海南岛农田土壤重金属污染的评价及其来源分析

对海南岛的农田土壤进行了系统的采样分析,共采集311个样品,分析了其中的Cd,Cr,Pb,As和Hg 5种重金属的质量含量,同时利用GIS技术和多元统计相结合的方法,研究了上述5种重金属元素的空间分布特征和来源.重金属元素Hg,Cd,Cr,Pb和As的质量含量平均值均低于国家(GB15618-1995)Ⅱ级标准,Hg的质量含量最高值为1.63 mg·kg-1,Cd的最高值为0.64 mg·kg-1,Cr的最高值达586.70 mg·kg-1,均超过国家土壤环境质量的Ⅱ级标准,5种重金属元素中只有As元素的平均值低于研究区背景值,土壤中重金属呈明显积聚的趋势.5种重金属元素的来源分析表明,5种元素反映了3个主因子,因子1为"自然源因子",主要包括Hg,Cr和Pb元素,其质量含量与对应元素背景值相当;因子2为"工业及交通源因子",主要是Cd元素;As元素在因子3中,其高值区主要位于东方市、三亚市、琼中县等地区.海南岛农田土壤重金属元素质量含量总体较好,土壤重金属元素Cd,Cr,Pb和Hg不仅有外源,且发生了一定程度的积累,它们是该地区土壤主要的环境隐患.

Pollution Evaluation and Preliminary Analysis of Pollution Sources of Heavy Metals in Agricultural Soil of Hainan Island

The objective of this study was to assess the situation and major sources of the heavy metal contamination of arable soils in Hainan Island.311 samples of arable soils in Hainan Island were taken using systematic sampling analysis.Heavy metal contents of Cd,Cr,Pb,As and Hg in the soil were determined.Combining Geographical Information System （GIS） with multivariate statistical analysis,the spatial distribution pattern and major sources of the five elements were studied.The results showed that the average concentrations of Hg,Cd,Cr,Pb and As were all below the Grade Ⅱ standard of National Environmental Quality Standard for Soil （GB15618-1995）.However,the maximum values of Hg,Cd and Cr exceeded the soil environmental quality standard,being 1.63,0.64 and 586.70 mg · kg-1,respectively.Especially,the total concentrations of Hg,Cd,Cr and Pb all exceeded the soil background content of Hainan Island.The results of factor analysis grouped Hg,Cr,and Pb in Factor 1,Cd in Factor 2,and As in Factor 3.Factor 1 was mainly affected by the soil back-ground.Factor 2 was mainly affected by industries.The As element in factor 3,of which the high value was mainly distributed in Dongfang,Sanya and Qiongzhong City.The contents of heavy metals in agricultural land in Hainan Island are in good conditions.However,not only there are external Cd,Cr,Pb and Hg,but also there are accumulated Cd,Cr,Pb and Hg,which will result in potential environmental problems.