外源Pb在三种典型土壤中老化过程差异性研究  

Differences in the aging of added lead in three typical soils

作　　者：孙硕 李菊梅[1] 马义兵[1] 赵会薇 SUN Shuo;LI Ju-mei;MA Yi-bing;ZHAO Hui-wei(Institute of Agriculture Resources and Regional Planning,Chinese Academy of Agricultural Sciences,Beijing 100081,China;The Semi-arid Agriculture Engineering & Technology Research Center,Shijiazhuang 050051,China)

机构地区：[1]中国农业科学院农业资源与农业区划研究所,北京100081 [2]国家半干旱农业工程技术研究中心,石家庄050051

出　　处：《农业环境科学学报》2019年第8期1936-1945,共10页Journal of Agro-Environment Science

基　　金：国家重点研发计划项目(2016YFD0800400);国家科技支撑计划项目(2015BAD05B01)~~

摘　　要：为探究外源Pb在不同土壤中的老化过程,对外源添加Pb的土壤进行不同时间(1、3、9、30、100、360 d)的室内培养,并利用三种化学提取剂(0.01 mol·L^-1CaCl2、0.05 mol·L^-1EDTA-2Na和0.43 mol·L^-1HNO3)表征的有效态Pb的动态变化,研究了我国三种典型土壤(红壤、黑土和潮土)中有效态Pb的老化过程。结果表明,有效态Pb提取率受不同提取剂和土壤性质的显著影响,0.43mol·L^-1HNO3(81%~99%)和0.05 mol·L^-1EDTA-2Na(66%~99%)对Pb的提取率远高于0.01 mol·L^-1CaCl2(0.002%~13.8%),红壤中0.01 mol·L^-1CaCl2提取率(7.2%~13.8%)远高于潮土和黑土(0.002%~0.037%)。三种土壤中0.05 mol·L^-1EDTA-2Na提取率排序为:黑土>红壤>潮土;三种土壤中0.43 mol·L^-1HNO3提取率较高且随老化时间无显著变化,而0.01 mol·L^-1CaCl2提取态Pb总体上均随老化时间显著降低后逐渐变缓。红壤和潮土中0.05 mol·L^-1EDTA提取态Pb的老化过程经过30 d的快速下降后逐渐变缓,到100~360 d后基本达到平衡,而黑土中变化相对缓慢。三种土壤适宜的老化时间分别为:100 d(红壤)、360 d(潮土)、>360 d(黑土)。外源Pb在三种土壤中的老化过程符合一阶指数衰减方程。EDTA提取态Pb老化速率与土壤pH、电导率(EC)呈极显著负相关,与铁铝氧化物含量呈显著正相关。To investigate the aging of added lead(Pb)in different soils,three typical soils(red earth,black soil,and fluvo-aquic soil)were dosed with soluble Pb and stored for 1,3,9,30,100,and 360 days.Three extractants(0.01 mol·L^-1 CaCl2,0.05 mol·L^-1 EDTA-2 Na,and0.43 mol·L^-1 HNO3)were used to extract available Pb after different incubation periods.The results indicated that the extraction efficiency of Pb added to soils was related to the type of extractant and the properties of soil.The extraction efficiencies of 0.43 mol·L^-1 HNO3(81%~99%)and 0.05 mol·L^-1 EDTA-2 Na(66%~99%)for Pb added to soils were much higher than that of 0.01 mol·L^-1 CaCl2(0.002%~13.8%),which was much higher in red earth(7.2%~13.8%)than in the other two soils(black soil and fluvo-aquic soil,0.002%~0.037%).With0.05 mol·L^-1 EDTA-2 Na,the extraction efficiency followed the order of black soil>red earth>fluvo-aquic soil.The dynamic aging curves of Pb extracted using 0.01 mol·L^-1 CaCl2 and 0.05 mol·L^-1 EDTA-2 Na showed that aging occurred in the short-term in the three soils,then the aging rate decreased with time;however,there was no significant change in the extraction efficiency of 0.43 mol·L^-1 HNO3 over time.The concentrations of 0.05 mol·L^-1 EDTA-2 Na extractable Pb in red earth and fluvo-aquic soil initially decreased rapidly for 30 days,then changed slowly between 100 and 360 days to reach a pseudo-equilibrium.In black soil,the aging process was relatively slower;the times to reach a pseudo-equilibrium for red earth,fluvo-aquic soil,and black soil were 100 days,360 days,and longer than 360 days,respectively.The aging curve of Pb in soil fitted well to a first order exponential decay equation.The aging rates of EDTA-extractable lead showed a highly significant negative correlation with soil pH and electrical conductivity,and a significant positive correlation with the content of iron-aluminum oxide in the soil.

关 键 词：外源Pb 红壤 黑土 潮土 老化过程 提取剂 

分 类 号：X53[环境科学与工程—环境工程]