(PW121) Effects assessment of antidepressant pharmaceuticals in acute laboratory assays and semi-field microcosm experiments.
Johnson, D1, Brain, R1, Wilson, C1, Sanderson, H1, Bestari, K1, Sibley, P1, Solomon, K, 1 University of Guelph Centre for Toxicology, Guelph, ON, Canada
ABSTRACT- Widespread occurrence of multiple pharmaceuticals in surface waters has been identified. Included among these pharmaceuticals was the selective serotonin reuptake inhibitor (SSRI) antidepressant fluoxetine. To address the issue of the presences of SSRIs in the aquatic environment and generate data for later use in risk assessment, laboratory acute toxicity assays were performed on algae (Pseudokirchneriella subcapitata, Chlorella vulgaris, Anabaena flos-aquae, and Microcystis aeruginosa) and larval fish (Pimephales promelas and Oryzias latipes) using three commonly prescribed SSRIs: fluoxetine, sertraline and fluvoxamine. 96 h algal growth EC50s were between 100 and 1000 
g/L for each algal species. 96 h survival LC50s were between 100 and 1000 g/L for each fish species. Once laboratory acute toxicity thresholds were determined chronic (35 d) semi-field experiments using a mixtures of the above SSRIs were performed in 12 m3 aquatic microcosms. The mixtures contained equal parts fluoxetine, sertraline and fluvoxamine at 0, 12.5, 25, 50 and 100 g/L (n=3 microcosms each). Fish (P. promelas (n=16, 8 breeding pairs), Lepomis gibbosus (n=10), and Carassius auratus (n=10)) were housed separately in each microcosm to measure reproductive and non-reproductive endpoints. Fecundity and percent hatch were determined for P. promelas. Non-reproductive endpoints measured were fitness factors, gonad somatic index (GSI), hepatic somatic index (HSI) and total carcass fat. Reproductive endpoints, GSI and HSI were not significantly affected by the treatment. Fitness factor and total carcass fat were significantly reduced from control with EC50 values ranging from 50 to 1000 g/L (non-linear regression) depending on the species of fish. While fitness factor and total carcass fat may have been directly affected by the treatment, since serotonin has a role in feeding and satiety, it is also possible that response is due to impacted zooplankton and phytoplankton communities. Further research is required before a final assessment regarding effects of these pharmaceuticals on algae and fish can be concluded.
Key words: Fish, Antidepressant Pharmaceutical, Microcosm, Algae