ABSTRACT
Copper is released into the aquatic environment as a consequence of anthropogenic activities such as mining and runoffs of copper-containing pesticides and fertilisers. This may pose a threat to the health of the organisms inhabiting coastal water bodies or estuaries. The present study was therefore carried out to assess the toxicity of environmentally relevant concentrations of copper in the estuarine backwater clam Meretrix casta. In the experimental setup, clams were exposed to five concentrations of CuCl2 (0.5, 1.0, 1.5, 2.0 and 2.5 μg/L) for 15 days in water. Biomarkers of genotoxicity (Micronucleus test and comet assay), oxidative stress (Catalase and malondialdehyde assays), acetylcholinesterase activity and condition index were employed to study the effects of copper on the clams. Genotoxicity, oxidative stress, acetylcholinesterase activity and condition index were found to be non-significant in all the concentration groups indicating that such low concentrations of copper were unable to induce any toxic response. However, using the Integrated Biomarker Response index, a concentration-dependent increase was observed indicating that the integration of these biomarker responses could give information on early signs of copper contamination in aquatic habitats. Meretrix casta could potentially be used as a sentinel species for monitoring copper contamination in the estuarine environment.
Disclosure statement
No potential conflict of interest was reported by the authors.
Acknowledgements
The authors wish to express their gratitude to the University Grants Commission (UGC) for providing the Maulana Azad National Fellowship (F1-17.1/2013-14/MANF-2013-14-CHR-GOA-25375). The authors also wish to thank Ms. Moreska Costa for her assistance in proofreading the article.
Notes on contributors
Dr. Avelyno H. D’Costa is an Assistant Professor in the Department of Zoology, Dhempe College of Arts & Science affiliated to Goa University. His research interests include toxicology, molecular biology and genetics and his specialization is ecotoxicology.
Ms. Swizzle Furtado is an Assistant Professor in the Department of Zoology, Carmel College for Women affiliated to Goa University. Her research interests include molecular biology, genetics and biochemistry.
Ms. S. S. Greeshma is currently pursuing her final year of Bachelor of Science in the subject of Zoology in Dhempe College of Arts and Science affiliated to Goa University. Her research interests include molecular biology and genetics.
Dr. S. K. Shyama is a Professor (Retd.) and former Head of the Department of Zoology, Goa University. His expertise is in toxicology and animal genetics and his specialization is genotoxicology.