我国东部地区农田土壤重金属污染概况

Heavy Metal Pollution of Cultivated Soil in Eastern China

随着经济和社会的高速发展,农田土壤重金属污染对粮食安全及人类的身体健康构成巨大威胁。为了解我国东部地区农田土壤重金属的污染现状,基于东部地区农田土壤重金属污染数据,采用半方差函数分析及克里金(Kriging)插值手段,通过内美罗(Nemerow)综合污染指数和地累积指数等土壤重金属评价方法,对我国东部地区农田土壤重金属砷(As)、铬(Cr)、镉(Cd)、汞(Hg)及铅(Pb)的污染概况进行综合分析。结果表明东部地区重金属Hg污染最为严重,均值为中国土壤Hg元素背景值的2.8倍,近30%东部地区处于Hg中度污染水平;其次为Cd,均值为背景值的2倍,50%以上东部地区处于Cd污染警戒线,半方差分析结果显示Cd污染受人类活动影响最强;广东省农田土壤重金属综合污染最为严重,内美罗综合污染指数高达0.854,克里金插值结果显示As、Cd、Hg及Pb的高值区域均在广东省有所分布。

With the rapid development of economy and society,heavy metal contamination of cultivated soil has seriously influenced food security and human health.Based on the data of heavy metal in cultivated soil in eastern China collected from documents,the degree of heavy metal pollution of cultivated land in eastern area was evaluated,by means of semi-variogram analysis,Kriging interpolation,single factor pollution index,Nemerow comprehensive pollution index,and geoaccumulation index.The conclusions showed as follows: the pollution of Pb was the most serious one;the mean value of Hg was 2.8 times higher than background value of element Hg in Chinese soil.Almost30% of eastern area was under the middle pollution level.The pollution of Cd was the second serious one,and results of semi-variogram analysis indicated Cd was the most influenced by human activities.In addition,the mean value of Cd was 2 times higher than the background value of Cd in Chinese soil.Over 50% of eastern area was under the firing line of Cd pollution.Cultivated soil in Guangdong province may be the key region of heavy metal integrated pollution because Nemerow comprehensive pollution index in Guangdong was the highest(0.854)and Kriging interpolation revealed high value area of As,Cd,Hg,Pb distributed in Guangdong province.