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Recommendations for the development and application of wildlife toxicity reference values.
Patrick Allard1, Anne Fairbrother, Bruce K Hope
1Azimuth Consulting Group, 218-2902 West Broadway, Vancouver, British Columbia, Canada.
Integrated Environmental Assessment and Management
|June 30, 2009
Summary
Toxicity reference values (TRVs) require improved methods for wildlife risk assessment. Current practices, like using NOAELs/LOAELs, are scientifically unsupported, necessitating a shift to effective dose (EDx) values for more reliable environmental hazard predictions.
Area of Science:
- Environmental toxicology
- Wildlife risk assessment
- Ecotoxicology
Background:
- Toxicity reference values (TRVs) are crucial for assessing environmental contaminant impacts on wildlife.
- Current TRV derivation and application methods lead to inconsistent hazard and risk assessments, challenging regulators and site managers.
Purpose of the Study:
- To identify and critique common, scientifically unsupported practices in TRV derivation and application.
- To recommend improved methodologies for TRV derivation that enhance the accuracy of wildlife risk assessments.
Main Methods:
- Critique of current TRV practices including hazard quotients, NOAELs/LOAELs, and allometric scaling.
- Proposal for deriving effective dose (EDx)-based TRVs using all available qualified toxicity data.
Main Results:
- Existing TRV methods, such as reliance on NOAELs/LOAELs and inappropriate extrapolation, are not supported by current science.
- Inability to define the probability of adverse outcomes and inappropriate use of hazard quotients are significant issues.
Conclusions:
- Future TRV derivation should utilize all qualified toxicity data and incorporate measures of variation.
- Shifting to EDx-based TRVs and moving beyond hazard quotients will improve the reliability of wildlife risk assessments and contaminant evaluations.
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