Predicting concentrations of cytostatic drugs in sewage effluents and surface waters of Catalonia (NE Spain)

Abstract

Cytostatic drugs, used in chemotherapy, are excreted unchanged by urine and feces or modified as metabolites. Elimination of these drugs in wastewater treatment plants (WWTPs) is often incomplete and residues reach surface water. Their presence in the natural environment depends on consumption patterns, excretion fraction and the effectiveness of the wastewater treatment. This study compiled the total consumption of cytostatic drugs in Catalonia (NE Spain) and provides data on the occurrence and risk of anticancer drugs in the aquatic environment by calculating predicted environmental concentrations (PECs). PECs were estimated using publicly available consumption data in the period of 2010-2012, published or calculated excretion values and wastewater elimination rates for a suite of 132 compounds. This allows predicting the range of concentrations in effluent wastewaters and receiving waters. Out of the 132 cytostatics, mycophenolic acid and hydroxycarbamide had a PEC value higher than 10ngL(-1). PECs were compared with MECs (measured environmental concentrations) to evaluate the reliability of the estimation. A risk assessment was conducted to determine the potential adverse effects of cytostatics in the environment. All the risk quotients calculated using EC50 in Daphnia magna were below 1, showing no significant risk.

Keywords: Cytostatic drugs; Predicted environmental concentrations; Risk assessment; River; WWTP effluent.