姜湖贡米产地土壤重金属空间分布、源解析及生态风险评价

Spatial Distribution,Source Apportionment,and Ecological Risk Assessment of Soil Heavy Metals in Jianghugongmi Producing Area,Shandong Province

研究名特优产品土壤重金属分布、来源及其潜在风险对科学管理、安全利用土壤和作物资源具有重要意义.以姜湖贡米产地为研究对象,对名特优产地土壤中的As、Cd、Cr、Cu、Hg、Ni、Pb和Zn进行采样和测定,利用多元统计法进行重金属的相关性讨论,采用ArcGIS 10.2进行重金属空间分布插值分析,利用富集因子法和PMF法对重金属污染进行定量源解析,并进行了潜在生态风险评价.结果表明:(1)研究区土壤重金属As、Cd、Cu、Hg、Pb和Zn含量均低于农用地土壤污染风险管控标准(GB 15618-2018)规定的筛选值,土壤生态环境风险低;Cr和Ni最大值均超风险筛选值,但风险低;研究区pH主要分布范围为6.05~6.69,是适合水稻生长的pH范围.(2)墨河对pH和重金属的空间分布具有指示意义.这与元素的表生地球化学特征息息相关;而Hg和Cd受人为影响显示了不同的空间分布特征,Hg沿河流西侧为中高值分布区,Cd的空间分布南北差异较为显著.(3)基于富集因子法和PMF的定量源解析结果显示,研究区重金属主要来源为耕地农业源、混合源、燃煤源和自然源.各种来源的贡献率分别占24.2%、35.4%、9.5%和30.9%.(4)研究区Hg中强生态风险指数沿墨河西侧分布,而Cd的中度潜在生态风险点集中在墨河两侧耕地中,其他元素潜在生态风险指数(E_(r))均<40.Cd和Hg为研究区主要潜在生态风险元素,而Cd仍是研究区耕地土壤中的主要潜在污染元素.

Taking the Jianghugongmi producing area as the research object,As,Cd,Cr,Cu,Hg,Ni,Pb,and Zn in the soil of the study area were sampled and determined.The correlation of heavy metals was discussed using the multivariate statistical method,the spatial distribution interpolation analysis of heavy metals was carried out using ArcGIS 10.2,the quantitative source analysis of heavy metal pollution was carried out using the enrichment factor(EF) and PMF methods,and the potential ecological risk was evaluated.The results showed that the contents of the soil heavy metals As,Cd,Cu,Hg,Pb,and Zn were lower than the screening values specified in the standard for soil pollution risk control of agricultural land(GB 15618-2018),and the soil ecological environment risk was low;the maximum values of Cr and Ni exceeded the risk screening values,but the risk was low.The main distribution range of pH in the study area was 6.05-6.69,which was suitable for rice growth.The Mohe River indicated the spatial distribution of pH and heavy metals,which was closely related to the supergene geochemical characteristics of the elements.However,Hg and Cd showed different spatial distribution characteristics under human influence.Hg was distributed in the middle and high value distribution area along the west side of the river,and the spatial distribution of Cd was significantly different from north to south.The quantitative source analysis results based on the EF method and PMF showed that the main sources of heavy metals in the study area were agricultural sources,mixed sources,coal sources,and natural sources.The contribution rates of various sources accounted for 24.2%,35.4%,9.5%,and 30.9%,respectively.The medium strong ecological risk points of Hg in the study area were distributed along the west side of the Mohe River,whereas the moderate potential ecological risk points of Cd were concentrated in the cultivated land on both sides of the Mohe River,and the potential ecological risk index(E_(r)) of the other elements was<40.Cd and Hg were the main potential ecological risk elements in the study area,whereas Cd was still the main potential pollution element in the cultivated land soil in the study area.