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D F Naugle

Publications and source records attributed to D F Naugle.

4 recordsLinked to original sources
PubMed1991

A framework for risk characterization of environmental pollutants.

Risk characterization is defined by both the U.S. National Academy of Sciences and the U.S. EPA as the estimation of human health risk due to harmful (i.e., toxic or carcinogenic) substances or organisms. Risk characterization studies are accomplished by integrating quantitative exposure estimates and dose-response relationships with the qualitative results of hazard identification. A Risk Characterization Framework has been developed to encourage a systematic approach for analysis and presentation of risk estimates. This methodology subdivides the four common components of the risk assessment process into ten elements. Each of these elements is based on a term in a predictive risk equation. The equation allows independent computations of exposure, dose, lifetime individual risk, and risk to affected populations. All key assumptions in the predictive risk equation can be explicitly shown. This is important to understand the basis and inherent uncertainties of the risk estimation process. The systematic treatment of each of the ten elements in this framework aids in the difficult job of comparing risk estimates by different researchers using different methodologies. The Risk Characterization Framework has been applied to various indoor and outdoor air pollutants of a carcinogenic nature. With further development, it also promises to be applicable to noncarcinogenic effects.

Air Pollution, Indoor↗
PubMed1991

Risk characterization framework for noncancer end points.

The nature of both indoor air exposures and noncancer end points present significant issues for risk characterization. Noncancer end points are multidimensional, affecting various organs, and are assumed to have thresholds. Symptoms also vary in severity within a population. In addition to the complexity of noncancer risk assessment, indoor air exposures are typified by the presence of complex mixtures, which further complicates the complex nature of noncancer risk characterization. Most noncancer risk assessment efforts have focused on defining acceptable daily intakes or reference doses (RfD) rather than estimating incidence and severity of the wide range of effects within an exposed population. The risk characterization framework has been developed to accommodate the RfD approach but, more importantly, to address the multidimensional nature of noncancer risk characterization. Newly emerging methods and standard EPA risk assessment guidelines for noncancer effects and complex mixtures were used as guides for developing the framework. Information and data needs have been identified from the framework. Peak, average, and cumulative doses from indoor air exposures are highly dependent on variable indoor air concentrations and affected by time-activity patterns. Susceptibility also plays a significant role in noncancer end points and, unlike susceptibility in cancer risk assessment, is quantifiable. This paper highlights the risk characterization framework for noncancer health risks that we developed in cooperation with the U.S. Environmental Protection Agency Environmental Criteria and Assessment Office. Additionally, a preliminary application of the framework to a complex mixture of volatile organic compounds from indoor sources is illustrated.

Air Pollution, Indoor↗