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

Mordecai Gana

Abstract
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.

Keywords
Chlorella ellipsoides; Stress; Toxicant; Antioxidative.

DOI
10.21472/bjbs.061412

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