山东省露地蔬菜产地土壤重金属含量的环境质量分析与评价

Analysis and Evaluation of Soil Heavy Metal Environmental Quality in Farmlands of Vegetables Cultivated in Open Field of Shandong Province,China

对山东省露地蔬菜产地的土壤进行了重金属Cd、Hg、As、Pb、Cr、Cu、Zn和Ni含量的抽样调查分析,并采用单项质量指数与综合质量指数相结合的方法对重金属的环境质量状况进行了评价。结果表明,莱阳露地蔬菜产地、金乡大蒜、章丘大葱产地土壤各重金属的平均含量均低于"食用农产品产地环境质量评价标准"(HJ332—2006)规定的限值,三地土壤重金属的单项质量指数均≤0.7,综合质量指数分别为0.56、0.50和0.43,土壤环境质量均为1级,属于清洁水平,适宜发展无公害蔬菜。同时发现,部分地区有重金属含量超标现象,莱阳Cu的样本超标率为13.64%,金乡Cd、Cu和Hg的样本超标率分别为5.41%、5.41%和2.70%,章丘Ni的超标率为4.76%。重金属含量之间多呈正相关关系,其中Cd与Zn,Cu与Zn,Pb与Cr之间的相关性达到极显著水平(P<0.01),As与Ni,Ni与Zn,Zn与Pb,Pb与Cu,Cu与Cr之间的相关性达到显著水平(P<0.05)。大部分监测点的重金属含量均高于山东农业土壤自然背景值,表明在监测点土壤中产生了重金属累积。对山东省其他露地蔬菜产区土壤的随机调查,没有发现重金属含量超标。

Soil heavy metals contents,Cd,Hg,As,Pb,Cr,Cu,Zn and Ni,in farmlands of vegetables cultivated in open field of Shandong Province were investigated by randomly sampling.The environmental quality conditions of these heavy metals were evaluated by methods of single quality index and complex quality index.Results showed that the average contents of heavy metals in vegetable soils of Laiyang,garlic soils of Jinxiang and scallion soils of Zhangqiu were all under the limit values prescribed by＂Farmland environmental quality evaluation standards for edible agricultural products（HJ 332—2006）＂.The heavy metal contents varied greatly among different sites.The coefficients of variation（C.V.）of the studied eight heavy metals were among 10 % and 60% in Laiyang,among 20% and 120% in Jinxiang,and among 12% and 51% in Zhangqiu.The single quality indices of the eight elements in the studied three places were all lower than or equal to 0.7.The comprehensive quality index of the eight elements was 0.56 in Laiyang,0.50 in Jinxiang,and 0.43 in Zhangqiu.The soil environmental quality in the studied three places were all set at the first class belonging to clean level and were fit for the plantation of no pollution vegetables.But the contents of heavy metals in some areas were beyond the limit values,and the beyond rate of Cu in Laiyang was 13.64 %,the beyond rate of Cd,Cu and Hg in Jinxiang was 5.41%,5.41% and 2.70% respectively,the beyond rate of Ni in Zhangqiu was 4.76%.Most of the heavy metals were positively correlated in contents,and the correlation of Cd and Zn,Cu and Zn,Pb and Cr reached a very significant level（P0.01）,while the correlation of As and Ni,Ni and Zn,Zn and Pb,Pb and Cu,Cu and Cr reached a significant level（P0.05）.Contents of most of the tested heavy metals were higher than natural background value of agricultural soils in Shandong Province,which indicated that metals were accumulated in the studied soils.Compared with the natural background values,the soil Cu content in Laiyang increased nearly 2 times,and the soil Hg content increased nearly 4 and 3 times in Jinxiang and Zhangqiu respectively.Investigation on other farmlands of vegetables cultivated in open field of Shandong Province showed that the soils were not contaminated by heavy metals.