Risk characterization integration

Risk characterization integrates all available data. Table 4 summarizes guidance issued by the US EPA for developing chemical-specific risk characterization for reproductive effects. 

Risk characterization integrates the information derived from the effects assessment and the exposure assessment. If the exposure level is higher than the NOAEL (or LOED or the threshold), the conclusion is that there might be a health risk. 

Risk estimate Risk characterization Integrates the results of the previous steps into a risk statement that includes one or more quantitative estimates of of risk. y Risk characterization Estimating the incidence of an effect under the conditions of exposure described in the exposure assessment. 

Risk characterization is defined as the integration of the data and analysis of the above three components to determine the likelihood that humans wiU. experience any of the various forms of toxicity associated with a substance. When the exposure data are not available, hypothetical risk is characterized by the integration of hazard identification and dose—response evaluation data. 

In tlie risk characterization, conclusions about hazard and dose response are integrated witli those from the exposure assessment. In addition, confidence about tliese conclusions, including information about tlie micertainties associated with each aspect of the assessment in the final risk sununary. should be higlilighted. In tlie previous assessment steps and in tlie risk characterization, tlie risk assessor should also distinguish between variability and uncertainty. 

Risk characterization is the last step in the risk assessment procedure. It is the quantitative or semi-quantitative estimation, including uncertainties, of frequency and severity of known or potential adverse health effects in a given population based on the previous steps. Risk characterization is the step that integrates information on hazard and exposure to estimate the magnitude of a risk. Comparison of the numerical output of hazard characterization with the estimated intake will give an indication of whether the estimated intake is a health concern. ... 

In the final phase of risk analysis—risk characterization—one integrates outputs of effects and exposure assessments. Risk is expressed in qualitative or quantitative estimates by comparison with reference values (e.g., hazard quotient). The severity of potential or actual damage should be characterized with the degree of uncertainty of risk estimates. Assumptions, data uncertainties and limitations of analyses are to be described clearly and reflected in the conclusions. The final product is a report that communicates to the affected and interested parties the analysis findings (Byrd and Cothern, 2000). 

Within the framework depicted in Figure 7.1, the content of risk assessment proposed by the committee is shown as comprising four analytic steps hazard identification, dose-response assessment, human exposure assessment, and a final, integrating step called risk characterization. These four terms and the activities they describe have come to be widely accepted within the risk assessment community, on... 

The aim of the risk characterization of a chemical substance under evaluation is to integrate the hazard assessment and exposure assessment in order to evaluate the qualitative and quantitative probability for a health risk likely to occur in a given human population due to actual or predicted exposure to that specific chemical as well as the seriousness of any health risk. 

Hazard assessment and exposure assessment of chemicals are generally common stages performed similarly independent of the chemical use category (industrial chemical, pesticide, biocide, food additive, food contact material, etc.). However, variation occurs in the way in which the exposure assessment and hazard assessment information are integrated in the risk characterization step, depending on the regulation involved and the goal of the risk assessment. This wdl be addressed in more detail in the next section. 

Risk characterization (also referred to in the CTSA process as risk integration) is the integration of hazard and exposure information to quantitatively or qualitatively assess risk. 

Risk characterization A phase of the risk assessment process that integrates the exposure and stressor response profiles to evaluate the likelihood of adverse effects associated with exposure to the contaminants. 

The National Center for Environmental Assessment (NCEA), which is part of the EPA Office of Research and Development (ORD), serves as the national resource center for the overall process of human health and ecological risk assessments the integration of hazard, dose-response, and exposure data and models to produce risk characterizations. NCEA prepares a variety of documents, many of which are the source of scientific information used by EPA decision makers in developing or revising regulations. The documents can pertain to a specific medium, such as air or water, or they can be comprehensive analyses of scientific data. Many NCEA documents contain analyses... 

The final step, risk characterization, involves the integration and analysis of the existing database to provide a numerical estimate of the incidence of the adverse effect in a given population, assuming specific conditions of exposure. 

Risk characterization provides for both qualitative and quantitative descriptions of risk. The step involves integrating the results of the hazard identification, dose-response assessment, and exposure assessment to characterize risk. Often, a direct comparison between exposure criteria developed in the first two steps and the results of the exposure assessment (concentration in the environmental media or the estimated dose, as appropriate) provide a basis for determining whether risks are acceptable. Typically, if criteria are exceeded, the risk is not acceptable. What is defined as acceptable, as well as the way risk is expressed, is often a... 

Risk characterization. This compartment is comprised of the risk estimation and risk description boxes. The integration of the exposure and effects data from the analysis compartment is reconciled in the risk estimation process. 

An uncertainty assessment is an integral part of the characterization of exposure. In the majority of assessments, data will not be available for all aspects of the characterization of exposure, and those data that are available may be of questionable or unknown quality. Typically, the assessor will have to rely on a number of assumptions with varying degrees of uncertainty associated with each. These assumptions will be based on a combination of professional judgment, inferences based on analogy with similar chemicals and conditions and estimation techniques, all of which contribute to the overall uncertainty. It is important that the assessor characterize each of the various sources of uncertainty and carry them forward to the risk characterization so that they may be combined with a similar analysis conducted as part of the characterization of ecological effects. 

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