Zhejiang University of Finance and Economics Dongfang College, Haining 314408, China.
School of Earth Sciences and Engineering, Hohai University, Nanjing 211110, China.
Int J Environ Res Public Health. 2021 Sep 19;18(18):9876. doi: 10.3390/ijerph18189876.
The distribution of heavy metal pollution in cultivated land is closely related to the quality of the cultivated land. In this study, 533 soil samples were collected from cultivated land in the Yangtze River delta region in China for Cd, Pb, and Hg analyses. Spatial statistical analysis was used to study the heavy metal pollution in the cultivated land, and the driving forces of heavy metal distribution in different cultivated land quality subdivisions were analyzed with GeogDetector. The conclusions are as follows: (1) Among the three heavy metals in the study area, the coefficient of variation of Cd is the largest, and that of Pb is the smallest. The proportion of Cd and Hg exceeding the standard value (the standard of level two in GB 15618-2018) is relatively large, both of which are 5%; (2) From the perspective of the spatial distribution of soil heavy metal pollution, only four counties (CX, HN, WY, and LH) were free of heavy metal pollution. Soil heavy metal pollution in AJ, SY, QJ, and DS counties is relatively serious, and the pollution may come from agricultural activities, manufacturing, and prevalent coastal shipping industries in these counties; (3) The heavy metal pollution levels of cultivated land with different quality levels are different. The high-quality cultivated land has no high contamination, while the medium and the general cultivated land both have high contamination. High contamination is related to Cd for medium and general cultivated lands, and to Hg in only general cultivated land; (4) The main driving factors of heavy metal concentration in cultivated soil were GDP, followed by soil organic matter, and pH. These results indicate that the spatial distribution of heavy metal concentration in cultivated soil was affected by the level of economic development, followed by the ecological environment, indicating that human activities had a critical impact on the ecological environment of cultivated land.
耕地重金属污染分布与耕地质量密切相关。本研究采集了中国长江三角洲地区 533 个耕地土壤样本，进行 Cd、Pb 和 Hg 分析。采用空间统计分析方法研究耕地重金属污染状况，并利用 GeogDetector 分析不同耕地质量细分区重金属分布的驱动因素。结论如下：（1）在所研究区域的三种重金属中，Cd 的变异系数最大，Pb 的变异系数最小。超标（GB 15618-2018 二级标准）的比例相对较大，均为 5%；（2）从土壤重金属污染的空间分布来看，只有 4 个县（CX、HN、WY 和 LH）没有重金属污染。AJ、SY、QJ 和 DS 县的土壤重金属污染较为严重，污染可能来自这些县的农业活动、制造业和盛行的沿海航运业；（3）不同质量水平耕地的重金属污染水平不同。优质耕地无污染，而中、低质量耕地均有高污染。中、低质量耕地的高污染与 Cd 有关，仅在低质量耕地与 Hg 有关；（4）耕地土壤重金属浓度的主要驱动因素是 GDP，其次是土壤有机质和 pH。这些结果表明，耕地土壤重金属浓度的空间分布受经济发展水平的影响，其次是生态环境，表明人类活动对耕地生态环境有重要影响。
