闽中某矿区县茶园土壤和茶叶重金属含量及健康风险

以闽中某矿区县茶园表层土壤（0~20cm）为研究对象，采集了25份茶园土壤样品，分析了土壤中重金属Cr、Ni、Cu、Zn、As、Pb、Cd和Co的含量，分别利用地累积指数法和潜在生态风险指数法对土壤重金属的污染现状和潜在生态风险程度进行评价；同时收集矿区茶叶企业23个商品茶样品，利用美国国家环保署（USEPA）推荐的健康风险评价模型进行人体重金属健康风险评价.结果表明：（1）矿区茶园表层土壤Cr、Ni、Cu、Zn、As、Pb、Cd和Co平均含量分别为110、23.5、23.0、107、50.7、78.0、0.23和14.3mg/kg，均明显高于福建省土壤背景值；（2）茶园土壤地累积指数（I_geo）表现为As > Cd > Cr > Pb > Zn > Co > Ni > Cu，As属于重度污染，Cd和Cr属于中度污染，其它5种重金属元素污染风险较低；（3）单项潜在生态风险系数（E）的大小顺序依次为Cd > As > Pb > Co > Ni > Cr > Cu > Zn，土壤Cd属于很强生态风险，土壤As属于较强生态风险，其余属于轻微生态风险.8种重金属综合潜在生态风险指数（RI）平均值为255.74，属于较强风险级别，Cd和As是最主要的潜在生态风险因子.（4）商品茶中重金属Cr和Cd含量均低于限量标准，个别茶样中Cu、As和Pb含量超标，说明茶叶中重金属含量总体处于安全级别；（5）健康风险评价结果表明，茶叶中重金属元素健康个人年风险总和为1.01×10^-4~9.07×10^-5，乌龙茶的个人年风险总和稍高于美国环境保护署（USEPA）推荐的最大可接受风险水平（1.0×10^-4），红茶和绿茶低于USEPA推荐的最大可接受风险水平；茶叶中重金属元素健康风险以Cr为主，平均贡献率为90.38%，是主要的风险元素，其余重金属元素处于安全范围之内.

Concentrations and health risk assessment of heavy metals in tea garden soil and tea-leaf from a mine county in central Fujian province

To investigate the concentrations and health risk assessments of heavy metals in tea garden soils and tea-leaf,25topsoil (0~20cm) and 23 commercial tea samples were collected from a mine county in central Fujian province.The concentrations of 8heavy metals (Cr,Ni,Cu,Zn,As,Pb,Cd and Co) in topsoil were analyzed,and the potential ecological risk degree of heavy metals were comprehensively evaluated with the methods of geoaccumulation index (I_geo) and potential ecological risk idex (RI).The preliminary health risk assessments of these eight heavy metals in the commercial tea were evaluated with the USEPA health risk assessment model.The results showed that:(1) the average contents of Cr,Ni,Cu,Zn,As,Pb,Cd and Co were 110,23.5,23.0,107,50.7,78.0,0.23 and 14.3mg/kg in the topsoil,respectively,which were all higher than the background value in the soil in Fujian.(2) The order of I_geo was As > Cd > Cr > Pb > Zn > Co > Ni > Cu,with heavy pollution for As,medium pollution for Cd and Cr and low comtaminated risk for the other metals,respectively.(3) The order of potential risk for each element was Cd > As > Pb > Co > Ni > Cr > Cu > Zn,with Cd of higher and As of high ecological risk,and with slight ecological risk for the other heavy metals The average RI of 255.74 was a higher level,which was mainly attributed to Cd and As.(4) The contents of Cr and Cd of commercial tea samples were within the limits of corresponding quality standard,and Cu,As and Pb-abnormal only occurs in few commercial tea samples,indicating that the overall level of heavy metal in commercial tea were security level.(5) Health risk assessment results of commercial tea indicated that heavy metals of personal total annual risk was 1.01×10^-4 to 9.07×10^-5.The personal total annual risk of oolong tea was slightly higher while black and green tea were lower than the maximum acceptable levels recommended by US EPA (1.0×10^-4).The contribution rate of 90.38% for Cr was the highest health risk factor for all the 8dectected heavy metals,with the other metals within the security range.