Cytotoxicity and Genotoxicity of Malachite Green on Non-Target Aquatic Organisms: Chlorella Pyrenoidosa and Daphnia Magna

Abstract

Malachite green (MG), a water-soluble, N-methylated diaminotriphenylmethane dye, is released into the aquatic environment due to its extensive use in aquaculture, leather, food and textile industries. In USA and Europe, although MG is banned in food fishes because of its significant health risk, the dye is persistently used in various countries. Toxicity studies on other non-target aquatic organisms are extremely rare, in spite of its identification as an environmental contaminant. In the current research, an effort has been made to understand its environmental toxicity using Chlorella pyrenoidosa and Daphnia magna as model. We have investigated MG-induced cellular and morphological alterations in chlorella and acute immobilization assay in daphnia. Our data revealed that MG induces genotoxicity in C. pyrenoidosa, causing DNA damage and cytotoxicity by altering protein profiles and elevating reactive oxygen species level, respectively. Also, scanning electron microscopy confirms MG toxicity as it induces pore formation in the cell membrane. When grown in presence of MG, effective concentration (EC50) for D. magna was observed to be 0.77 mg/l, along with its accumulation in the abdominal cavity. These findings indicate that MG is toxic to C. pyrenoidosa (primary producer) and D. magna (primary consumer) of the aquatic food chain. Knowledge of the toxicity of potentially toxic compounds on aquatic organisms is significant, as it allows evaluating the consequences that these pollutants can have on the aquatic biota. Therefore, our study could potentially raise awareness of the long-ignored ecotoxic effects of MG and its implication on the regulation of its industrial application.