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.

中文翻译：

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回水蛤 Meretrix casta 中环境相关浓度铜的毒性的综合响应

摘要 铜被释放到水生环境中是人类活动的结果，例如采矿和含铜杀虫剂和化肥的径流。这可能对居住在沿海水体或河口的生物的健康构成威胁。因此，本研究旨在评估河口死水蛤 Meretrix casta 中与环境相关的铜浓度的毒性。在实验设置中，蛤蜊在水中暴露于五种浓度的 CuCl2（0.5、1.0、1.5、2.0 和 2.5 μg/L）中 15 天。基因毒性的生物标志物（微核试验和彗星试验）、氧化应激（过氧化氢酶和丙二醛试验）、乙酰胆碱酯酶活性和条件指数被用来研究铜对蛤的影响。遗传毒性、氧化应激、发现乙酰胆碱酯酶活性和条件指数在所有浓度组中都不显着，表明如此低浓度的铜不能诱导任何毒性反应。然而，使用综合生物标志物反应指数，观察到浓度依赖性增加，表明这些生物标志物反应的整合可以提供有关水生栖息地铜污染早期迹象的信息。Meretrix casta 可能被用作监测河口环境中铜污染的哨兵物种。观察到浓度依赖性增加，表明这些生物标志物反应的整合可以提供有关水生栖息地铜污染早期迹象的信息。Meretrix casta 可能被用作监测河口环境中铜污染的哨兵物种。观察到浓度依赖性增加，表明这些生物标志物反应的整合可以提供有关水生栖息地铜污染早期迹象的信息。Meretrix casta 可能被用作监测河口环境中铜污染的哨兵物种。