滩涂土壤淋洗过程中盐分变化及其对重金属的影响  

Salinity Change and Its Impact on Heavy Metals During Beach Soil Leaching and Desalination

作　　者：刘亚男[1] 李取生[1] 杜烨锋[1] 崔志红[1] 李莎[1] 

机构地区：[1]暨南大学环境工程系,水土环境毒害性污染物防治与生物修复广东省高校重点实验室,广州510632

出　　处：《环境科学》2011年第7期2087-2091,共5页Environmental Science

基　　金：国家自然科学基金项目(40871154,U0833002);广东省自然科学基金项目(07005931)

摘　　要：通过对滩涂土壤的淋洗实验,对在不同脱盐阶段,土壤孔隙水的盐分离子与土壤中各重金属含量及各重金属不同形态的含量进行监测与分析.结果表明,不同脱盐阶段的土壤孔隙水,淋洗后较淋洗前各盐分离子的下降率分别为:Na+80.3%、K+73.5%、Mg2+86.6%、Ca2+90%、Cl-81.8%、SO24-98.2%,盐分总量下降了81.6%,但是在淋洗过程中孔隙水的化学类型一直是以氯化钠型为主;土壤孔隙水的pH值随着淋洗时间的增加整体呈上升的趋势.土壤中各重金属的含量淋洗后较淋洗前的下降率分别是Cd 26.6%、Pb 22.8%、Cu 16.9%、Cr 7.9%、Zn 9.1%;淋洗前后各重金属的形态分析显示,碳酸盐结合态的重金属离子下降率分别为:Pb 77.8%、Cr 61.7%、Cu 68.4%、Zn 67.1%、Cd 7.1%,铁锰氧化物结合态的Cd和Pb下降率分别是49.1%和23.5%.土壤孔隙水中各盐分离子在淋洗过程中迁移能力不同,导致各盐分离子占总盐分含量的比例发生变化,同时淋洗过程中土壤的氧化还原电位发生改变,这些变化导致土壤重金属的化学形态发生改变,从而影响重金属在土壤中的迁移状况.The salinity ion in soil pore water and the heavy metal content in soil as well as the heavy metal speciation were investigated in various stages of desalination during an experiment of leaching beach soil.Results show that salinity ion including Na^＋,K^＋,Mg^2 ＋,Ca^2 ＋,Cl^-and SO4^2- decreased by 80.3%,73.5%,86.6%,90%,81.8%,98.2% respectively compared to pre-leaching.The amount of total salt decreased by 81.6%.However,the main chemical compound in pore water was NaCl throughout the leaching experiment.The pH value of pore water increased with leaching time.Besides,the reductions of heavy metals after leaching were： Cd 26.6%,Pb 22.8%,Cu 16.9%,Cr 7.9%,Zn 9.1%.The concentrations of Pb,Cr,Cu,Zn and Cd in carbonate bound form decreased by 77.8%,61.7%,68.4%,67.1% and 7.1% respectively.The contents of Cd and Pb bound to Fe-Mn oxide decreased by 49.1%,23.5% respectively.The different mobility of salinity ions in the pore water resulted in the proportion change of each ion.Meanwhile the Eh value of the soil changed in the leaching process.All these factors resulted in the change of heavy metal speciation and the removal of heavy metals in the soil.

关 键 词：淋洗 滩涂土壤 孔隙水 盐分 重金属 

分 类 号：X131.3[环境科学与工程—环境科学]