Toxic effect of copper on soil microalgae: experimental data and critical review

Microalgae are sensitive bioindicators in assessing the toxic effects of heavy metals. In this regard, the effects of prolonged exposure to copper on biotechnologically important soil microalgae have not been sufficiently studied. The work aimed to study copper’s action on soil microalgae: Vischeria magna , Botrydiopsis sp., and Tetracystis sp. in a 28-day experiment with different initial cell densities (× 10 3 and × 10 6 cell/mL) using CuSO 4 and Cu(CH 3 COO) 2 as the source of copper. It was found that the toxic effect of copper depends on its concentration, initial density of algae cells in testing, and the chemical source of copper. This research revealed that Tetracystis sp . had the highest resistance to copper, which withstood copper concentrations up to 50 mg/L. Botrydiopsis sp . and V. magna were resistant to copper concentrations of 30 mg/L and 5 mg/L, respectively. Copper appeared less toxic for the test with a higher cell density (× 10 6 cell/mL). It was also found that the toxic effect of copper was manifested at lower concentrations in experiments with CuSO 4 compared to ones using Cu(CH 3 COO) 2 . The results of this study provide a better understanding of the effects of copper on soil microalgae species and their potential for biotechnological production using heavy metal waters, bioremediation, and monitoring of algae diversity, especially in soils contaminated by heavy metals.