徐州农田土壤重金属空间分布及来源分析

    Sources and Spatial Distributions of Heavy metals in Xuzhou Farmland Soils

    • 摘要: 采集徐州89个农田表层(0~20 cm)土壤样品并测试土壤中Hg、As、Pb、Cd、Cu、Cr、Zn和Ni 8种重金属含量,运用多元统计分析和地统计分析方法研究土壤重金属主要来源,并探讨土壤重金属空间分布规律。结果表明,研究区农田土壤重金属含量均未超过GB 15618-2018《土壤环境质量农用地土壤污染风险管控标准(试行)》中水旱轮作农田土壤风险筛选值,满足耕作要求。Hg、Pb、Cu和Cr平均含量高于徐州/江苏土壤背景值,存在一定富集趋势。从土壤种植类型角度分析,发现水稻种植土壤中Cd、As、Cr、Zn和Ni含量相对较高。不同类型土壤中暗棕壤Hg含量相对较低,黄壤Pb含量较高。土壤中Cd、As、Cu、Zn和Ni含量受母质影响较大,Pb和Hg含量主要受人为活动影响较大。As、Zn、Cr和Ni含量峰值在铜山区和沛县北部及贾汪区西部地区分布较多,Pb、Cd和Cu含量峰值出现在邳州地区,Hg含量峰值分布与城区人类活动有关。

       

      Abstract: The concentrations of 8 metals (Hg, As, Pb, Cd, Cu, Cr, Zn and Ni) were measured in the surface soil (0-20 cm) from 89 farmlands in Xuzhou, China. Sources and spatial distributions of the heavy metals were analyzed using multivariate approaches and the ordinary Kriging method. Major conclusions are as follows. The mean concentrations of all 8 heavy metals in the soil were below the critical limits of the national safety standards, therefore meeting the farming requirement. The mean concentrations of Hg, Pb, Cu and Cr were higher than the background values of Xuzhou and Jiangsu, which suggested a potential metal contamination. In terms of the soil type, Cd, As, Cr, Zn and Ni in paddy soil were relatively enriched among different soil plantations. The concentrations of Hg in dark brown soil was relatively low and Pb in yellow soil was high among 4 types of soil. Principal component analysis and correlation analysis indicate that the sources of Cd, As, Cu, Zn and Ni were mainly parent materials, whereas Pb and Hg have anthropogenic sources. High concentrations of As, Zn, Cr and Ni were noted in the north of Tongshan District and Peixian County and in the west of Jiawang District. The concentrations of Pb, Cd and Cu peak was in Pizhou, while the highest concentration of Hg was likely related to human activities in urban areas.

       

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