长沙和株洲地区葡萄园土壤重金属含量分析及污染评价

摘要

Sampling the top layer (0~20cm) and the lower layer (20~40 cm)soil from 12 orchards in Changsha and Zhuzhou grape-growing region and testing the levels of lead, cadmium, mercury, arsenic and chromium according to the environmental quality standard for soilsⅡ and environmental quality for producing area of the green food. The experiment was adopted the single factor contaminant index and Nemerow integrated pollution index method to analyze the testing results. The results demonstrate that the heavy metals from the top layer soils were higher than that of the lower layer soil. Pb and As were meet Pollution-free food environmental requirements for producing areas, degree of pollution were Cd>Cr>Hg>As>Pb. 17%integrated pollution index of grape orchard soils were below the permitted level, 50% minor polluted and 33% moderately or Heavily polluted. All grape orchard soils were on and above cordon using the synthetic pollution index. The correlation analysis of heavy metal contents in top layer soils show that the Pb, As and Cr were positively correlated, there are significantly correlation between Pb and Cd, Hg, which suggests that they are highly homologous and may come from the same source of pollution. Grape planted in metal pollution soils took less absorption, all the fruit can meet the national food safety standards, indicating the fact that it can be used as an alternative to the structural adjustment of farmland with slight heavy metal pollution.%通过采样长沙、株洲地区12个观光采摘葡萄园的土壤(0~20 cm和20~40 cm),按照土壤环境质量二级标准和绿色食品产地环境质量标准,用单因子指数法和内梅罗综合污染指数法对土壤重金属铅(Pb)、镉(Cd)、汞(Hg)、砷(As)和铬(Cr)污染的状况进行了评价和影响因子分析.结果表明,0~20 cm土层土壤重金属含量均高于20~40 cm土层土壤;除As、Pb达标外,Cd、Hg和Cr有不同程度污染,重金属元素污染程度依次为Cd>Cr>Hg>As>Pb;有17%的果园综合污染指数<1,达到无公害果园标准,50%的果园达到轻度污染水平,中度和重度果园污染的达到33%;所有的果园重金属综合污染都达到绿色食品土壤警戒线标准及以上;在表层土壤中,重金属元素之间具有正相关关系,其中Pb与As、Cr显著相关,与Cd、Hg呈极显著相关,表明它们之间同源性很高,可能来自同一污染源;葡萄果实对重金属的吸收累积较少,果品均可达到国家食品安全标准,可作为重金属轻度污染农田农业产业结构调整的备选品种.