Berlin Highlights—Extrapolation within Wildlife Toxicology
John Elliott, Environment Canada and Nico van den Brink, Alterra Wageningen UR
When assessing risks of environmental contaminants to wildlife, data are always limited. That may be, in part, due to limited resources, but generally, relevant species-specific information on sensitivity, exposure conditions, food-web dynamics and additional site-specific information is lacking. These challenges may be overcome by conducting extensive field studies, but that is not always or even generally feasible. Therefore, alternative approaches are needed. Alternative approaches that use information from, for instance, other species, sites or time periods.
New chemical or site-specific risk assessments demand rigorous evaluation of hazards to wildlife, especially threatened or endangered species. For such approaches, methods for extrapolation of information are essential. An approach, for instance, to derive toxic threshold levels based on species sensitivity, distribution curves may be well established to interpolate toxicity data among species. However, its use for wildlife is generally restricted due to lack of enough relevant toxicity data from different species on the specific compound in question. On the other hand, the use of lab species as indicators for wildlife species may also be limited due to its single species approach.
At our session in Berlin, our platform speakers informed us of the range of extrapolation techniques being applied. One study of seabird exposure to PBDEs used a combination of geolocator telemetry and stable isotopes to examine variability in contaminant exposure between the breeding and wintering grounds of great skuas. In France, the impacts of remediation at a former gold mining site were examined through an intensive field study of heavy metals in small mammals. On the west coast of Canada, the potential impact of residual PCB contamination at the population level in river otters was investigated using fecal DNA genotyping techniques and radio-telemetry. Finally, the problem of rodenticide impacts on non-target wildlife in Spain and New Zealand was examined, particularly the difficulties in extending limited toxicity data to a range of avian wildlife, including birds of prey and even penguins.
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