Predicting chemical effects on birds: a critical literature review.

Howe, Paul D (1997). Predicting chemical effects on birds: a critical literature review. BPhil thesis The Open University.

DOI: https://doi.org/10.21954/ou.ro.0000f5ec

Abstract

The effects of chemicals on birds has created a great deal of public concern and scientific debate. A wealth of information on species distribution, breeding numbers and population changes has provided a good basis for identifying environmental problems after the event. However, the difficulty lies in using such information for predicting possible chemical impacts in the future. Standard laboratory toxicity testing is carried out as a routine requirement for both national and international regulatory authorities, and the prediction of effects is still centred around these tests. .Development work has concentrated on test regimes and field validation, but little attention has been focused on the interpretation of the data in the light of the other factors which influence the survival and reproduction of wild birds. Standard and non standard tests, field trials, monitoring and risk assessment methods and approaches are reviewed. It is concluded that laboratory testing has an important place in the prediction of the effects of chemicals on wild bird populations. However, such tests must be seen merely as a means of screening chemicals for potential effects rather than realistic models of events in the natural world. Test design needs to be varied, .and risk assessment flexible, with significant scope for expert judgement. Risk assessment of chemicals should be fate-led to minimize the unnecessary use of laboratory animals by identifying the distribution and availability of chemicals in the environment before testing for effects. Preliminary risk assessment conclusions should be validated in the field. Multidisciplinary studies involving testing, field trials, monitoring and risk assessment should ideally be carried out; disciplines such as toxicology, environmental chemistry, ecology, population dynamics, ethology, physiology and land use geography all have a part to play.