Occurrence and ecotoxicity of cytostatic drugs 5-fluorouracil and methotrexate in the freshwater unionid Elliptio complanata

• Published in: Comparative biochemistry and physiology. Toxicology & pharmacology 2021-06, Vol.244, p.109027, Article 109027
• Main Authors: Kleinert, Christine, Poirier-Larabie, Sylvie, Gagnon, Christian, André, Chantale, Gagné, François
• Format: Article
• Language: English
• Subjects: Cytostatic drug; Freshwater mussels; Genotoxicity; Oxidative stress
• ISSN: 1532-0456; 1878-1659
• DOI: 10.1016/j.cbpc.2021.109027

Municipal effluents continuously release cytostatic drugs with unknown consequences in aquatic organisms. The purpose of the study was to examine the sublethal toxicity of 2 commonly-found cytostatic drugs 5-fluouracile (5-FLU) and methotrexate (MTX) to endemic Elliptio complanata freshwater mussels. The mussels were exposed of each drugs at 0, 4, 20 and 100 μg/L for 96 h t 15 °C. After the exposure period, glutathione S-transferase (GST) and dehydrofolate reductase (DHFR) activities, DNA damage and lipid peroxidation (LPO) were determined. The drugs were detected in mussel tissues with no evidence of accumulation with either drugs. The drug 5-FLU gave a larger spectrum of effects than MTX such as increased DHFR, decreased LPO and DNA strand breaks (repair activity) suggesting that the mussels were metabolically hindered and reduced DNA repair activity. The drug MTX only increased DHFR activity in the gonad. Hence, the data suggest that these drugs are biologically active in freshwater mussels and based on the reported maximum levels of these drugs in municipal effluents, the observed effects are likely in sessile freshwater mussel species downstream urban sources of pollution. [Display omitted] •Freshwater mussels were exposed to methotrexate and 5-fluouracil in the laboratory.•These cytostatic drugs were detected in tissues but with no bioaccumulation after 96 h.•Both drugs produced changes in dehydrofolate metabolism and decreased DNA strand breaks.