Department of Natural Resources Management and Geoinformatics, Khallikote University, At G-Max Builiding on NH-16, Kanisi, Dist. Ganjam, Berhampur, Odisha, 761008, India.
Gujarat Institute of Desert Ecology (GUIDE), P.O. # 83, Opp. Changleshwar Temple, Mundra Road, Bhuj, 370001, India.
Environ Monit Assess. 2019 Nov 1;191(12):715. doi: 10.1007/s10661-019-7913-2.
Mobilization of metals in wetland ecosystems is a function of the behaviour of a specific metal species and is dependent largely on the prevailing micro-environmental conditions. Apparently, five different chemical forms of metals are known with varying affinity to binding sites, mobility, bioavailability and toxicity. Quantification of these forms of metals in the soils is imperative in predicting their biogeochemical fate and toxicity. In this context, we examined the association of Cu, Pb and Zn, with various geochemical phases in the soil profile of wetland system of Keoladeo National Park, a Ramsar site in India. The assessment covered the soil profile until 100 cm depth at every 25-cm intervals. Different operationally defined geochemical phases in the soil at different depths were examined during the study for respective metal concentrations. Hydrous oxides of Fe-Mn were the major carrier for all the three metals and the fraction associated with exchangeable phase was the least. The low organic matter content in the soil seems to be influencing the metal association with the organic matter (OM-S) phase, which was also a less preferred carrier for metals. For Cu (5.8-78.4%) and Pb (33.5-88.5%), Fe-Mn hydroxide phase was an important binding site and for Zn (31.02-79.03%), it was the silicate mineral matrix (RES phase). This suggests the importance of micro-environmental conditions in the wetland bed such as redox and pH in mobilization of metals. As metals such as Pb have high eco-toxicological potential, an assessment of fractional concentrations of metals provides insights into their mobility and bioavailability in aquatic ecosystems. This aids wetland managers to develop appropriate strategy to maintain quality of inflow water, the single most crucial factor for a wetland ecosystem, and thus controls the micro-environmental conditions.
湿地生态系统中金属的迁移是特定金属物种行为的功能，主要取决于普遍的微环境条件。显然，已知有五种不同化学形态的金属，它们与结合位点的亲和力、迁移性、生物可利用性和毒性不同。定量分析这些形态的金属在土壤中的含量对于预测它们的生物地球化学命运和毒性至关重要。在这种情况下，我们研究了印度基拉迪奥国家公园（拉姆萨尔湿地）湿地系统土壤剖面中 Cu、Pb 和 Zn 与各种地球化学相的关系。评估涵盖了土壤剖面，直至 100 厘米深，每隔 25 厘米间隔一次。在研究过程中，检查了不同深度下不同操作定义的土壤地球化学相中的相应金属浓度。水合铁锰氧化物是所有三种金属的主要载体，与可交换相结合的部分最少。土壤中低有机质含量似乎影响了金属与有机质（OM-S）相的结合，有机质相也是金属的次要载体。对于 Cu（5.8-78.4%）和 Pb（33.5-88.5%），Fe-Mn 氢氧化物相是一个重要的结合位点，而对于 Zn（31.02-79.03%），它是硅酸盐矿物基质（RES 相）。这表明湿地床的微环境条件（如氧化还原和 pH 值）在金属的迁移中很重要。由于 Pb 等金属具有很高的生态毒性潜力，因此评估金属的分数浓度可以深入了解它们在水生生态系统中的迁移性和生物可利用性。这有助于湿地管理者制定适当的策略来维持流入水的质量，这是湿地生态系统的关键因素，从而控制微环境条件。
