Aquatic ecotoxicity of an antidepressant, sertraline hydrochloride, on microbial communities

Sertraline hydrochloride (Ser-HCl), a widely used antidepressant, becomes an aquatic contaminant via metabolic excretion and improper disposal; however, it is unknown how Ser-HCl affects aquatic microbial communities. The present study investigated the effects of Ser on the structures of aquatic microbial communities via high-throughput sequencing analyses. Ser-HCl treatment inhibited the growth of two model algae (the green alga, Chlorella vulgaris, and the cyanobacterium, Microcystis aeruginosa) and decreased the chlorophyll a (Chl-a) concentration in the microcosm to reduce the photosynthetic efficiency. High-throughput sequencing analyses showed that exposure to Ser-HCl disturbed the balance of cyanobacteria species by stimulating the growth of specific cyanobacteria. Among eukaryotes, the richness as well as the diversity indices were significantly enhanced after 5 days of Ser-HCl treatment but sharply decreased with exposure time. Nucleariida occupied an absolute majority (97.83%) within the eukaryotes, implicating that Ser-HCl disturbed the ecological equilibrium in microcosms. Ser-HCl will continue to be an environmental contaminant due to its wide usage and production. Our current study clarified the potential ecological risk of Ser-HCl to aquatic microorganisms. These findings suggest that more attention should be given to the negative effects of these bioactive pollutants on aquatic environments.