摘要
以培养试验模拟3种水分条件(80%田间持水量、干湿交替及淹水)下,重金属铅(Pb)在紫色土中形态转化的动态过程,结果表明,外源Pb进入紫色土后,随着培养时间的增长由交换态向碳酸盐态、铁锰氧化物态、有机结合态转变,残渣态所占比例基本稳定.Elovich方程可以拟合交换态Pb在紫色土中转化的动力学过程.交换态Pb在土壤中的下降速率可以作为Pb形态转变率的表征参数,并用它来比较不同水分条件下Pb在紫色土中形态转变速率的快慢.3种水分管理模式下,Pb在紫色土中交换态转变速率的顺序是:淹水>干湿交替>80%田间持水量.水分条件会改变紫色土pH、Eh及无定形氧化铁含量,并增加有机质复合体和碳酸盐对交换态Pb的吸附能力,从而间接影响外源Pb在紫色土中的形态转化及分布.
This study deals with solid-phase redistribution of moisture regimes （80% field capacity, wetting-drying added lead （Pb） in purple soil incubated under three cycle, and flooding）. Pb spiked in the soil transformed from the easily extractable fraction （the exchangeable fraction） into less labile fractions （carbonate-, Fe-Mn oxide- and the organic matter-bound fractions）, in a time-dependent manner. Mobility of the metal was thus reduced. No significant change was found for the residual fraction of Pb in the soil during the whole incubation. The decrease of Pb in exchangeable fraction during the incubation could be simulated by Elovich equation, and its decrease rate reflects the transformation rate of metal speciation among various moisture treatments. The transformation rate of Pb in purple soil generally followed the order： flooding 〉 wetting-drying cycle 〉 80% field capacity. This might be related to the change in pH, Eh and carbonate, organic matter- complex and concentration of amorphous Fe oxides under submerged condition.
出处
《环境化学》
CAS
CSCD
北大核心
2011年第12期2080-2085,共6页
Environmental Chemistry
基金
中央级公益性科研院所基本科研业务费专项(农业部环境保护科研监测所)资助
关键词
水分
铅
形态
紫色土
moisture regime, lead, fractionation, purple soil.
