Institute of Surface-Earth System Science, School of Earth System Science, Tianjin Key Laboratory of Earth Critical Zone Science and Sustainable Development in Bohai Rim, Tianjin University, Tianjin 300072, China.
Institute of Surface-Earth System Science, School of Earth System Science, Tianjin Key Laboratory of Earth Critical Zone Science and Sustainable Development in Bohai Rim, Tianjin University, Tianjin 300072, China.
J Environ Sci (China). 2023 Jul;129:202-212. doi: 10.1016/j.jes.2022.09.009. Epub 2022 Sep 16.
The excessive accumulation of potentially toxic metals (Pb and Cd) in coastal wetlands is among the main factors threatening wetland ecosystems. However, the effects of water table depth (WTD) on the risk and binding mechanisms of potentially toxic metals in sediments remain unclear. Here, sediments from different WTD obtained from a typical coastal wetland were evaluated using a newly developed strategy based on chemical extraction methods coupled with high-resolution spectroscopy. Our findings indicated that the WTD of the coastal wetland fluctuates frequently and the average enrichment factor for Pb was categorized as minor, whereas Cd enrichment was categorized as moderate. High-resolution spectroscopy techniques also demonstrated that organic functional groups and partly inorganic compounds (e.g., Fe-O/Si-O) played a vital role in the binding of Pb and Cd to surface sediments. Additionally, mineral components rather than organic groups were mainly bound to these metals in the bottom sediments. Collectively, our findings provide key insights into the potential health effects and binding characteristics of potentially toxic metals in sediments, as well as their dynamic behavior under varying sediment depths at a microscale.
沿海湿地中潜在有毒金属（如 Pb 和 Cd）的过度积累是威胁湿地生态系统的主要因素之一。然而，水层深度（WTD）对沉积物中潜在有毒金属的风险和结合机制的影响尚不清楚。在这里，我们使用一种新开发的基于化学提取方法与高分辨率光谱相结合的策略，评估了来自典型沿海湿地的不同 WTD 的沉积物。我们的研究结果表明，沿海湿地的 WTD 频繁波动，Pb 的平均富集因子被归类为轻微，而 Cd 的富集被归类为中度。高分辨率光谱技术还表明，有机官能团和部分无机化合物（例如 Fe-O/Si-O）在 Pb 和 Cd 与表层沉积物结合中发挥了重要作用。此外，在底层沉积物中，主要是矿物成分而不是有机基团与这些金属结合。总的来说，我们的研究结果为深入了解沉积物中潜在有毒金属的潜在健康影响和结合特征及其在微观尺度下不同沉积物深度下的动态行为提供了关键的见解。
