Low biodegradability of fluoxetine HCl, diazepam and their human metabolites in sewage sludge-amended soil

Abstract

Background, aim, and scope The European Union banned disposal of sewage sludge (SS) at sea in Europe in 1998. Since that time, the application rate of SS to land has risen significantly and is set to rise further. Fifty-two percent of SS was disposed to land in the UK in 2000. Land application is, thus, possibly an important transport route for SS-associated organic chemicals into the environment. There are now over 3,000 different pharmaceutical ingredients in use in the EU and many enter sewage systems. Possibly as a result, the last decade has seen an increase in reports of pharmacologically active compounds in the environment (e.g. in watercourses, open ocean and soils). Surprisingly, there is still a significant lack of knowledge of the transport and fate of pharmaceuticals in the environment, particularly in soils. The present project, therefore, investigated the susceptibility to microbial degradation of the selective serotonin re-uptake inhibitor, Prozac® (fluoxetine HCl), and the 1,4-benzodiazepine, Valium® (Diazepam) and their major human metabolites (norfluoxetine HCl, temazepam and oxazepam) in short-term (60 day) bacterial liquid cultures derived from UK SS-amended soil and of fluoxetine HCl in a longer-term (270 day) SS-amended soil culture.