Determining the risks to the aquatic environment
The comparison of contaminant concentrations to existing guideline values, or measures of potential biological impacts are often not sufficient to make final decisions.
An ecological risk assessment (ERA) process is required to evaluate the likelihood of adverse ecological effects occurring as a result of exposure to one or more stressors.
ERA provides environmental managers with an approach for considering available scientific information along with other factors (social, political, economic) in selecting a course of action. Risk assessment differs from hazard and impact assessment in that it provides a direct link between exposure and effects, enabling the comparison and prediction of risk and uncertainty associated with various scenarios.
However, combining and evaluating different lines of evidence (LoEs) using weight-of-evidence (WoE) approaches to enable ERA decisions, can be complex and requires increasing expertise as the number of LoEs increases.
Evaluating and refining methods for environmental risk assessment (ERA)
In conjunction with our research developing and evaluating different LoEs for assessing the presence and potential effect of contaminants in the environment, we have been evaluating methods for combining and ranking LoEs within WoE frameworks for the purpose of ERA.
We work with industry and government through many stages of the ERA process, for example the critical initial problem formulation stage to assist with identifying stressor sources and characteristics, exposure pathways, habitats, receptors, effects, environmental values, and measurable assessment endpoints. Background monitoring data are gathered and data gaps identified to construct a conceptual model of cause and effect pathways. These have been captured in the management framework of the revised Australian and New Zealand water quality guidelines (ANZG, 2018).
Providing assessment solutions for industry and government
Using our broad knowledge of stressor-effect relationships, we undertake or guide clients in using measured or predicted concentrations of stressors and effects data to work through deterministic approaches (hazard quotients) or probabilistic methods for ERA decisions. This process enables estimation of risk (likelihood and consequence) and associated uncertainty for communication to stakeholders.