title: Complex mixtures, complex responses: Assessing pharmaceutical mixtures using field and laboratory approaches.
abstract: Pharmaceuticals are present in low concentrations (<100 ng/L) in most municipal wastewater effluents but may be elevated locally because of factors such as input from pharmaceutical formulation facilities. Using existing concentration data, the authors assessed pharmaceuticals in laboratory exposures of fathead minnows (Pimephales promelas) and added environmental complexity through effluent exposures. In the laboratory, larval and mature minnows were exposed to a simple opioid mixture (hydrocodone, methadone, and oxycodone), an opioid agonist (tramadol), a muscle relaxant (methocarbamol), a simple antidepressant mixture (fluoxetine, paroxetine, venlafaxine), a sleep aid (temazepam), or a complex mixture of all compounds. Larval minnow response to effluent exposure was not consistent. The 2010 exposures resulted in shorter exposed minnow larvae, whereas the larvae exposed in 2012 exhibited altered escape behavior. Mature minnows exhibited altered hepatosomatic indices, with the strongest effects in females and in mixture exposures. In addition, laboratory-exposed, mature male minnows exposed to all pharmaceuticals (except the selective serotonin reuptake inhibitor mixture) defended nest sites less rigorously than fish in the control group. Tramadol or antidepressant mixture exposure resulted in increased splenic T lymphocytes. Only male minnows exposed to whole effluent responded with increased plasma vitellogenin concentrations. Female minnows exposed to pharmaceuticals (except the opioid mixture) had larger livers, likely as a compensatory result of greater prominence of vacuoles in liver hepatocytes. The observed alteration of apical endpoints central to sustaining fish populations confirms that effluents containing waste streams from pharmaceutical formulation facilities can adversely impact fish populations but that the effects may not be temporally consistent. The present study highlights the importance of including diverse biological endpoints spanning levels of biological organization and life stages when assessing contaminant interactions.
authors.affiliation: Aquatic Toxicology Laboratory, St. Cloud State University, St. Cloud, Minnesota, USA.
authors.forename: Heiko L
authors.initials: HL
authors.lastname: Schoenfuss
authors.affiliation: National Water Quality Laboratory, US Geological Survey, Denver, Colorado, USA.
authors.forename: Edward T
authors.initials: ET
authors.lastname: Furlong
authors.affiliation: New York Science Center, US Geological Survey, Troy, New York, USA.
authors.forename: Pat J
authors.initials: PJ
authors.lastname: Phillips
authors.affiliation: New York Science Center, US Geological Survey, Troy, New York, USA.
authors.forename: Tia-Marie
authors.initials: TM
authors.lastname: Scott
authors.affiliation: Iowa Water Science Center, US Geological Survey, Iowa City, Iowa, USA.
authors.forename: Dana W
authors.initials: DW
authors.lastname: Kolpin
authors.affiliation: Laboratory for Immunology, St. Cloud State University, St. Cloud, Minnesota, USA.
authors.forename: Marina
authors.initials: M
authors.lastname: Cetkovic-Cvrlje
authors.affiliation: Laboratory for Immunology, St. Cloud State University, St. Cloud, Minnesota, USA.
authors.forename: Kelsey E
authors.initials: KE
authors.lastname: Lesteberg
authors.affiliation: Aquatic Toxicology Laboratory, St. Cloud State University, St. Cloud, Minnesota, USA.
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Rearick
mesh_terms: D000818:Animals; D003530:Cyprinidae / Q000502:physiology*; D064420:Drug-Related Side Effects and Adverse Reactions; D005260:Female; D007814:Larva / Q000187:drug effects / Q000502:physiology; D008099:Liver / Q000187:drug effects / Q000648:ultrastructure; D008297:Male; D004364:Pharmaceutical Preparations / Q000032:analysis*; D014819:Vitellogenins / Q000097:blood; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*
chemical_list: D004364:Pharmaceutical Preparations; D014819:Vitellogenins; D014874:Water Pollutants, Chemical
keywords: Behavioral toxicology; Effluent; Fathead minnows; Immunology; Pharmaceuticals