Growth inhibition, oxidative stress and characterisation of mortality in green algae under the influence of beta-blockers and non-steroidal anti-inflammatory drugs.

Bisoprolol and ketoprofen are widely used pharmaceuticals in medical treatment hence these substances are occurring in wastewaters and in water environment. This research investigated the toxic effects of bisoprolol and ketoprofen on two microalgae taxa, Chlorella vulgaris and Desmodesmus armatus. The results showed that both drugs inhibited the growth of the species tested and induced a decrease in chlorophyll a content compared to controls. Ketoprofen turned out to be harmful to algae as the half maximal effective concentration (EC) values (14 days) were 37.69 mg L for C. vulgaris and 40.93 mg L for D. armatus. On the other hand, for bisoprolol, the EC values were greater than the established NOEC, 100 mg L. Bisoprolol and ketoprofen induced oxidative stress in the tested microorganisms, as indicated by changes in the activities of antioxidant enzymes. Exposure to 100 mg L of drugs significantly increased the activity of catalase, peroxidase and superoxide dismutase. Fluorescence microscopy showed that both medicaments changed the cells' morphology. There was atrophy of chlorophyll in the cells, moreover, dying multinuclear cells and cells without nuclei were observed. In addition, there were atrophic cells, namely cells that lacked nuclei and chlorophyll. Profile area analyses showed that bisoprolol and ketoprofen treated C. vulgaris cells were approximately 4 and 2 times greater compared to control ones. Our experimental findings highlight the ecotoxicological threats for aquatic primary producers from bisoprolol and ketoprofen and provide insight into the characteristics of their death.