燃煤烟气对土壤-小麦系统中汞累积及分布的影响

为研究燃煤烟气对土壤-小麦系统中汞积累和分布的影响,在小麦苗期和成熟期采集河南省商丘市某燃煤电厂周围农田土壤和小麦植株样品,用ZYG-Ⅱ型智能冷原子荧光测汞仪测量样品中的汞含量。结果表明,小麦苗期和成熟期,土壤样品中汞含量没有超过土壤环境质量标准（GB15618—1995）二级标准的限值。燃煤电厂周围表层土中汞含量要明显高于深层土,呈表层富集现象,苗期小麦根的汞含量高于茎叶,其根、茎叶的汞含量与表层土的汞含量呈显著正相关。小麦从苗期到收获期,表层土、小麦根和茎叶的汞浓度升高。小麦从苗期到收获期,茎叶面积迅速增加,小麦叶片直接从大气中吸收燃煤烟气中的汞,使小麦茎叶通过叶面吸收的汞浓度增加,收获期燃煤电厂周围小麦各器官汞含量为茎叶〉根〉颖壳〉籽粒。成熟期小麦根的汞含量与表层土的汞含量呈显著正相关,而茎叶汞含量与表层土的汞含量无相关性。因此,燃煤烟气中汞沉降影响燃煤电厂周围种植的小麦各器官对汞的吸收和累积。

The Influence of Coal-fired Flue Gas on Accumulation and Distribution of Mercury in Soil-Wheat System

The soil and winter wheat around coal-fired power plant located in Shangqiu City,Henan Province were sampled during the seedling period and the harvest period,and the concentration of mercury was measured with ZYG-Ⅱcold atomic fluorescence spectrometry in order to study the influence of coal-fired flue gas on the accumulation and distribution of mercury in soil-wheat（Triticum aestivum L） system.The results showed that the concentration of mercury in soil during the seedling period and the harvest period didn＇t exceed the limited value of the Soil Environmental Quality Standard in China（GB 15618—1995,Grade II）.Moreover,mercury concentration in the topsoil was higher than that in the subsoil,revealing surface enrichment phenomenon.During the seedling period,the mercury concentration in the wheat roots was higher than that in the stem and leaves,and the concentration in the roots,and stem and leaves showed a significant positive correlation with that in the topsoil.In addition,the mercury content of topsoil,wheat roots,and stem and leaves increased from seedling period to harvest period of wheat.Leaf area of wheat increased rapidly from seedling period to harvest period,and wheat leaves directly absorbed mercury from coal-fired flue gas,resulting in increased mercury concentration by leaf absorption.During the harvest period,the order of mercury content in the winter wheat organs around coal-fired power plant was stem and leaf root glume grain.Furthermore,during harvest period,the mercury concentration in roots had a significant correlation with that in the topsoil,whereas the mercury concentration in stem and leaves had not an apparent correlation with the topsoil.Therefore,mercury deposition of coal-fired flue gas affected the absorption and accumulation of mercury in wheat various organs around coal-fired power plant.