桂林市菜地土壤-蔬菜汞污染研究和评价

对桂林市近郊8个不同片区蔬菜产地的118个土壤样品和71个蔬菜样品中汞的含量水平进行了调查和分析。运用单因子污染指数法评价了菜地土壤一蔬菜中汞的污染现状。研究表明，桂林市及近郊菜地土壤和蔬菜已受到不同程度的汞污染，全市各片区菜地土壤汞含量平均值为0．098-0．523mg／kg，以国家土壤环境质量标准二级标准评价，土壤平均污染指数在0．33-1．74范围内，属非污染或轻污染状态，除穿山南片和纸马铺外，其余采样点均有样本超过国家二级标准，其中七星公园东北片的土壤汞超标率较高，达71．4％，污染情况比较均一；虞山桥东南岸土壤汞超标率较低，为33．3％，但土壤汞含量变异较大，说明污染情况变化大。全市各片区老菜的汞含量平均值为0．0625-0．128mg／kg，为国家标准GB2762—1994规定蔬菜汞含量(0．01mg／kg)的6．25—12．8倍，超标率已达100％。实验还发现，蔬菜中的汞含量与土壤中的汞含量具有显著的相关性，且蔬菜汞的大部分分布于地上部可食部分。分析了菜地土壤汞污染的主要原因，可能与使用含汞农药和生活垃圾肥有关。

Investigation and assessment on mercury pollution in soils and vegetables of Guilin

Mercury pollution in Guilin city and its suburb area was investigated with 118 soil samples and 71 vegetable samples. The results indicated that the soils and vegetables in studied are polluted with different extent of Hg, thereinto, the northeast region around Sevenstar Park is the most seriously contaminative area, the southeast region around Yusan bridge has lower Hg content but with a high variability. The average content of Hg in soils and vegetables are 0.098~0.523 mg/kg and 0.062 5~0.128 mg/kg respec- tively, the pollution indexes for Hg are 0.33~1.74 and 6.25~12.8, according to the soil environmental quality standard(GB 15168-1995)and the farm product quality standard(GB 2762-1994)of China . It is found that there is a correlation between the content of Hg in vegetables and that in soils, and a majority of assimilated Hg in vegetables is distributed in the up-ground edible parts. Analyses of soil pollution show that it is mainly associated with application of pesticides with Hg and garbage fertilizer.