贵州省典型污染区土壤重金属的污染特征分析

为了解贵州省不同来源典型污染区土壤重金属的污染特征,为重金属污染防治提供科学依据,对贵阳市、六盘水市、毕节市、都匀市等11个研究区耕地土壤进行调查,采用电感耦合等离子体质谱(ICP-MS)对189个土壤样品的Cr、Cu、Zn、As、Cd和Pb等6种重金属进行测定,并运用聚类分析和主成分分析等方法对结果进行分析。结果表明:开阳县金中镇土壤污染最轻,综合污染因子为0.897,属于磷质石灰岩地球化学背景下Cd较高的土壤类型;处于轻度污染水平的研究区是贵阳市青岩镇二关村、白云区曹官村、花溪区久安乡和清镇市后午;受污灌影响,贵阳市乌当区土壤已处于中度污染水平,特征污染因子是Cd;水城县倮摩村、赫章县野马川、大湾镇安乐村、幸福村和都匀市坝固村分别受到铅锌矿和煤矿开采的影响,属重度污染区,坝固村由于存在独立镉矿床,镉单项污染因子为77.88,综合污染指数达到56.22。主成分分析结果显示,研究区内重金属Cd和Cu是背景值较高的典型元素,Zn、Pb是铅锌矿区污染较重的元素,而Cr和As是外源叠加较严重的重金属元素。研究区内表层土壤以酸性为主,土壤重金属与pH值没有明显相关性,主要受到污染源强度的影响,以污染源为中心,呈现辐射状递减的分布特征。

Pollution Characteristics of Heavy Metals in Soils in Typical Contaminated Areas, Guizhou Province

Eleven typical contaminated areas with different pollutant sources in the cities of Guiyang, Liupanshui, Duyun and Bijiees in Guizhou Province were selected to study the diversity of pollution characteristics of heavy metals in soils, and supply scientific data to the protection against heavy metal pollution. Cr, Cu, Zn, As, Cd and Pb in 189 soil samples were measured by inductively coupled plasma mass spectrometry (ICP-MS), using cluster analysis and principal component analysis to analyze the results. The results indicated that the comprehensive pollution index of heavy metals in soil was 0.897 in Jinzhongzhen, belonging to the warning degree pollution, and Cd concentration was 0.34 mg/kg in soil, which was affected by phosphorus limestone with a high background value of cadmium. Soils in Erguan Village of Qingyan, Caoguan Village of Baiyun, Jiuan of Huaxi, Houwu of Qingzhen were attacked by heavy-degree heavy metal pollution. Sewage irrigation had an impact on the soil in Wudang of Guiyang, belonging to middle-degree pollution, and the feature element was cadmium. Affected by Pb-Zn smelting and coal mining, soils in Luomo Village of Yemachuan, Anle Village, Xingfu Village and Bagu of Duyun suffered heavy-degree pollution, Due to the presence of independent cadmium deposits in Bagu of Duyun, the single pollution index of Cd was 77.88, and the comprehensive pollution index was 56.22. The results of principal component analysis showed that Cd and Cu were the typical elements with high background values in soils, Zn and Pb were severe contamination elements in Pb-Zn smelting areas, and Cr and As were relatively the overlapped elements from extraneous sources. The surface soil was dominated by acidic soil in all areas, heavy metal contents had no significant correlation with soil pH value, it was basically affected by pollution intensity, cadmium content of soil was almost highest in the center near the pollution sources, and it decreased progressively along the distance from the center.