Ecological risk assessment of the presence of pharmaceutical residues in a French national water survey.

In this study, we focused on the list of 33 chemicals that was established through a French national prioritisation strategy. Assessing the potential risks to the environment was a step-wise procedure: (i) we determined the Predicted Environmental Concentration (PEC) of all molecules measured in the national survey based on the highest recommended dose used, (ii) we used the Measured Environmental Concentration (MEC) and the Predicted No-Effect Concentration (PNEC) to establish the Risk Quotient (RQ) based on either a PEC/PNEC (estimated risk) or MEC/PNEC (real risk) ratio. The risk assessment was performed using a binary ecological classification suggesting that appreciable risk is likely (RQ⩾1). Of the 15 molecules quantified in the survey, 12 had a PEC higher than the action limit value of 0.01µg/L. According to the EU Guideline, environmental risk was estimated as likely for the following five compounds: acetaminophen (RQ=1.6), ibuprofen (RQ=600), diclofenac (RQ=15), oxazepam (RQ=2.1) and carbamazepine (RQ=3.2). Only ibuprofen was identified as posing real environmental risk based on its MEC (RQ=1.9).