Arsenic and heavy metals pollution along a salinity gradient in drained coastal wetland soils: Depth distributions, sources and toxic risks
Arsenic and heavy metals pollution along a salinity gradient in drained coastal wetland soils: Depth distributions, sources and toxic risks
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排干沿海湿地土壤中沿盐度梯度的砷和重金属污染：深度分布、来源和毒性风险
DOI：
10.1016/j.ecolind.2018.08.026
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发表时间：
2019-01-01
影响因子：
6.9
通讯作者：
Liu, Xinhui
中科院分区：
文献类型：
--
作者：
Bai, Junhong;Zhao, Qingqing;Liu, Xinhui
盐离子对河口湿地中金属/类金属的毒性、迁移和迁移有重要影响。在黄河口滨海湿地裸地（B）、柽柳湿地（T）、盐地碱蓬湿地（S）和芦苇湿地（P）4个采样点，沿沿着盐度梯度采集土壤样品，深度为30 cm。砷（As）和重金属（即，通过对重金属（Cd、Cr、Cu、Pb、Zn）含量的测定，分析了重金属的含量、深度分布、来源及毒性风险。结果表明，As和重金属含量总体上随盐度的增加而下降。所有样品中的砷浓度超过了阈值效应水平（TELS）值，低于可能的影响水平（PELS）。所有土壤样品中Cd、Pb和Zn的浓度均低于TEL值，而Cr和Cu的浓度在几个土壤样品中均处于TELs-PELs范围内。根据地积累指数（I-geo），Cd在B、S和P点表现为未污染至中度污染，而其他重金属在所有土壤中均未观察到污染。一般来说，较高的I-geo值的镉观察在这些网站具有较低的盐度。As和重金属在B和T两个站位的平均毒性单位（TU）值为Cr > As > Zn > Cu > Pb > Cd，在S和P两个站位的TU值为As > Cr > Zn > Cu > Pb > Cd。相关分析表明，As和重金属与电导率、砂粒含量、Cl-、Cl-/SO 42-比值和Mg 2+呈显著负相关（P <0. 05），与土壤含水量、粘粒和粉粒含量、土壤有机碳呈显著正相关（P <0. 05）。多变量分析表明，这些重金属来源于同一来源，而As也有另一来源。研究结果可为滨海湿地污染控制和生态系统健康保护提供参考。
Salt ions can affect the toxicity, mobility and transfer of metals/metalloids in estuarine wetlands. Soil samples were collected to a depth of 30 cm along a salinity gradient at four sampling sites, including bare land (B), Tamarbc Chinensis wetlands (T), Suaeda salsa wetlands (S) and Phragmites australis wetlands (P) in drained coastal wetlands in the Yellow River Estuary, China. Arsenic (As) and heavy metals (i.e., Cd, Cr, Cu, Pb and Zn) were measured to investigate their levels, depth distributions, sources and toxic risks. The results showed that As and heavy metals generally showed a decline with increasing salinities. Arsenic concentrations in all samples exceeded the threshold effects levels (TELs) value and were below the probable effects levels (PELs). The concentrations of Cd, Pb and Zn in all soil samples were below TEL values, while Cr and Cu concentrations were grouped to the range of TELs-PELs in several soil samples. According to the geoaccumulation index (I-geo) Cd exhibited unpolluted to moderate pollution at Sites B, S and P, whereas no pollution for other heavy metals were observed in all soils. Generally, higher I-geo values for Cd were observed at those sites with lower salinities. The average toxic unit (TU) values of As and heavy metals at Sites B and T followed the order Cr > As > Zn > Cu > Pb > Cd, and the followed order was As > Cr > Zn > Cu > Pb > Cd at Sites S and P. As and Cr showed higher contributions to the TUs than other metals. Correlation analysis showed that As and heavy metals were negatively correlated with electrical conductivity (EC), sand content, Cl-, Cl-/SO42- ratio and Mg2+ (P < 0.05), while were positively correlated with soil moisture, clay and silt contents and soil organic carbon (SOC) (P < 0.05). The mutivariate analysis indicated that these heavy metals originated from the same source, while As also had another source. The findings of this work can contribute to pollution control and ecosystem health conservation of coastal wetlands.