Diclofenac In The Environment

The anti-inflammatory drug diclofenac’s legacy in the environment came into the public eye in 2004 when the collapse of an endangered vulture population in Pakistan was tied to the birds’ feeding on medicated cattle. Several studies have since shown that diclofenac and its metabolites, after human use, slip through wastewater treatment plants and persist in the environment. Researchers led by Leif Kronberg of Finland’s Åbo Akademi University are reporting that diclofenac and its metabolites can accumulate in rainbow trout livers at levels that can cause cellular changes (Environ. Sci. Technol., DOI: 10.1021/es903402c). Those levels were recently quantified by Charles R. Tyler of the University of Exeter, in England, and coworkers (Environ. Sci. Technol. 2010, 44, 2176). The two reports combined suggest that fish living downstream from wastewater treatment plants may be at risk. However, the news on diclofenac is not all bad. A team led by Willy Verstraete of Ghent University, in Belgium, reports that manganese oxides produced by bacteria are better at breaking down diclofenac than is synthetic MnO₂ because the bacteria can reoxidize the formed Mn²⁺ (Environ. Sci. Technol., DOI: 10.1021/es9027327). Biological MnO_x is a promising technology for removing diclofenac from wastewater in treatment plants, Verstraete says.