Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
Environ Pollut. 2018 Jan;232:514-522. doi: 10.1016/j.envpol.2017.09.081. Epub 2017 Oct 5.
Soil particulate organic matter (POM) has rapid turnover and metal enrichment, but the interactions between organic matter (OM) and metals have not been well studied. The present study aimed to investigate changes in the OM concentration and composition of the POM fraction and their corresponding effects on metal distribution and extractability in long-term polluted paddy soils. Soil 2000-53 μm POM size fractions had higher contents of C-H and C=O bonds, C-H/C=O ratios and concentrations of fulvic acid (FA), humic acid (HA), cadmium (Cd) and zinc (Zn) than the bulk soils. Cadmium and Zn stocks in soil POM fractions were 24.5-27.9% and 7.12-16.7%, respectively, and were more readily EDTA-extractable. Compared with the control soil, the 2000-250 μm POM size fractions had higher organic carbon concentrations and C/N ratios in the polluted soils. However, there were no significant differences in the contents in C-H and C=O bonds or C-H/C=O ratios of POM fractions among the control, slightly and highly polluted soils. In accordance with the lower contents of C=O bonds and FA and HA concentrations, the Cd and Zn concentrations in 250-53 μm POM size fractions were lower than those in 2000-250 μm POM size fractions. Enrichment of Cd in POM fractions increased with increasing soil pollution level. These results support the view that changes in the OM concentration and the size and composition of POM fractions play a key role in determining the distribution of Cd and Zn in paddy soils.
土壤颗粒有机质（POM）具有快速周转和金属富集的特点，但有机质（OM）与金属之间的相互作用尚未得到很好的研究。本研究旨在调查长期污染稻田土壤中 POM 部分的 OM 浓度和组成变化及其对金属分布和可提取性的相应影响。2000-53μm POM 粒径土壤具有更高的 C-H 和 C=O 键、C-H/C=O 比值以及富里酸（FA）、胡敏酸（HA）、镉（Cd）和锌（Zn）浓度。土壤 POM 部分中的 Cd 和 Zn 储量分别为 24.5-27.9%和 7.12-16.7%，且更易被 EDTA 提取。与对照土壤相比，污染土壤中 2000-250μm POM 粒径部分的有机碳浓度和 C/N 比值较高。然而，在对照、轻度和重度污染土壤中，POM 部分的 C-H 和 C=O 键含量或 C-H/C=O 比值均无显著差异。由于 C=O 键和 FA、HA 浓度较低，250-53μm POM 粒径部分的 Cd 和 Zn 浓度低于 2000-250μm POM 粒径部分。POM 部分中 Cd 的富集随着土壤污染程度的增加而增加。这些结果支持这样一种观点，即 OM 浓度以及 POM 部分的大小和组成的变化在决定 Cd 和 Zn 在稻田土壤中的分布方面起着关键作用。
