不同类型土壤-小白菜中Hg转移的主控因素和预测模型

为研究Hg的生物有效性、移动性和转移特征对环境和食品安全的重要性,采集全国18种不同理化性质的土壤,利用温室实验,以小白菜为研究对象,通过添加外源Hg,研究Hg从土壤到小白菜的转移特征,探索影响Hg生物有效性的主要影响因子并建立预测模型。结果表明:不同土壤理化性质、不同浓度Hg处理对小白菜生长表现出多样性,或促进(黄棕壤、黑土、垆土、潮土)、或抑制(灰漠土、湖南水稻土)、或没有显著影响(红壤、砖红壤)。采用逐步多元回归分析并建立了预测模型用于测定小白菜地上可食部分的Hg生物富集因子(BCF)和土壤性质如pH、有机质(OM)、阳离子交换量(CEC)、总氮(TN)、总钾(TK)、铁铝氧化物之间的相关性。预测模型表明:pH和OM是影响Hg从土壤转移到小白菜中两个最关键的因素。

Major controlling factors and prediction models of Hg transfer from different soils to Brassica chinensis

The bioavailability, mobility and transfer characteristics of Hg are critical to the environment and food safety. We conducted a greenhouse study, using Brassica chinensis and 18 soils, to investigate the uptake of Hg by plants and to construct a model for predicting the main factors that influence Hg bioavailability.The results showed that the different soil physical and chemical properties and different concentrations of Hg treatment showed diversity in the growth of Brassica chinensis, or promoted (yellow brown soil, black soil, bauxite, fluvoaquic soil), or inhibited (grey desert soil, Hunan paddy soil), or no significant impact (red soil, brick red soil). A stepwise multiple regression analysis was used to establish a predictive model for the determination of the correlation between Hg bioconcentration factor (BCF) and soil properties such as pH, organic matter (OM), cation exchange capacity (CEC), total nitrogen (TN), total potassium (TK)and ironaluminum oxides. The predictive model shows that pH and OM are the two most important factors that affect the transfer of Hg from soil to Brassica chinensis.