摘要
为了探究巯基化坡缕石作为钝化剂在镉污染碱性土壤上的适用性及应用潜力,选取典型镉污染碱性土壤,以青菜和生菜为模式作物开展盆栽试验和土壤培养试验,研究巯基化坡缕石对碱性土壤镉污染的快速钝化修复效应。结果表明:巯基化坡缕石在应用剂量为0.1%~0.3%(m/m)时可以使生育期内青菜地上部镉含量降低81.44%~93.44%,根系镉含量降低68.47%~85.63%,生菜地上部镉含量降低65.11%~92.18%,根系镉含量降低57.77%~91.92%。收获时可食部位镉含量满足国家食品卫生标准限量值要求,在极低的应用剂量下显著的钝化效应是其优势。巯基化坡缕石可使土壤DTPA浸提有效态镉含量降低68.57%~84.10%,钝化过程速度快,5 d左右达到平衡,可以用二级动力学拟合。连续浸提形态分析显示,巯基化坡缕石能够快速减少土壤中可交换态和碳酸盐结合态镉含量,并显著提高易还原金属氧化物结合态镉含量,使镉由活泼态向不活泼态转化,从而减少作物吸收累积。巯基化坡缕石同时抑制了青菜和生菜对镉的转运系数和生物累积系数,进一步降低了可食部位镉含量。研究表明巯基化坡缕石是一种在镉污染碱性土壤上具有快速钝化作用和良好应用潜力的高效钝化剂。
To investigate the applicability and potential of thiolated palygorskite as an immobilization amendment for Cd-contaminated alkaline soil,pot experiments were conducted with pak choi and lettuce as model plants cultivated in Cd-contaminated alkaline soil.These tests were combined with soil incubation experiments were conducted to investigate the rapid immobilization effect of thiolated palygorskite on the Cd in alkaline soil.Results showed that applications of thiolated palygorskite at dosages of 0.1%~0.3%could reduce Cd concentration by 81.44%~93.44%and 68.47%~85.63%,respectively,in the shoots and roots of pakchoi during its growth period.The Cd concentrations in the shoots and roots of lettuce decreased by 65.11%~92.18%and 57.77%~91.92%,respectively.The Cd concentration in the edible parts of the mature plants satisfied the maximum permitted level of the national standard,with another great advantage of thiolated palygorskite being a significant immobilization effect even at trace application dosages.Thiolated palygorskite can reduce DTPA(diethylene triamine pentaacetic acid)extractable Cd concentrations in the soil by 68.57%~84.10%in a rapid immobilization process that reached equilibrium at approximately 5 d;this could be fitted with second-order kinetics.Sequential extraction analysis showed that thiolated palygorskite quickly reduced the concentrations of exchangeable and carbonate-bound Cd in alkaline soil and significantly increased the concentrations of the easily reducible metal oxide-bound Cd,thereby promoting the transformation of Cd from active species to non-active fractions and thus reducing its accumulation in the edible parts of plants.Thiolated palygorskite also simultaneously inhibited Cd transport factor and biological accumulation coefficient in both pakchoi and lettuce.This study thus confirms that thiolated palygorskite is an efficient immobilization amendment with a good potential for application in Cd-contaminated alkaline soil.
作者
何丽质
徐应明
宋常志
吴义茜
黄青青
梁学峰
HE Li-zhi;XU Ying-ming;SONG Chang-zhi;WU Yi-qian;HUANG Qing-qing;LIANG Xue-feng(Key Laboratory of Original Environmental Pollution Control of MARA,Agro-Environmental Protection Institute,Ministry of Agriculture and Rural Affairs,Tianjin 300191,China;School of Engineering and Technique,Tianjin Agricultural University,Tianjin 300384,China)
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2021年第2期319-328,共10页
Journal of Agro-Environment Science
基金
中国农业科学院科技创新工程项目(CAAS-CXGC-xym-2018)
国家现代农业产业技术体系项目(CARS-03)
国家重点研发计划项目(2018YFD0800705)。
关键词
镉
钝化
巯基化坡缕石
碱性土壤
青菜
生菜
cadmium
immobilization
thiolated palygorskite
alkaline soil
pakchoi
lettuce
