Toxic Effects of Aquatic Pharmaceuticals on Chlorella sp. in Kazakhstan

Abstract

Pharmaceuticals are crucial for human health, but their release into the environment through various means can contaminate groundwater, surface waters, soil, and microorganisms. The contamination of water by pharmaceuticals in Kazakhstan is not well-studied. Understanding the influence of pharmaceutical ingredients on the ecosystem and public health is a key area of ecological research. Globally, researchers are investigating the risks posed by pharmaceuticals in water sources and their environmental effects. This study uses Chlorella sp. to test the impacts of pharmaceuticals on aquatic biota, examining growth rate and growth inhibition. The study followed OECD Research Method 201. Pharmaceuticals with high pollution potential in Kazakhstan's water resources, including ketoconazole, terbinafine, drotaverine hydrochloride, telmisartan, benzylpenicillin, and azithromycin, were studied. Azithromycin was found to be the most toxic to Chlorella sp. (0.33 ± 0.05 mg/L), while amoxicillin had the least toxic effect (853.54 ±0.27mg/L). Azithromycin has significant effect to Chlorella sp. resistance, especially in smallest experimental concentrations. At 0.2 mg/L, azithromycin nearly halved the growth rate compared to the control, growth inhibition was over 87% at 0.15 mg/L (r2=0.89). Chlorella sp. showed minimal sensitivity to high concentrations of amoxicillin, with slight decrease of growth (2% at 1 mg/L, 57% at 1000 mg/L).