摘要
老化过程对土壤重金属有效性和毒性起着关键性作用.由于我国土壤类型的复杂性,目前对于我国土壤中铬(Cr)的老化过程、转变速率及影响Cr在土壤中老化的关键因子仍然不清楚.本研究选取了全国22种典型土壤,使用0.01 mol.L-1CaCl2作为有效态提取剂,研究我国典型土壤中外源Cr(Ⅲ)的老化过程及影响因子,为准确评价重金属污染的生态环境风险提供科学依据.结果表明,有效态Cr含量随时间先是快速下降,然后缓慢持续降低.在培养期间的前21 d下降速率快,而以后则变化比较缓慢.Elovich方程可以有效拟合有效态Cr在我国22种典型土壤中转化的动力学过程,方程的斜率参数可以作为Cr在土壤中老化速率的表征参数,并用它来比较不同土壤中Cr的老化速率快慢.老化速率与土壤性质的逐步回归分析结果表明,土壤性质中对老化速率影响最大的是有机质,其次是pH和活性氧化铁.
Aging process is a key factor influencing the availability and toxicity of heavy metals in soil.However,the aging of chromium（Cr） in soils and its influence factors are still unclear,as a result of complexity of soils in China.This study was conducted to investigate the aging process of Cr（Ⅲ） in 22 typical soils of China by using 0.01 mol·L-1CaCl2 as the extractant for available Cr.The results manifested that Cr spiked in the soil was time-dependently transferred from the available fraction into less labile fractions.Two regions could be distinguished： the first one for short extraction time（t21 days）,corresponding to a faster transformation of metals and the second for longer extraction time（t 21 days） where the transformation was relatively slower.The decrease of Cr in available fraction during the incubation could be simulated by the Elovich equation,and decrease rates were applied to reflect the transformation rates of aging process among various soils.Multiple regression analysis showed that decrease rates might be related to the organic matter,pH and amorphous Fe oxides of soil,and organic matter was the key factor to the aging process.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2013年第2期698-704,共7页
Environmental Science
基金
公益性行业(农业)科研专项(200903015)
关键词
铬
典型土壤
老化
动力学过程
影响因子
chromium
typical soils
aging process
kinetic equation
influence factor
