遵义市植烟土壤中重金属含量及污染评价

Assessment of Soil Heavy Metal Content and Contamination in Flue-cured Tobacco Planting Areas in Zunyi

为了解遵义市植烟土壤中重金属的污染状况,选取遵义市不同县区的表层植烟土壤共24个,测定土壤中Pb,Cd,Hg,As,Cu,Cr,Zn,Ni的重金属元素含量,采用单因子污染指数法和内梅罗（N.L.Nemerow）综合污染指数法研究区域重金属污染情况.结果表明：遵义市5个县区烟草种植土壤中,8种重金属的含量差异不大,仅湄潭县的Cd含量相对较高.各地重金属的含量中,Pb（52.7～27.2 mg/kg）、Cd（0.50～0.18 mg/kg）、Hg（0.12～0.24 mg/kg）、Cr（129.5～70.2 mg/kg）均高于全国土壤背景值,As含量仅遵义县和务川县超过全国土壤背景值,Cu含量除务川县外,均超过全国土壤背景值,Zn、Ni含量除湄潭县外,均高于全国土壤背景值;遵义县、务川县和凤冈县的综合污染指数均低于0.7,处于安全等级,道真县为0.80,湄潭县达0.97,污染等级为警戒级别,而湄潭县接近1.0,有轻度污染的趋势.结论：遵义地区植烟土壤重金属含量处于较低水平,无明显的污染.

In order to study the soil heavy metal contamination situations in flue-cured tobacco planting areas in Zunyi,24soil samples were collected in several counties in Zunyi to detect soil heavy metal content as Pb,Cd,Hg,As,Cu,Cr,Zn,and Ni,and single factor contamination index method and Nemerow integrated contamination index were applied to study the contamination situation in these area.The results showed that there was no difference for the 8heavy metal content except the Cd content in Meitan was relatively higher.The content of heavy metals Pb(52.7~27.2mg/kg),Cd(0.50~0.18mg/kg),Hg(0.12~0.24mg/kg),and Cr(129.5~70.2mg/kg)in all county exceeded nation-wide soil background value,As in Zunyi and Wuchuan Counties exceeded,Cu exceeded except Wuchuan County,Zn and Ni also exceeded background value except Meitan County.The integrated contamination index in Zunyi,Wuchuan,and Fenggang Counties were lower than 0.7in safe level,while in Daozhen County(0.80)reached warning level,but in Meitan County(0.97)close to 1.0,was in warning level and showed trends of mild contamination.Therefore,so far,the soil heavy metal content in flue-cured tobacco planting areas in Zunyi District is still in low level,without obvious contamination.