长沙“百里茶廊”茶园土壤重金属含量及环境质量特征

采用野外调查采样和室内分析方法测定了长沙"百里茶廊"茶叶基地土壤重金属含量,研究了其分布特征及变化规律,并用污染指数方法评价了其土壤环境质量.结果表明,土壤全铅、全汞、全镉、全铬、全砷和全镍含量值基本在土壤背景值范围内,平均含量值分别为42.7、0.068、0.074、92.2、12.4和19.5 mg/kg.均低于无公害茶叶产地环境条件标准(NY 5020-2001)所要求的最低值.根据国家<土壤环境质量标准>,长沙"百里茶廊"茶叶基地的土壤环境质量全部符合国家二级标准.且汞、镉、镍元素的含量达到国家一级标准.除湘丰茶场土壤铬的单项污染指数为0.837,处于警戒级别土壤质量尚清洁外,其它5种重金属的单项污染指数均小于0.7,处于安全级别土壤清洁无污染.6个茶叶基地的综合污染指数均小于0.7.表明长沙"百里茶廊"茶叶基地的土壤环境质量总体达到安全级别土壤清洁无污染.适合无公害茶叶基地的建设.

Content of Soil Heavy Metals and Characteristics of Environmental Quality in Tea Plantations of Changsha Baili Tea Zone

Abstract: The distributing and changing characteristics and content of soil heavy metals was studied using methods of field survey and sampling, indoor analysis, and pollution index was used to investigate the soil environmental quality in the tea plantations of Changsha Baili Tea Zone. The results showed that the content of soil total Pb, Hg, Cd, Cr, As, Ni basically was in the soil background value, their averages were 42.7, 0.068, 0.074, 92.2, 12.4 and 19.5 mg/kg respectively. The content of heavy metals was lower than the standard of Environmental Qualification of Nuisance Free Tea Producing Area (NY5020-2001). Simultaneity, soil environmental quality in tea plantations of Baili Tea Zone, it answered for the second grade of State Environmental Quality Standard for Soils in PRC (GB15618-1995), achieved safe glass, and the content of soil Hg, Cd, Ni accorded to the first grade of GB15618-1995, these results showed the Changsha Baili Tea Zone were propitious to develop nuisance free tea production. Besides the single pollution index of Cr was 0.837 and in warning class at the tea plantation of Xiangfeng, the others were all less than 0.7, and in the safe class. The integrated index of 6 tea bases was all less than 0.7, in the safe class, the soil environmental quality was cleanness on the whole at Changsha Baili Tea Zone, and the soils were suitable for non-polluted agricultural production.