典型矿区周边水田土壤 Cd 生物有效性研究

为遴选可有效表征农田土壤Cd生物有效性的指标,文章采集浙江某地20组稻米及其协同土壤,分析稻米Cd质量比、土壤的基本理化性质、Cd总质量比、不同浸提态Cd质量比及欧共体标准物质局(European Community Bureau of Reference, BCR)形态。结果表明:稻米Cd质量比为0.01~0.51 mg/kg,土壤Cd质量比为0.17~3.15 mg/kg,稻米Cd富集系数为0.04~1.42;土壤Cd主要以弱酸态(40.5%)和还原态(37.1%)存在,二乙烯三胺五乙酸(diethylenetriaminepentaacetic acid, DTPA)浸提土壤Cd能力最强(15.6%);基于 $ \omega(\mathrm{CaCl}_{2}-\mathrm{Cd}) $构建的三次函数建立的回归模型可解释稻米Cd 57.4%方差, $ \omega(\mathrm{CaCl}_{2}-\mathrm{Cd}) $可以作为表征水稻土壤Cd生物有效性的指标,基于水稻土壤Cd生物有效性可提高污染风险评价的科学性。

To select indicators that can effectively characterize the bioavailability of cadmium(Cd) in farmland soil, this paper, based on 20 sets of rice and its synergistic soil from an area in Zhejiang Province, analyzed the Cd content of rice, the basic physical and chemical properties of soil, the total amount of Cd, the Cd content of different extractable states and the European Community Bureau of Reference(BCR) form. The results show that the Cd content of rice is 0.01-0.51 mg/kg, the Cd content of soil is 0.17-3.15 mg/kg, the bioconcentration factor of Cd in rice is 0.04-1.42; the soil Cd is mainly in acid-soluble states (40.5%) and reducible states (37.1%), diethylenetriaminepentaacetic acid(DTPA) has the strongest ability to extract soil Cd (15.6%); the regression model based on the cubic function constructed by $ w(\mathrm{CaCl}_{2}-\mathrm{Cd}) $ can explain 57.4% variance of Cd in rice, hence $ w(\mathrm{CaCl}_{2}-\mathrm{Cd}) $ is preferably chosen as an indicator of Cd bioavailability in rice soil, and research based on the Cd bioavailability in rice soil can make pollution risk assessment more scientific.