【摘要】 通过野外调查和室内分析相结合的方法,研究了河北省安国市中草药种植区土壤重金属As、Hg、Pb、Cd的含量、空间分布特征及草药中重金属含量状况,以及不同中草药对土壤重金属的累积特征,并对种植区土壤和草药重金属污染程度进行了评价.结果表明,种植区土壤重金属As、Hg、Pb、Cd含量均值分别为12.9、0.036、15.6、0.118mg·kg-1,均低于相应《土壤环境质量标准》二级标准值;以土壤背景值为标准评价,单项污染指数评价结果显示,16个中药种植区中土壤As、Hg、Pb、Cd达轻度污染的比例分别为18.75%、43.75%、0%、100%,且6.25%的种植区土壤Hg污染达到中度水平.综合污染指数评价结果表明,12.5%种植区土壤重金属污染等级为警戒级,其余各地区均处于轻度污染水平;而以《土壤环境质量标准》二级标准值评价,各种植区单项污染指数及综合污染指数结果均<0.7,土壤环境清洁;绝大多数(>95%)种植区草药样品污染指数<1,不同中草药对土壤重金属的累积能力存在明显差异:紫菀、知母对Cd的富集系数及白芷、北沙参对Hg富集系数均>1.因此,在中药GAP(优良农业生产)基地土壤质量评价过程中,应重视中草药自身特性对重金属吸收和累积的影响.更多还原

【Abstract】 Concentrations of As,Hg,Pb,Cd in soils and herbal medicine samples from cultivated regions of Anguo City in Hebei Province were analyzed and assessed,and the bioconcentration factors of different herbal medicines were studied and discussed as well.The results showed that the average contents of As,Hg,Pb,Cd in soils from herbal medicine cultivated regions were 12.9,0.036,15.6,0.118 mg·kg-1,respectively.Concentrations of heavy metals in soils were lower than classⅡof the soil environmental quality standard.When local soil background values of heavy metals were used as assessment standard,among the 16 cultivated regions the percentage of As,Hg,Pb,Cd belonging to lightly pollution class were 18.75%,43.75%,0%,100%,respectively based on the single pollution index.And the Nemerow index results were between 1 and 2,which suggested the soils were at slight pollution level.However,when quality standard class Ⅱ was used,both the single pollution index and Nemerow index did not exceed 0.7,which means that soils investigated were generally safe for cultivation of Chinese herbal medicines.The assessment of heavy metals in herbal medicines showed that the pollution indices of most herbal samples(< 95%) were lower then 1.Cd bioconcentration factors of Aster tataricus L.and Anemarrhena asphodeloides Bunge,Hg bioconcentration factors of Angelica dahurica(Fisch.ex Hoffm.) Benth.et Hook.f.and Glehnia littoralis F.Schmidt ex Miq.were above 1.Therefore,the accumulation characteristic of heavy metals in Chinese herbal medicines should be fully concerned when GAP base soil quality assessment was taken.更多还原