三江平原典型区地下水铁的动态变化

摘要

为揭示地下水铁的时间变异规律和影响机制,对三江平原典型区不同深度的地下水水位和铁开展了动态监测,分析了总铁含量和形态的季节变化特征及其与地下水位波动的关系.结果表明:地下水为中性偏弱酸、强还原性环境,铁在浅层和中层富集.地下水铁的动态变化和水位关系密切,随着地下水位的上升、下降,总铁含量和Fe2+质量浓度也随之增加或降低.浅层地下水对水位变化响应迅速,中层地下水存在滞后.地下水位的季节波动导致含水层氧化还原条件改变,影响了水岩体系中铁的迁移和转化.%To understand temporal variation of iron occurrence and formation mechanism in groundwater,water level and iron in groundwater at different depths in a typical area of Sanjiang Plain were monitored.Seasonal variation of total iron contents and speciation were analyzed,as well as it's relationships with groundwater level fluctuation.Results showed that groundwater was neutral weak acid,negative Eh with iron enriched in upper and middle layer groundwater.Dynamic changes of groundwater iron and water level were correlated closely.The contents of total iron and Fe2+ were higher together with higher groundwater level,and decreased with drawdown of water level.Iron in shallow groundwater responded rapidly to the water level fluctuation,while it had a hysteresis effect on groundwater level fluctuation in the middle layer groundwater.It was indicated that redox conditions changed with groundwater level fluctuation,which had a significant effect on the mobilization and translation of iron in rock-water system.