滩涂土壤淋洗过程中盐分变化及其对重金属的影响

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%、Mg^2＋86.6%、Ca^2＋90%、Cl^-81.8%、SO4^2-98.2%...

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

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+, Mg2+, Ca2+, 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.