浙江常山江源石煤矿山周边耕地土壤重金属分布特征与生态风险评价

Distribution Characteristics and Ecological Risk Assessment of Heavy Metals in Cultivated Soil Around Jiangyuan Stone Coal Mine in Changshan, Zhejiang

为系统研究浙江常山何家江源石煤矿山周边耕地土壤重金属分布特征及农产品重金属健康风险,在浙江常山何家江源石煤矿山周边耕地采集了表层土壤、岩石样及水稻、甘蔗两种农产品样品,重点分析了As、Hg、Cr、Cu、Zn、Ni、Cd、Pb、Se等元素含量,采用土壤污染风险筛选值等国家标准,对该研究区土壤重金属污染进行评价,同时对农产品进行As、Hg、Cr、Cu、Zn、Ni、Cd、Pb重金属及Se等元素含量统计。结果表明,石煤矿山周边耕地除Pb含量低于全省土壤背景值外,其它元素均值都高于全省土壤背景值,土壤重金属和硒受地质背景荷塘组黑色岩系控制;除少量清洁外,轻度以上污染样品数占总样品数52%,土壤重金属污染严重。农产品重金属Cd超标严重,其中水稻全部超标、甘蔗50%超标,生态风险较大,但两种农产品富硒率都达50%以上。水稻的生物吸收系数除Hg外,As、Cr、Cu、Zn、Ni、Cd、Pb、Se等元素生物吸收系数普遍高于甘蔗。水稻根系土和稻谷Se、Cd、Ni三种元素都呈正相关,甘蔗根系土和甘蔗中Se、Cd不相关。

To systematically study the distribution characteristics of heavy metals in cultivated soils and the health risks of heavy metals in agricultural products around the Hejiajiang source stone coal mine in Changshan,Zhejiang,samples of surface soil,rice and sugar cane were collected from the cultivated land around the Hejiajiangyuan stone coal mine in Changshan,Zhejiang,and used to analyze the content of As,Hg,Cr,Cu,Zn,Ni,Cd,Pb,Se and other elements.Meanwhile,the national standards such as soil pollution risk screening value were used to evaluate the soil heavy metal pollution in the study area,and the contents of as,Hg,Cr,Cu,Zn,Ni,CD,Pb,heavy metals and Se in agricultural products were counted.The results show that,except for the Pb content of the cultivated land around the stone coal mines,which is lower than the province’s soil background value,the average values of other elements are higher than the province’s soil background value.Soil heavy metals and selenium are controlled by the black rock series of the Hetang Formation in the geological background;except for a small amount of cleanliness,the number of lightly polluted samples accounted for 52%of the total number of samples,and soil heavy metal pollution was serious.The heavy metal Cd of agricultural products exceeds the standard seriously.Among them,all the rice exceeds the standard and 50%of the sugarcane exceeds the standard.The ecological risk is relatively high.However,the selenium enrichment rate of the two agricultural products is more than 50%.In addition to Hg,the bioabsorption coefficients of As,Cr,Cu,Zn,Ni,CD,Pb,Se and other elements in rice are generally higher than those in sugarcane.Rice root soil is positively correlated with Se,Cd and Ni in rice,while sugarcane root soil is not correlated with Se and Cd in sugarcane.