工业型城乡交错区农业土壤Cu、Zn、Pb和Cd的空间分布及影响因素研究

SPATIAL DISTRIBUTIONS OF Cu,Zn,Pb AND Cd IN AGRICULTURAL SOILS OF INDUSTRY-BASED PERI-URBAN REGIONS

在江苏省无锡市工业型城乡交错区,选择8 km2区域,采集119个土壤样品,对土壤Cu、Zn、Pb、Cd及其有效态含量的空间分布和影响因素进行探讨。结果表明:该区土壤Cu、Zn、Pb、Cd含量和变异系数都明显增加,土壤有效态重金属含量与相应的全量重金属含量具有显著相关性。土壤Cu、Zn、Cd空间变异主要受到工业影响,但由于该区工业类型的多样性和工厂分布的分散性,Cu、Zn、Cd空间分布模式并不相同。本区土壤Pb的分布与工厂分布的相关性不大,但随与城市距离增加而降低。公路和土地利用与土壤重金属含量的关系表现不明显。该区工业污染对土壤重金属空间变异的影响可能掩盖了公路和土地利用等的影响,建议在城乡交错区合理安排工业布局以控制土壤受重金属污染的范围。

In the industry-oriented peri-urban region of Wuxi, Jiangsu Province, concentrations of total and DTPA extractable Cu, Zn, Pb and Cd were determined of 119 topsoil samples collected from an area of 8 km^2and factors dominating spatial distributions of these elements were studied. Concentrations and coefficient of variation of soil heavy metals in this area were found increasing and so were significant positive correlations between concentrations of DTPA extractable metals and of their respective totals. Spatial variations of Cu, Zn and Cd in the soils were induced mainly by the industry therein. However the patterns of their spatial distribution hardly indicated any similarity probably because of the dispersiveness in distribution and diversity in type of the industrial plants in the study area. Concentrations of Pb were found high in the soil close to the city and decreased with distance away from the city. Highway and land use didn＇t show any close relationship with the variation of heavy metal concentrations in the soil, which was obviously obscured by the impact of the industry. It is, therefore, strongly recommended that a reasonable and orderly layout be made for industrial plants, so as to control the scope of soils polluted with heavy metals.