Partitioning and geochemical fractions of heavy metals from geogenic and anthropogenic sources in various soil particle size fractions
Partitioning and geochemical fractions of heavy metals from geogenic and anthropogenic sources in various soil particle size fractions
复制标题
各种土壤粒径部分中地源和人为来源的重金属的分配和地球化学部分
DOI：
10.1016/j.geoderma.2017.10.013
复制
发表时间：
2018-02-15
期刊：
影响因子：
6.1
通讯作者：
Dong, Liming
中科院分区：
文献类型：
--
作者：
Liu, Guannan;Wang, Juan;Dong, Liming
土壤颗粒大小对重金属在土壤中的富集有显著影响。然而，土壤胶体颗粒的尺寸效应对重金属的分配和地球化学形态的研究很少。本研究分别从江西、河北和广西壮族自治区采集了4种重金属污染土壤。从土壤中分离出5个粒级（> 10、10 ~（-1）、1 ~ 0.45、0.45-0.2和< 0.2 μ m），研究了镉（Cd）、镉（Cr）、铜（Cu）、锰（Mn）、镍（Ni）、铅（Pb）和锌（Zn）的分配和地球化学形态。对于JX、GX和GX'土壤，地源元素Cr、Ni和GX土壤Cr、Ni、Mn与背景值相当，而人为元素Cr、Ni、Mn则高于背景值。在仅受Pb污染的HB土壤中，Cd、Cr、Cu、Mn、Ni和Zn为地源重金属。土壤胶体中大部分重金属的含量高于土壤粗颗粒中的含量，土壤重金属在土壤胶体中的分配趋势与人为重金属在土壤胶体中的分配趋势无显著差异。重金属在土壤各粒级中的分配与土壤颗粒组成（有机质、铁铝氧化物和粘粒矿物）密切相关。对于地源重金属（Cr、Ni），土壤颗粒的硅酸盐结晶结构中的残留态比例很高，不同粒径组土壤的地球化学形态具有可比性，而人为重金属（Cu、Mn、Pb、Zn）的生物有效态比例则很低，随着土壤粒径的减小，各组分所占的比例逐渐减小，其它组分所占的比例逐渐增大。这一结果表明，更多的人为重金属以其稳定的形式存在于细颗粒土壤中。Fe、Al和TOC与人为重金属的生物有效性分数均呈负相关，且大多数呈显著或极显著相关，表明高含量的OM和Fe/Al氧化物稳定了土壤细颗粒中的人为重金属。
The size of soil particles can significantly affect the enrichment of heavy metals in soil. However, the size effect of soil particles in colloidal dimension on the partitioning and geochemical fractions of heavy metals has been rarely studied. In this study, four soils, polluted by several heavy metals, were collected from Jiangxi (JX) and Hebei (HB) Provinces and Guangxi Zhuang Autonomous Region (GX and GX') in China, respectively. Five size fractions (> 10, 10-1, 1-0.45, 0.45-0.2 and < 0.2 mu m) were separated from the studied soils to investigate the partitioning and geochemical fractions of cadmium (Cd), cadmium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn). For JX, GX and GX' soils, Cr and Ni in JX and GX' soils and Cr, Ni and Mn in GX soil, as geogenic elements, were comparable with their background values; whereas other heavy metals, as anthropogenic elements, were higher than their background values. For the HB soil that was only polluted by Pb, Cd, Cr, Cu, Mn, Ni and Zn were the geogenic heavy metals. Generally, the contents of most heavy metals in the soil colloids were higher than that in coarse soil particles, and the partitioning tendencies with particle size were not significantly different between geogenic heavy metals and anthropogenic heavy metals. The partitioning of heavy metals in various soil particle size fractions was closely related to the soil particle compositions, such as OM, Fe/Al oxides and clay minerals. For geogenic heavy metals (Cr, Ni), the proportion of the residual fraction, which is imbedded in the silicate crystalline structures of soil particles, was very high, and the geochemical fraction patterns of the various soil particle size fractions were comparable, whereas the bioavailable fraction of anthropogenic heavy metals, such as Cu, Mn, Pb and Zn, decreased with decreasing soil particle size and the proportion of other fractions increased with decreasing size. This result indicates that more anthropogenic heavy metals exist in their stable form in fine soil particles. Correlations between Fe, Al and TOC and the bioavailable fraction of anthropogenic heavy metals were all negative, and most were significant or very significant indicating that high contents of OM and Fe/Al oxides stabilize anthropogenic heavy metals in fine soil particles.