Ecological Risk Assessment

Quantitative Ecological Risk Assessment comprises a probabilistic assessment of the hazard posed by any stressor to biota within an impacted habitat. In simple terms, measurements of the concentration of pollution within a habitat are used to generate a mathematical distribution with a mean and standard deviation. Similarly, biological dose-response data, such as toxicity data or measures of contaminant concentrations that have been observed to adversely affect plants and animals likely to exist in the habitat, are also used to generate a distribution. The two distributions are then compared to determine the number of species likely to be affected, the extent to which the toxicant concentrations are likely to exceed acceptable criteria and also the degree to which the contamination needs to be reduced in order to achieve acceptably low levels of environmental impact.

ANSTO has developed a code, AQUARISK, that can perform such calculations. It can also compare the pollutant levels with regulatory or user-defined concern levels. The code is designed particularly for metals in water, but it is sufficiently general to be suitable for almost any pollutant in any habitat (eg pesticides in soil).