assessment methods in four major steps (See Figure 1) ... 

Figure 1. Generic exposure and risk assessment methodology for environmental pollutants.

EPA. 1982f. An exposure and risk assessment for lead. Washington, DC U.S. Environmental Protection Agency, Office of Water Regulations and Standards, Monitoring and Data Support Division. EPA 440/4-85/010, NTIS PB85-220606. 

API-DSS Exposure and Risk Assessment Decision Support System Software. Estimates human exposure and risk from sites contaminated with petroleum products... 

EPA research investments since 1995 in pesticide exposure and risk assessment methods have helped pioneer novel approaches to quantify risk levels. A team at the University of Washington s School of Public Health and Community Medicine found that 2-5 year olds consuming predominantly organic foods over a 3-day period had 8.5-fold lower mean levels of OP insecticide metabolites in their urine than children eating mosdy conventional (unlabeled) foods (Curl et al., 2003). The study was carefully designed to minimize potentially... 

From a regulatory standpoint, the FDA s concern regarding safety involves the toxicity, degradants, and impurities of excipients, as discussed in other chapters in this book. In addition, other chapters of this book address types of toxicity concerns, toxicity testing strategies, and exposure and risk assessment of excipients. 

EPA, Radiation Exposure and Risks Assessment Manual (RERAM) Risk Assessment Using Radionuclide Slope Factors, EPA 402-R-96-016, U.S. Environmental Protection Agency, Washington, D.C., 1996. 

Fiksel J, Cooper C, Eschenroeder A, etal. 1981. Exposure and risk assessment for cyanide. EPA/440/4-85/008. NTIS PB85-220572. 

The bioavailability of contaminants to wildlife and humans is also an area of critical importance, where contaminants can be taken up in pore water and by dermal contact, particle ingestion, or particle inhalation. The dynamics of sorption/desorption are not currently incorporated into exposure and risk assessment models for organic compounds, where availability, in most cases, is assumed to be 100% [224]. Recently, the following have been demonstrated and reported ... 

A94023 Regulation of Municipal Sewage Sludge under the Clean Water Act Section 503 A Model for Exposure and Risk Assessment for MSW-Compost... 

EPA guidelines for exposure and risk assessment and the agency s integrated risk information system (IRIS) http //cfpub.epa.gov/ncea/... 

Golet EM, Alder AC, Giger W (2002) Environmental exposure and risk assessment of fluoroquinolone antibacterial agents in wastewater and river water of the Glatt Valley Watershed, Switzerland. Environ Sci Technol 36 3645-3651... 

This chapter provides a comprehensive examination of the current knowledge of drinking water and food contamination by PFCs and their bioaccumulation in humans, with special attention given to the fundamental role chemical analysis played in the evaluation of these compounds sources, levels, exposure and risk assessment. 

Temple WA, Ferry DG. 1988. Solvent exposures and risk assessment. In Richardson ML, ed. Risk assessment of chemicals in the environment Third European Conference, Guilford, England, UK, July 11-14, 1988. London, England Royal Society of Chemistry, 222-241. 

Nelson EDP, Shikiya D, Liu CS. 1987. Multiple air toxics exposure and risk assessment in the South Coast Air Basin. Proceedings of the APCA Annual Meeting 89 87/97.4. 

Eiuofins (2012) Toolkit dermal exposiue and risk management (RiskOfDerm Toolkit). Version A 1.11 UK-03/2004. http //www. eurofins.com/product-testing-services/ser-vices/research--development/projects-on-skin-exposure-and-protection/ riskofderm---skin-exposure-and-risk-assess-ment/download-of-riskofderm-toolkit.aspx. Accessed 28 Jan 2012... 

Simeonov, L.l. and Hassanien, M.A. (eds) (2009). Exposure and Risk Assessment of Chemical Pollution - Contemporary Methodology, Springer Science + Business Media BV. 

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