Pharmaceuticals may disrupt natural chemical information flows and species interactions in aquatic systems: ideas and perspectives on a hidden global change

Over the last decades, anthropogenic activities have discharged into the environment many manmade chemicals. There is a rising concern regarding pharmaceutical products and their spread into the environment (e.g. Kümmerer 2008). Due to the enormous quantities consumed, anti-inflammatories, antibiotics, anti-depressives, hormones and blood lipid regulators are found in almost all aquatic environments (Kolpin et al. 2002; Loos et al. 2009). Most pharmaceuticals tend to enter the aquatic environment continuously (but see Sacher et al. 2008 for seasonal exception) in contrast to other pollutants such as herbicides and insecticides which are applied only at specific times related to the life cycle of the target organism, or in response to observed pest outbreaks (Rosi-Marshall and Royer 2012). Pharmaceuticals are designed to be biologically active at very low concentrations and end up in surface waters either unchanged, or as active metabolites/polar conjugates, mostly via municipal wastewater and agricultural discharges (Boxall et al. 2012).