摘要
为了给重金属污染农田土壤的安全性评估提供方法学指导,以稻田土壤-水稻体系为对象,通过比较化学提取法(土壤溶液法和0.01 mol·L^(-1)Ca Cl2提取法)和梯度扩散薄膜技术(DGT)所提取的有效态镉(Cd)含量与水稻谷粒中Cd含量(0.06~2.16 mg·kg^(-1))的相关关系,阐述DGT是否能更准确评估Cd的生物有效性及其作用机理。结果表明,土壤Cd全量与谷粒中Cd含量、几种有效态Cd提取量均未显示出显著相关性,不能真实反映Cd的生物有效性。DGT提取的Cd含量与谷粒Cd含量的相关性系数(R_(线性)~2=0.89和R_(曲线)~2=0.94)高于土壤溶液法(R_(线性)~2=0.87和R_(曲线)~2=0.92)和0.01 mol·L^(-1)Ca Cl2提取法(R_(线性)~2=0.80和R_(曲线)~2=0.83),R值分析表明DGT技术模拟了根部吸收土壤Cd过程中土壤固-液释放补给动态过程。因此,与传统化学提取法相比,DGT技术能更好地预测Cd污染土壤(0.31~10.64 mg·kg^(-1))中Cd的生物有效性。
Risk assessment of heavy metal pollution is important in the study of soil environments, though there is no agreed-upon conclu- sion about assessment methods, until now. Assessment methods for the potential risk of cadmium-polluted agricultural soils urgently need to be confirmed. In this study, a soil-flee system was developed to compare the accuracy and feasibility of different methods, including diffu- sive gradients in thin film technology（DGT） and traditional chemical extraction methods. The mechanism of DGT for evaluating Cd bioavail- ability was also discussed. There were significantly positive relationships between Cd concentrations obtained by the three extraction proce- dures and Cd concentrations in rice grain （0.06-2.16 mg· kg-1）. The correlation coefficients obtained by DGT（R =0.89 and R2Curvilinver = 0.94） were much larger than those obtained by the soil solution method （RLinenr=0.87 and RCarviliner=0.92） and 0.01 mol·L-1 CaCl2 extraction method（Rlinear=0.80 and RCarvilinear =0.83 ）. In addition, R values obtained using the 2D D IFS model showed that the solid-liquid dynamic pro- cess was rapid in bulk soils, and R experimental values indicated a sustained supply of cadmium from soil solid to liquid. In general, DGT showed a more scientific prediction of Cd bioavailability in paddy soils with long-range Cd concentrations （0.31 -10.64 mg·kg-1）. If in situ measurement prediction is successful, DGT will be a good prospect in standard settings for evaluating Cd contamination of paddy soils.
作者
刘小莲
杜平
陈娟
任杰
刘继东
韩雷
吴明红
LIU Xiao-lian;DU Ping;CHEN Juan;REN Jie;LIU Ji-dong;HAN Lei;WU Ming-hong(School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China;State Key Laboratory of Environ- mental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China)
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2017年第12期2429-2437,共9页
Journal of Agro-Environment Science
基金
国家自然科学基金项目(41501350)~~
