Behavioural toxicity of organic chemical contaminants in fish: application to ecological risk assessments (ERAs)

Chemical pollutants rarely attain acutely lethal concentrations in nature; thus the majority of their effects are expected to be sublethal. Estimation of the likelihood of effects from exposures to sublethal concentrations of contaminants in effluent plumes downstream of point sources poses a challenge when conducting ecological risk assessments (ERAs). This is an issue for regulatory agencies worldwide. This paper reviews the importance and availability of information on behavioural toxicity and identifies opportunities for its inclusion in ERAs. One of the major advantages of using data on behavioural effects is that they are more sensitive indicators of potential for impacts on survival in the field than are measures of lethality. Indications from available data for fish suggest that behavioural effects of organic contaminants often occur at concentrations 1 to 2 orders of magnitude lower than those found to elicit mortality. As a result, it is believed that the use of data on behavioural toxicity in ERAs could benefit the assessment process a great deal, allowing for the consideration of more ecologically significant and protective hazard and exposure scenarios.