Methodology To Determine Risk Of Chemicals In Rivers Under Data Uncertainty

The goal of probabilistic ecological risk assessment (PERA) is to estimate the likelihood and the extent of adverse effects occurring to humans and ecological systems due to exposure(s) to substances. It is based on the comparison of an exposure concentration distribution (ECD) with a species sensitivity distribution (SSD) derived from chronic toxicity data. This PERA framework was completed by also incorporating the uncertainty inherent to risk assessment. A case study on the pesticide atrazine in the surface waters of Flanders illustrates the completion. The availability of confidence intervals on the calculated risks is important for the decision-maker since these express how reliable the risk assessment is.