中国农田土壤重金属富集状况及其空间分布研究

在统计有关我国农田土壤重金属相关文献数据的基础上,探讨了我国农田土壤重金属Pb、Cd、Cu、Zn和Cr的空间富集现状.收集到有关土壤Pb、Cd、Cu、Zn和Cr含量的研究分别为173、138、156、139、140个.首先剔除异常值,然后利用剩余样本进行克里金插值,并统计各省地区重金属含量平均值.结果表明我国重金属空间分布具有明显的区域特征,西南地区土壤重金属含量较高,其他地区相对较低;与分省的土壤背景值相比较,农田土壤Pb和Cd的含量明显高于背景值.土壤Pb在云南省超出背景值最高,为背景值的1.91倍;Cd在辽宁省超出背景值最高,为23.02倍;Zn在云南省富集最为严重,是背景值的1.55倍,Cu最高的是广东省,达到背景值的2.92倍.

Spatial Distribution and Accumulation of Heavy Metal in Arable Land Soil of China

Based on the domestic and foreign published papers about soil heavy metal contents, the present study explored the spatial variations of heavy metal contents in agricultural soil in China. Totally, 173 studies on soil Pb, 138 on Cd, 156 on Cu, 139 on Zn and 140 on Cr were collected. Firstly, the abnormal values were selected and removed, then the spatial distributions were obtained through Kriging method and the average values in the provinces were calculated. Results show that the spatial distributions of heavy metals have obvious regional characteristics and the southwest part of China has relatively high heavy metal concentrations in soils. Compared with the background value of soil heavy metal concentrations, nearly all of the provinces have higher Pb, Cd, Cu and Zn concentrations. Pb and Cd have the most obviously higher values than the background values. The highest difference of Pb concentration is in Yunnan Province with 1.91 times of the background, and the highest Cd difference is in Liaoning Province with 23.04 times of the background; The highest Zn enrichment is in Yunnan, with 1.55 times of the background; and the highest Cu difference with 2.92 times of the background value.