Invertebrates differentially bioaccumulate pharmaceuticals: Implications for routine biomonitoring

Surface water quality monitoring programs have been developed to examine traditional contaminants, such as persistent organic pollutants (POPs). However, urbanization, which is increasing around the world, is increasing discharge of treated wastewater and raw sewage in many regions. Pharmaceuticals and their metabolites represent typical markers of such trajectories in urbanization. We selected an ongoing monitoring program, which was designed for routine surveillance of nonionizable POPs in different aquatic matrices, to examine the occurrence of 67 pharmaceuticals and their metabolites in water and multiple bioindicator matrices: benthic invertebrates, juvenile fish, and adult fish (plasma and muscle tissue) from ten river systems with varying levels of watershed development. In addition, we placed zebra mussels and passive samplers in situ for a fixed period. A statistically significant relationship between pharmaceutical levels in passive samplers and biota was found for caged zebra mussels and benthic invertebrates, while only a few pharmaceuticals were identified in fish matrices. Invertebrates, which have received relatively limited study for pharmaceutical bioaccumulation, accumulated more pharmaceuticals than fish, up to thirty different substances. The highest concentration was observed for sertraline in zebra mussels and telmisartan in benthic invertebrates (83 and 31 ng/g ww, respectively). Our results across diverse study systems indicate that ongoing surface water quality monitoring programs, which were originally designed for traditional organic pollutants, need to be revised to account for bioaccumulation dynamics of pharmaceuticals and other ionizable contaminants. Aquatic monitoring programs routinely examine accumulation of nonionizable organic pollutants; however, we identified that these efforts need to be revised to account for bioaccumulation of ionizable contaminants, which reached higher levels in invertebrates than in fish.