成都平原农田土壤Pb的形态特征及其生物效应研究

在成都平原农田土壤和作物中Pb含量分析的基础上,研究了土壤Pb形态分布特征及其影响因素,以及不同形态Pb对水稻、小麦、油菜籽Pb累积的影响。结果表明:成都平原土壤Pb活性形态(可交换态、碳酸盐结合态、铁锰氧化物结合态、有机结合态)含量相对较高,占总量的40%以上,其含量主要受土壤pH、有机质的影响。作物Pb含量以小麦籽粒最高,稻谷其次,油菜籽最低,对Pb的富集能力为:水稻>小麦>油菜。稻谷与小麦Pb含量主要受土壤有机结合态Pb含量的影响,而油菜籽Pb含量与土壤可交换态和碳酸盐结合态Pb含量间呈显著正相关。

Speciation and Bioavailability of Pb in Farmland Soils in Chengdu Plain

Based on the analysis of the content of Pb in the crop and farmland soils in Chengdu plain, the speciation characteristics and its affecting factors of Pb in soils, and the effect of different Pb speciation on the accumulation of Pb in rice, wheat and rapeseed were studied, respectively. The results showed that the content of the labile fractions (exchangeable, carbonate combined, Fe-Mn oxides combined, organic combined) was higher and amounted to 40% of the total, and mainly affected by the soil pH and soil organic matters. The order of the content of Pb in crops was as follows: wheat seeds >rice seeds >rapeseed, whereas the order of the enrichment coefficient for Pb was as follows: rice >wheat> rapeseed. The content of Pb in rice and wheat was mainly affected by Pb bounded to organic matter in the soils, whereas the content of Pb in rapeseed was significantly correlated to both exchangeable and bound to carbonate speciations in the soils.