National Academies Press: OpenBook

Issues in Risk Assessment (1993)

Chapter: Northern Spotted Owl

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Suggested Citation:"Northern Spotted Owl." National Research Council. 1993. Issues in Risk Assessment. Washington, DC: The National Academies Press. doi: 10.17226/2078.

Field-scale experiments could be used to validate specific risk assessment models keyed to specific pesticide-application scenarios.

Polychlorinated Biphenyls and 2,3,7,8-Tetrachlorodibenzo-p-Dioxin

This case study was an excellent example of the use of models to predict the environmental fate of persistent chemical contaminants. It included evaluations of uncertainty and descriptions of validation studies. In formal risk assessments, the models described are used to estimate spatiotemporal profiles of environmental contamination in sediment, water, and fish that are then compared with regulatory standards. Dose-response relationships are not used.

Species Introductions

Models are not currently part of the regulatory framework for USDA's species introduction program. However, the author of the case study discussed research in which models of host-parasite dynamics are being used to examine the potential effectiveness of control agents proposed for introduction. This approach was viewed by the group as being analogous to defining dose-response relationships. Some attempts are being made to use models to extrapolate from test environments to other environments of interest, but models are not used for risk characterization. No methods exist for evaluating the impact of species introductions on a regional scale.

Northern Spotted Owl

The consensus of the group was that the case study was an example of hazard identification, rather than of complete risk assessment. There was no characterization of risk or uncertainty. Models might be useful for simulating the various factors that determine spotted owl population viability. A full-scale owl population model—incorporating resource availability, habitat suitability, and competitive interaction—would allow

Suggested Citation:"Northern Spotted Owl." National Research Council. 1993. Issues in Risk Assessment. Washington, DC: The National Academies Press. doi: 10.17226/2078.
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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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