北京市桃主产区土壤重金属空间结构特征及来源

Spatial structure characteristics and origins of soil heavy metals in the main producing area for peach in Beijing

运用地统计学和主成分分析法对北京市桃主产区土壤Hg、As、Cd、Cr、Pb 5种重金属的含量、空间结构特征及来源进行研究.结果表明:5种重金属含量平均值均达到国家土壤环境质量一级标准,变异系数在0.16～0.29之间; Hg、As、Cr具有强烈的空间自相关;Cd和Pb具有中等空间相关性;Hg、Cr的最佳拟合模型为高斯模型,As、Cd、Pb的最佳拟合模型为指数模型.Pb、As、Cr、Hg含量的空间分布受土壤母质、地形等结构性因素影响显著.Cd含量的空间分布受土壤母质、地形等结构性因素和土地利用等随机因素的共同影响.综上,调查区内土壤重金属大部分保持自然背景水平,适宜作物生长.

The contents, spatial structure characteristics, resources of mercury(Hg), arsenic(As), cadmium(Cd), chromium(Cr), plumbum(Pb)from 122 topsoil samples in the main producing area for peach in Beijing were systematically analyzed by Geostatistical methods and principal component analysis. The results showed that the average contents of 5 heavy metals met the standard Ⅰ of China Soil Environment Quality Standard, with variation coefficients of all heavy metals ranging from 0.16 to 0.29. In addition, the nugget showed that Hg, As and Cr had strong spatial autocorrelation, while Cd and Pb was moderately correlated. The best fitting model for Hg and Cr was Gaussian model, and it was the exponential model for As, Cd, and Pb. The spatial distribution of Pb, As, Cr and Hg were significantly influenced by structural factors such as soil parent material, altitude, etc. The spatial distribution of Cd content was influenced by structural and random factors such as soil parent material, altitude, land use, etc. In conclusion, the contents of soil heavy metals in this survey area mostly maintain natural background level and are suitable for crop growth.