Abstract
Major element (Si, Al, Na, K, Ca, Mg, Fe, etc.) concentrations in groundwater are determined by rocks (minerals) interacting with rocks (minerals), degree of water-rock interaction, dissolution rate, precipitation rate and solubility of minerals, specific surface area of minerals, and flow rate of groundwater. In order to interpret groundwater quality variation, various theoretical models (chemical equilibrium, reaction kinetics, mass balance, reaction-flow coupling model) are used. Based on these models the variation of groundwater quality with altitude in basaltic (Fuji area) and granitic (Tsukuba area) areas is interpreted. It is intended to estimate groundwater residence time based on reaction-flow coupling models. Anthropogenic influence on groundwater quality is discussed, considering the cause for the difference between analytical groundwater data and theoretical model calculations.
