广西贵港柑桔产区土壤重金属污染及生态风险评价

Soil Heavy Metals Pollution and Ecological Risk Assessment in Citrus Production Areas of Guigang,Guangxi Province

以广西贵港柑桔产区土壤为研究对象,分析了土壤中As、Hg、Cd、Cr、Cu、Sc、Pb、Zn 8种重金属含量及污染特征,基于农用地土壤污染评价标准(GB15618-2018),利用潜在生态危害指数法评价了该产区重金属的综合潜在生态风险。结果表明:Cr、Ni、Cu、Zn、As、Hg、Pb 7种元素含量均值低于土壤污染风险筛选值,Cd元素含量均值(1.22mg/kg)高于风险筛选值(0.3mg/kg)。Pb、Zn元素与Hg、Ni元素各自具有相似的空间分布规律,Cd元素含量有从中心向四周扩散的趋势。Cd元素处于较强的风险水平,很强与极强级别样本所占比例分别为17.5%和45%。Hg元素中度、强风险级别占比分别为39.5%、29.5%,说明该研究区土壤中Cd、Hg元素污染较严重。综合潜在风险指数RI均值为342.4,属于强生态风险,主要受Cd、Hg元素污染影响。

To characterize the pollution and potential ecological risk from heavy meals in soil of farmland in Guigang County,The content and pollution characteristics of eight heavy metals(As,Hg,Cd,Cr,Cu,Sc,Pb and Zn) in the soil of Citrus producing area in Guigang,Guangxi were analyzed.Based on the Soil Environmental Quality Risk Control Standards for Soil Contamination of Agricultural Land(GB15618-2018),The comprehensive potential ecological risk of heavy metals in this area were evaluated by the potential ecological hazard index method.The results showed that the concentrations(mea valve) of Cr,Ni,Cu,Zn,As,Hg and Pb were lower than the soil pollution risk screening values(RSV) among all the soil heavy metals in the study region.The average content of Cd(1.22 mg/kg) is higher than the risk screening value(0.3 mg/kg).The elements of Pb and Zn have a similar spatial distribution laws with Hg and Ni,Cd element concentration has a tendency which spread from heart to surrounding.Cd concentration was higher than RSV,it was at a strong risk level,the proportion of strong and very strong samples were 17.5% and 45%,respectively.The proportion of moderate and strong risk levels of Hg were 39.5 % and 29.5 %, respectively, which indicated that the Cd and Hg contamination in the research area was more serious.Furthermore,The average of the potential risk index(RI) is 342.4 in this area,which indicates a high level of potential risk,mainly due to the high levels of Cd and Hg contamination.