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1H a/b/c - Pesticides, pharmaceuticals, perfluoroalkylated substances, antibiotics (WEP/39) Community and population responses of freshwater zooplankton to pharmaceutical mixtures. Wilson, Christian1, Sanderson, Hans1, Brian, Richard1, Johsnon, David1, Sibley, Paul1, Solomon, Keith1, 1 Centre for Toxicology, University of Guelph, Guelph, Ont, Canada ABSTRACT- Complex mixtures of pharmaceuticals are increasingly detected in world surface waters. The effects on non-target aquatic organisms have not been well characterized. Laboratory and field studies were conducted to assess direct and indirect effects, and also to determine differences between acute and chronic exposure to several pharmaceuticals. In a 50-day microcosm study, a mixture of 8 pharmaceuticals at 5 concentrations was examined: sertraline, carbamazepine, levofloxacin, sulfamethoxazole, trimethoprim, atorvastatin, acetaminophen and caffeine. Every 7 days, plankton samples were obtained from each 12 000 L treatment pond. Zooplankton samples were analysed by light transmission microscopy, identifying all taxa in 3 mL aliquots. Data were evaluated using CANOCO, a multivariate analysis tool providing Principal Response Curves (PRC). PRCs graphically describe and summarize information on communities and populations. Accompanying species weight data provides information on the contribution of various species to the PRC. The zooplankton PRC showed treatment dependant response. Faunal shifts were evident in the aquatic community over time. The taxonomic diversity was greatly reduced at high concentrations. Overall, community dynamics were heavily affected. Laboratory studies indicated 48-hour lethality for mixture components, using Daphnia magna . This analysis revealed that sertraline, an antidepressant and selective serotonin reuptake inhibitor (SSRI), was the most potent actor in the microcosm mixture [LC50 = 0.2 mg/L]. Related compounds fluoxetine and clomipramine showed similar potency. Antibiotic components demonstrated no acute daphnid toxicity in the laboratory up to 10 mg/L. Sub-lethal chronic effects of all tested components will be discussed in relation to the microcosm studies. Key words: aquatic microcosms, pharmaceuticals, freshwater ecosystems, zooplankton |
