土壤重金属Pb和Cd在蕹菜中的累积特征及产地环境安全临界值

Soil Pb and Cd Accumulative Characteristics in Swamp Cabbage(Ipomoea aquatica Forsk.)and Their Environmental Critical Values in Production Area for Food Security

通过盆栽方法研究了水稻土和潮土两种土壤条件下蕹菜对Pb和Cd的累积特征,并探讨了Pb与Cd在产地土壤环境中的安全临界值。结果表明:两种土壤中蕹菜的Pb和Cd累积量与土壤Pb、Cd添加量均呈正相关关系,茎中的累积量显著高于叶。水稻土和潮土环境下,蕹菜茎中的Pb平均含量分别是叶中的3.86、2.02倍,Cd平均含量分别是叶中的3.58、4.73倍;在同一处理水平下,水稻土中Pb和Cd比潮土中更易被植株累积,水稻土环境下蕹菜茎、叶中Pb含量分别是潮土环境下的4.88、2.56倍,Cd含量则分别是潮土环境下的3.04、4.02倍;依据国家食品污染物限量标准(GB2762—2005)进行方程拟合,得出种植蕹菜的水稻土中Pb的安全临界值为57.83mg·kg-1,潮土中Pb和Cd的安全临界值分别为77.02、0.47mg·kg-1,均高于国家土壤环境安全标准限制的临界值(HJ332—2006)。

Plumbum（Pb）,cadmium（Cd）accumulative characteristics in swamp cabbage（Ipomoea aquatica Forsk.）under 2 types of soils（paddy and alluvial soils）were studied by potted experiment,and their environmental critical values for food security in its production area were also discussed.The results showed that： the accumulative amounts of Pb and Cd in swamp cabbage were correlated with added amount of Pb and Cd in soil.The accumulative amounts in stem were much higher than those in leaf.Under paddy and alluvial soil comdition,the average levels of Pb in stem were 3.86 and 2.02 times of those in leaf,and the average levels of Cd in stem were 3.58 and 4.73 times of those in leaf,respectively.Under same treatment level,Pb and Cd in paddy soil were easily accumulated by crop than in alluvial soil.In paddy soil,the Pb and Cd contents in leaf of swamp cabbage were 4.88 and 2.56 times of those in alluvial soil,and Cd contents were 3.04 and 4.02 times of those in alluvial soil,respectively.according to national standards for maximum contamination level in food（GB 2762—2005）,the environmental critical values of soil Pb in paddy field was 57.83 mg·kg^-1,and the environmental critical values of soil Pb and Cd in alluvial field were 77.02 mg·kg^-1 and 0.47 mg·kg^-1,respectively for safe swamp cabbage growing.These critical values were both significantly higher than those in the national standards for soil security（HJ 332—2006）.