北京地区不同介质的土柱淋滤水质试验研究

为探讨冲洪积平原地带地下水水质劣变机理及过程,开展了不同的水土样品组合的16组淋滤试验,以期揭示不同源水在土柱入渗过程阴阳离子、硬度和TDS的变化规律以及地下水类型的演化特征。试验结果表明:淋出液中,阴离子浓度的变幅由大到小依次为HCO_3~-、NO_3~-、SO_4~(2-)、Cl~-和F~-,阳离子的变幅则依次为Na~++K~+、Ca~(2+)和Mg~(2+)。淋出液的硬度、TDS和水化学类型均呈现出有规律的变化,先期主要受控于源水,尔后则主要受土柱介质的影响。除了以垃圾作为淋滤介质的试验外,其他组合的试验都出现了初期TDS和硬度升高的过程,之后与源水趋于一致,揭示了淋滤中浸泡—水岩相互作用—吸附解析—淋洗等复杂过程。

Leaching Experiment on Water Quality of Different Soil Columns in Beijing Area

In order to illustrate the evolution mechanism and process of regional groundwater quality in the city within the alluvial plain area, a total of 16 different sets leaching test of soil/water samples were carried out in Beijing area. The transformation characteristics of different sources of water anions and cations, variation of hardness and TDS as well as the type of groundwater in the soil column infiltration process were revealed. By comparing the concentration of source water and leaching solution, three main results were presented as followed: In the leaching solution, the change range of anion concentration is HCO3-, followed by NO3-, SO42-, Cl- and F-. The amplitude of the cation is in the order of Na++K+, Ca2+and Mg2+. The hardness, TDS and hydrochemistry types of leachate showed a regular change. In early stage, the quality of leaching solution is mainly controlled by the source water, and then is mainly affected by the soil column media. Excepting the experiment using waste as leaching media, the initial TDS and hardness increase process appeared in the all other experiment combinations, and then it was consistent with the source water, which revealed the complex processes such as the leaching, water-rock interaction, adsorption analysis and so on.