Predicted and measured concentrations for selected pharmaceuticals in UK rivers: implications for risk assessment.

Predicted environmental concentrations for five commonly used pharmaceuticals were calculated using data from the UK Department of Health according to risk assessment guidelines proposed by the European Agency for the Evaluation of Medicinal Products. Surface waters from the South-East of England were analysed and results were compared with predicted concentrations and findings from other studies from the UK and Europe. It was found that the efficacy of these predictions varied and was hampered by a shortage of data for many of the drugs. Ibuprofen, paracetamol and salbutamol were detected and quantified in all locations sampled. Ibuprofen was consistently found at the highest concentrations (up to 3 microg l(-1)). Levels up and downstream of two wastewater treatment works were compared in order to investigate the link between sewage discharge and environmental concentrations of pharmaceuticals. Results from one site demonstrated a considerable increase in concentrations of ibuprofen, salbutamol and paracetamol downstream from the treatment works; however, no link was established for a second works.