典型土地利用方式下土壤重金属污染物分布特征与源解析——以成都平原干溪河流域为例

DISTRIBUTION CHARACTERISTICS AND SOURCE APPORTIONMENT OF HEAVY METALS IN SOILS UNDER TYPICAL LAND USE PATTERNS——A CASE STUDY ON THE GANXI RIVER BASIN OF CHENGDU PLAIN

基于成都平原干溪河流域不同土地利用分区。通过Pearson相关系数分析、内梅罗指数、主成分和聚类分析,探究土壤重金属含量、空间分布、来源及环境风险。结果表明:1)流域表层土壤重金属Pb、Cd、As、Cu、Zn、Ni、Fe均超过土壤背景值,农耕区Cd含量为GB 15618—1995《土壤环境质量标准》二级标准(0.3 mg/kg)1.4倍;农耕区土壤Pb含量(62.56 mg/kg)显著高于工业区(32.25 mg/kg);2)农耕区环境风险相对较高,呈总体轻污染、局部中污染状况;3)全区主成分可分为4种:Fe、Mn、Ti等来源于自然母质,其贡献率为34.9%～37%,其他污染源依次为工业、交通及铅蓄电池迹地或历史手工作坊;4)聚类后,按样点数量划分为32、38、11和2四类,分别受工业及交通、农业面源、交通和背景环境影响。

This paper was based on different land use zonings in the Ganxi River Basin of Chengdu Plain. Pearson correlation, Nemerow index, principal component analysis and cluster analysis were used to explore the contents, spatial distribution, sources and environmental risks of heavy metals in soils. The results showed that: 1) The heavy metals Pb, Cd, As, Cu, Zn, Ni and Fe in surface soil all exceeded the soil background values, and the Cd content in the farming area was 1.4 times that of the GB II Standard(0.3 mg/kg);the soil Pb content(62.56 mg/kg) in farming area was significantly higher than that in industrial area(32.25 mg/kg);2) the environmental risk in farming areas was relatively high, showing overall light pollution and partially moderate pollution;3) there were four principal components in the whole region, including Fe, Mn and Ti, etc. were derived from natural parent materials and their contribution rates were between 34.9% and 37%, while the other sources of pollution were respectively industrial, transport and lead storage battery slashes or historical manual workshops;4) after clustering, the samples were divided into four categories: 32, 38, 11 and 2, which were affected by industrial and transportation, agricultural area source, transportation and background environment, respectively.