Influence on increasing of shallow groundwater hardness with water-soil interaction

The shallow groundwater hardness has been increasing, which has become a widespread groundwater pollution problem. The paper designed laboratory experiments of leaching to simulate water-soil interaction in the study area to analyse the mechanism of groundwater hardness increment. It is quite necessary for regional protection of quality of underground water, rational development and utilization of underground water. The water sample from underground water, the soil sample include that polluted soil, farmland soil, and clean soil.The results were as follows: Water-soil Interaction can led to total hardness increase on leaching solution; Soluble salt、K+、Na+positive ion and TDS had close relations with total hardness. During water-soil interaction, dissolution effect、cation replacement function replacement and salt effect were occurred and led free calcium magnesium ions、exchangeable calcium magnesium and combined calcium magnesium in soil into groundwater, the hardness of groundwater rise significantly.