Biological Oceanography Division, CSIR-National Institute of Oceanography, Dona Paula, Goa, 403004, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
CSIR-National Institute of Oceanography-Regional Centre, Mumbai, 400 053, India.
Chemosphere. 2021 Sep;278:130338. doi: 10.1016/j.chemosphere.2021.130338. Epub 2021 Mar 22.
Impact of varying concentrations and counts of toxic metals and indigenous bacteria on antioxidative defense system in edible oyster, Saccostrea cucullata, collected from four tropical estuarine systems of Goa (west coast of India), are presented in this study. Relatively high abundance of bacteria was estimated from the oysters especially during monsoon season (June-September). Density of total and fecal coliforms were about 24 times higher in the organism than the surrounding water (average TC: 4360 and FC: 3475 MPN 100 ml). Sedimentary Cd, Pb, and Hg concentrations varied from 0.12 to 0.48, 19.28-102.48, and 0.03-0.13 mg kg (dry wt.) while, bioaccumulation of Cd, Pb, and Hg in the oysters ranged from 5.17 to 10.6, 0.18-7.99, and 0.06-0.22 mg kg (dry wt.) respectively. Higher degree of pollution and moderate ecotoxicological risks with increasing toxicity (36-37%) was observed in two of the tropical estuaries. Biomarker response in the oysters was somewhat inconsistent with pollution load in the estuarine systems. Elevated environmental stress was observed during pre-monsoon (March-May) followed by the monsoon period. Sedimentary metals were identified as predominant inducers of antioxidative defence system in oysters from the study areas. This study suggests that, biomarker can be useful in assessing the combined effects of metal and bacterial contaminations on native oysters and in evaluating environmental quality in tropical estuarine systems.
本研究探讨了来自印度西海岸果阿四个热带河口系统的食用牡蛎（Saccostrea cucullata）中，不同浓度和数量的有毒金属和土著细菌对其抗氧化防御系统的影响。特别是在季风季节（6 月至 9 月），从牡蛎中估计出相对较高丰度的细菌。总大肠菌群和粪大肠菌群的密度在生物体中比周围水中高约 24 倍（平均 TC：4360 和 FC：3475 MPN 100ml）。沉积物中的 Cd、Pb 和 Hg 浓度分别为 0.12-0.48、19.28-102.48 和 0.03-0.13mgkg（干重），而牡蛎体内的 Cd、Pb 和 Hg 生物积累量分别为 5.17-10.6、0.18-7.99 和 0.06-0.22mgkg（干重）。在两个热带河口，观察到更高程度的污染和中等生态毒性风险，毒性增加了 36-37%。在河口系统中，生物标志物的反应与污染负荷有些不一致。在季风前（3 月至 5 月）期间观察到了较高的环境压力，随后是季风期。沉积物中的金属被确定为研究区域牡蛎抗氧化防御系统的主要诱导物。本研究表明，生物标志物可用于评估金属和细菌污染对本地牡蛎的综合影响，并评估热带河口系统的环境质量。
