National Academies Press: OpenBook

Issues in Risk Assessment (1993)

Chapter: Risk Assessment Has Many Uses

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Suggested Citation:"Risk Assessment Has Many Uses." National Research Council. 1993. Issues in Risk Assessment. Washington, DC: The National Academies Press. doi: 10.17226/2078.

In his summary, Dr. Johnson suggested that much better communication is needed between ecologists and the public and between ecologists and economists. Ecologists need to educate the public about the importance of preservation and must learn which aspects of nature the public values most highly. Economists need help from ecologists in educating people about the interactions between natural and human systems and in understanding motives for nonuse values. Ecologists need economists to help them understand both what people care about and how intensely they care. Ecologists also need economists to communicate effectively with risk managers who face competing demands for budgetary and regulatory resources.


W. Cooper and D. W. North

Risk Assessment Has Many Uses

Because there are many uses for risk assessment, many forms of risk assessment are needed. The methodological approach and the level of detail in each form might differ a great deal, depending on the purpose for which risk assessment is carried out.

For strategic planning and setting priorities, it might be appropriate to conduct risk assessments that rely on expert judgment for direct assessments of relative risk. An example of the use of such an approach is the ecological risk portion of the recent EPA Science Advisory Report on Reducing Risk (EPA, 1990). With the direct approach, risk is assessed on the basis of overall integrated judgment to summarize each of the risks being compared. Modeling and other analytical tools are not used directly, but they can play an important role in providing the basis for expert judgment. The result of the risk assessment is a set of risk rankings that reflect the judgment of the assessors. The assessment also includes a discussion of the reasoning underlying the assessments, with explanation for differences among the experts. Because the direct approach relies on expert judgment, rather than mathematical formalism such as model calculations or statistical analysis to reach conclusions, the direct approach can be perceived as lacking in scientific rigor. However, the direct approach can be carried out quickly and might

Suggested Citation:"Risk Assessment Has Many Uses." National Research Council. 1993. Issues in Risk Assessment. Washington, DC: The National Academies Press. doi: 10.17226/2078.

provide extremely important guidance to nontechnical decision-makers, especially in the absence of any other form of integrated comparison among risks that are competing for scarce resources. In particular, such methods permit regulatory agencies to set priorities and research budgets in a proactive fashion. Such activities can counter the tendency to set priorities and research expenditures based on recent crises and public pressures—reaction to the pollutant of the month—rather than a comprehensive overview of competing risks.

Risk assessment is most often viewed as a quantitative process that is used to support specific risk management and resource management program decisions and policies. Among the biggest policy issues that involve ecological risk are acid deposition and global climate alteration. Neither of those was formally presented in the workshop, but participants in this work group frequently brought them up as examples of the most complex problems for ecological risk assessment. Application to problems of this scale is a massive undertaking. The six case studies were selected to be representative of major ecological issues of concern to government agencies. The case studies illustrate the complexities and uncertainties that the agencies must deal with on such issues. Participants observed that a complete risk assessment was not presented for any of the case studies. Yet, for each case study, a massive amount of information and analysis was described. At the local level, analytical resources are rarely available to deal with such a large amount of detail. But local communities and agency offices must deal with problems, such as remediation of hazardous waste sites, management of wildlife resources, and many other small-scale matters.

Risk assessment can provide scientific support to state or local agencies that are responsible for managing risk issues but lack the scientific and analytical resources of large federal agencies. Citizens groups might also have a strong interest in risk issues, but lack scientific capabilities and resources to carry out research and analysis. Risk assessment databases and monitoring efforts carried out by federal agencies to obtain baseline data can be useful to state, local, and citizens groups. Examples include the EPA-maintained IRIS database on toxic substances and the EMAP program the EPA is developing to obtain and make available data on ecological systems.

Risk assessment can provide guidance for identifying needed data and research. Such needs often become obvious when a risk assessment has

Suggested Citation:"Risk Assessment Has Many Uses." National Research Council. 1993. Issues in Risk Assessment. Washington, DC: The National Academies Press. doi: 10.17226/2078.
Page 331
Suggested Citation:"Risk Assessment Has Many Uses." National Research Council. 1993. Issues in Risk Assessment. Washington, DC: The National Academies Press. doi: 10.17226/2078.
Page 332
Next: Different Risk Assessment Methods Are Suited to Different Risk Assessment Needs »
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The scientific basis, inference assumptions, regulatory uses, and research needs in risk assessment are considered in this two-part volume.

The first part, Use of Maximum Tolerated Dose in Animal Bioassays for Carcinogenicity, focuses on whether the maximum tolerated dose should continue to be used in carcinogenesis bioassays. The committee considers several options for modifying current bioassay procedures.

The second part, Two-Stage Models of Carcinogenesis, stems from efforts to identify improved means of cancer risk assessment that have resulted in the development of a mathematical dose-response model based on a paradigm for the biologic phenomena thought to be associated with carcinogenesis.

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