Lead (Pb2+) causes chlorophyll related changes and oxidative damage in Chlorella ellipsoides (Chlorophyceae)

The increasing production of anthropological wastes containing heavy metals has resulted to their discharge and contamination into freshwater ecosystems. Hence, the effects of heavy metals are of health concern for aquatic biodiversity. This study investigated the short term effects of Pb2+ (0.0, 10, 20, 40, 60, 80 and 100 µg.L-1) on the biomass (cell density, chlorophyll a, b) and antioxidant (catalase (CAT), superoxide dismutase (SOD), guiacol peroxidase (GPx), glutathione reductase (GRx), and malondialdehyde (MDA)). Chlorella ellipsoides (Chlorophyceae) was sensitive to Pb2+, a significant decrease (p < 0.05) of chlorophyll a and b was observed with increasing concentrations of Pb2+. Antioxidant Catalase, SOD, GPx and GRx relatively decreased significantly (p < 0.05) after exposure of microalga to Pb2+. However, MDA increased significantly (p < 0.05) after microalgae was exposed to Pb2+. The finding of this study indicates that exogenous concentrations are harmful for the welfare of C. ellipsoides. This study is important as it demonstrates the potential impact of Pb2+ on microalgae. Field studies in African freshwater biodiversity and monitoring of aquatic ecosystems are recommended to assess the level and impact of Pb2+ in aquatic ecosystems.