Assessing Risks to Endangered and Threatened Species from Pesticides (2013) / Chapter Skim
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Pages 3-15
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From page 3... ...
Specifically, the NRC was asked to evaluate methods for identifying the best scientific data available; to evaluate approaches for developing modeling assumptions; to identify authoritative geospatial information that might be used in risk assessments; to review approaches for characterizing sublethal, indirect, and cumulative effects; to assess the scientific information available for estimating effects of mixtures and inert ingredients; and to consider the use of uncertainty factors to account for gaps in data. The present report, which was prepared by the NRC Committee on Ecological Risk Assessment under FIFRA and ESA, is the response to that request.
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From page 4... ...
Third, FIFRA creates a national registration process in which pesticides are registered on a nationwide basis, but the ESA calls for evaluating effects on specific species and their critical habitats and thus is geographically and temporally focused. The differences between the statutes have led to conflicting approaches in evaluating risks and have contributed to the current inability to reach consensus on assessing risks to listed species from pesticides.
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From page 5... ...
Thus, the committee concludes that the risk-assessment paradigm reflected in the ecological risk assessment (ERA) process is singularly appropriate for evaluating risks posed to ecological receptors, such as listed species, by chemical stressors, such as pesticides.
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NO Formal Consultation Exposure Effects Analysis Analysis Jeopardy? REGISTRATION OR REREGISTRATION NO Risk OF PESTICIDE Characterization YES EPA DECIDES WHETHER AND UNDER WHAT CONDITIONS TO REGISTER PESTICIDE FIGURE S-1 Relationship between the Endangered Species Act (ESA)
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From page 7... ...
The ESA directs the Services to conduct assessments on the basis of the "best scientific and commercial data available." However, the ESA, its legislative history, the rules and policies of the Services, and court cases contain little guidance for elaborating the meaning of that mandate, and the agencies do not appear to have formal protocols that define "best data available." Consequently, there have been some conflicts about what data to include in the assessments. EPA and the Services do have information-quality guidelines, and each appears to use assessment factors that include data-quality and datarelevance criteria.
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From page 8... ...
Given the current practices in exposure analysis and the need to estimate pesticide exposures and the associated spatial-temporal variations experienced by listed species and their habitats, the committee envisions the following stepwise approach to exposure modeling.
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From page 9... ...
Therefore, general monitoring data cannot be used to estimate pesticide concentrations after a pesticide application or to evaluate the performance of fate and transport models. Geospatial Data, Habitat Delineation, and Exposure Analysis Habitat includes all environmental attributes present in an area that allow an organism to survive and reproduce, and habitat delineation is necessary for determining where a pesticide and a species might co-occur, for calculating spa
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From page 10... ...
The accuracy and reliability of habitat delineation and exposure analysis are increased substantially by the use of authoritative geospatial data. To be considered authoritative, geospatial data on any scale need to meet three criteria: availability from a widely recognized and respected source, public availability, and inclusion of metadata5 that are consistent with the standards of the National Spatial Data Infrastructure -- a federal interagency program to organize and share spatial data and to ensure their accuracy.
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From page 11... ...
The inability to quantify the relationship between a sublethal effect and survival or reproductive success does not mean that the sublethal effect has no influence on population persistence; but in the absence of data, the relationship remains a hypothesis that can be discussed only qualitatively with reference to the scientific literature to explain why such a hypothesis is tenable. TABLE S-1 Examples of Authoritative Sources of Geospatial Data Data Type Examples of Authoritative Data Sources Topography Topographic features can be derived from elevation data in the National Elevation Dataset, the Shuttle Radar Topography Mission, and the Global Digital Elevation Map.
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From page 12... ...
The committee concluded that population models provide a framework for incorporating baseline conditions and projected future cumulative effects into an effects analysis. One problem that arises in an effects analysis is how to extrapolate toxicity information on tested species to listed species.
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From page 13... ...
It is important to incorporate density dependence by using models with parameter values that are functions of population density or population size, but it is not accurate to assume that mortality due to pesticide exposure will be compensated for by density dependence because it is likely that such exposure will decrease the growth rate of the population at all densities and generally depress the curve of population size vs growth rate. MIXTURES: AN IMPORTANT CONCERN FOR EXPOSURE AND EFFECTS ANALYSIS Assessing the risks posed by exposure to mixtures is clearly a subject of disagreement and concern for the agencies.
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From page 14... ...
The committee, however, emphasizes that the complexity of assessing the risk posed by chemical mixtures should not paralyze the process, and it provides guidelines in Chapter 4 of its report to help in determining when and how to consider components other than a pesticide active ingredient in a risk assessment. RISK CHARACTERIZATION AND UNCERTAINTY Risk characterization is the final stage of a risk assessment in which the results of the exposure and effects analyses are integrated to provide decisionmakers with a risk estimate and its associated uncertainty.
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From page 15... ...
The committee recognizes the pragmatic demands of the pesticideregistration process and encourages EPA and the Services to consider the probabilistic methods that have already been successfully applied to pesticide risk assessments, that have otherwise appeared often in the technical literature, that are familiar to many risk-assessment practitioners, that can be implemented with commercially available software, and that are most readily explicable to decision-makers, stakeholders, and the public. The committee also recognizes that administrative and other nonscientific hurdles will need to be overcome to implement this approach, but moving the uncertainty analysis from the typical narrative addendum to an integral part of the assessment is possible and necessary to provide realistic, objective estimates of risk.
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