Photosynthetic Toxicity of Enrofloxacin on Scenedesmus obliquus in an Aquatic Environment

Aquaculture facilities are a potential source of antibiotics in aquatic environments, having adverse effects on the algae species. In this study, the toxicity induced by enrofloxacin (ENR) on the algae Scenedesmus obliquus was evaluated. The uptake of ENR and the change in the growth and photosynthesis of algae were analyzed. At the exposure doses of 10-300 mu g/L, the accumulated levels of ENR in algae were 10.61-18.22 mu g/g and 12.09-18.34 mu g/g after 48 h and 96 h of treatment, respectively. ENR inhibited the growth of algae, with a concentration for 50% effect of 119.74 mu g/L, 53.09 mu g/L, 64.37 mu g/L, and 52.64 mu g/L after 24 h, 48 h, 72 h and 96 h of treatment, respectively, indicating the self-protection and repair ability of algae in a short period of time. Furthermore, the chlorophyll contents decreased in all treatment groups, and the photosynthetic system II parameters decreased in a dose-dependent manner under ENR stress, suggesting that ENR caused a disorder in the electron transport of the photosynthesis of algae, and the carbon fixation and assimilation processes were thus damaged. These results indicate that ENR poses a considerable risk to aquatic environments, affects the carbon sinks, and even has an adverse effect on human health.

Automated summary

Aquaculture facilities can contaminate aquatic environments with antibiotics, which can have negative effects on algae species. This study evaluated the toxicity of enrofloxacin on Scenedesmus obliquus algae. The results showed that enrofloxacin accumulated in the algae and inhibited their growth and photosynthesis. Furthermore, enrofloxacin disrupted the electron transport and carbon fixation processes in algae, posing a considerable risk to aquatic environments and potentially impacting human health.