Ecotoxicology of Antimicrobial Pharmaceutical and Personal Care Products in Illinois Rivers and Streams

In urban areas wastewater treatment plant (WWTP) effluent can represent a significant component of freshwater ecosystems, and WWTP effluent can be a point source for a variety of pollutants, including pharmaceuticals and personal care products (PPCPs). We analyzed two field sites in the Chicago region: (1) an urban river receiving effluent from a large WWTP; and (2) a suburban river receiving effluent from a smaller WWTP. At both sites WWTP effluent had negative effects on the abundance and diversity of benthic bacterial communities. We then investigated the potential effects of one specific PPCP, triclosan, a broad-spectrum antimicrobial compound that is incorporated into numerous consumer products. We developed a method for the quantification of triclosan in sediment based on pressurized fluid extraction (PFE) by accelerated solvent extraction (ASE) and used this method to demonstrate that triclosan is present in streams in the Chicago region and that triclosan concentrations in stream sediments increased with degree of urbanization. Finally, we conducted a field survey and a lab-scale model stream experiment and demonstrated that triclosan exposure is linked to increases in triclosan resistance and decreases in biodiversity within benthic bacterial communities. These results indicate that widespread use of triclosan could have negative ecological consequences.