State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163 Xianlin Avenue, Nanjing 210046, PR China.
Environ Sci Process Impacts. 2013 Apr;15(4):860-9. doi: 10.1039/c3em30288a.
This work set out to study the effects of cadmium (Cd) in sediments on the antioxidant enzyme activities in the digestive gland of Asian clam Corbicula fluminea and to explore the potential for applying these responses to evaluate the Cd-contaminated sediment. Additionally, diffusive gradients in thin-films (DGT) technique was used to predict the response of its antioxidant defense system. The sediments, collected from Taihu Lake, were spiked with Cd at different concentrations (0.72, 0.91, 1.62, 2.59, 11.2, 20.4 and 40.6 mg kg(-1), dry weight). Asian clam was cultivated for 28 days. Concentrations of Cd in the body of Asian clam had a good relationship with concentrations of Cd in overlying water and sediments, as measured by DGT. Cd affected these biochemical parameters significantly, especially for superoxide (SOD), peroxidase (POD) and glutathione (GSH), which began to show higher sensitivity and have a significant difference in low dosage (0.91 mg Cd kg(-1)) compared with blank. Contents of MDA and MT, which were induced by Cd, increased with the increasing Cd concentration in sediments and reached peak values at 11.2 and 20.4 mg kg(-1), respectively, after 28 days exposure. All of these results suggested that biochemical responses cooperated in detoxifying and maintaining cellular metabolic homeostasis. The R(2) of regression analysis between the contents of MT and the concentrations of Cd measured by DGT, in sediments and soft body were 0.71, 0.94 and 0.88 after 28 days exposure. This suggested that DGT measurement could predict the response of MT. Cd accumulation, GSH and MT were indispensable biomarkers and the MDA content and DGT appeared to be promising biomarkers. The results clearly indicated that Cd could induce oxidative stress in the digestive gland of Asian clam. The combination of biomonitors with DGT can obtain different information about Cd bioavailability and confirm the significance of applying a suite of biomarkers rather than a selective index to assess the sublethal effect. It also offered theoretical methods for the prediction of sediment Cd pollution.
本研究旨在探讨底泥中镉（Cd）对三角帆蚌消化腺抗氧化酶活性的影响，并探讨将这些反应应用于评价 Cd 污染底泥的潜力。此外，还采用扩散梯度薄膜（DGT）技术预测其抗氧化防御系统的响应。这些沉积物取自太湖，分别用不同浓度（0.72、0.91、1.62、2.59、11.2、20.4 和 40.6mgkg-1，干重）的 Cd 进行了加标处理。三角帆蚌在这些沉积物中养殖了 28 天。通过 DGT 测量，三角帆蚌体内的 Cd 浓度与上覆水和沉积物中的 Cd 浓度有很好的相关性。Cd 对这些生化参数有显著影响，尤其是超氧化物歧化酶（SOD）、过氧化物酶（POD）和谷胱甘肽（GSH），它们在低剂量（0.91mgCdkg-1）时就开始表现出更高的敏感性，并与空白组有显著差异。Cd 诱导的 MDA 和 MT 含量随着沉积物中 Cd 浓度的增加而增加，在 28 天暴露后分别在 11.2 和 20.4mgkg-1 时达到峰值。所有这些结果表明，生化反应协同作用于解毒和维持细胞代谢的动态平衡。28 天后，MT 含量与 DGT 测量的沉积物和软体动物中 Cd 浓度之间的回归分析的 R2 分别为 0.71、0.94 和 0.88。这表明 DGT 测量可以预测 MT 的反应。Cd 积累、GSH 和 MT 是必不可少的生物标志物，MDA 含量和 DGT 似乎是有前途的生物标志物。结果清楚地表明，Cd 可诱导三角帆蚌消化腺的氧化应激。将生物监测器与 DGT 相结合，可以获得关于 Cd 生物有效性的不同信息，并证实应用一系列生物标志物而不是选择性指标来评估亚致死效应的重要性。它还为底泥 Cd 污染的预测提供了理论方法。
