A Data Based Perspective on the Environmental Risk Assessment of Human Pharmaceuticals Il — Aquatic Risk Characterisation

Environmental risk assessment (ERA) evaluates the likelihood that adverse ecological effects result from exposure to a substance. It therefore requires a consideration of both exposure and effects in relevant environmental compartments. The exposure assessment considers the fate of a substance released to the environment and predicts the environmental concentration or PEC (“predicted environmental concentration”). The effects assessment considers data relating to the effects of the substance upon representative biota and uses such data to predict the no-effect concentration or PNEC (“predicted no-effect concentration”) for the various environmental compartments (i.e. surface waters, sediment, soil, etc.). The PEC and PNEC are combined in order to characterise the risk, i.e. calculation of the PEC/PNEC ratio (see Fig. 25.1). Decisions regarding the safety of the substance depend upon the value of this quotient.