[en] The purpose of this study has been to simulate the hydrochemical evolution of dilute water, typical of melt-water in a glaciation scenario, infiltrating into bedrock. The focus is on the alkali and alkaline earth cation compositions because these might affect the performance of bentonite buffer. A geochemical model of batch reactions between dilute water and rock minerals has been constructed. Two approaches to simulating these hydrogeochemical reactions have been implemented using the PHREEQC program. The first approach has simulated the dissolution reactions of various aluminosilicate minerals in terms of the rates of each reaction. The potential for continued dissolution is governed by the calculated state of thermodynamic equilibrium for each mineral phase, but the progress of dissolution is calculated using empirical kinetics expressions. The second approach has assumed that local equilibria are achieved rapidly between water and reactive minerals so that hydrochemical evolution is governed by equilibria with different assemblages of minerals. Sequential equilibria with various permutations of mineral assemblages have simulated how the resulting groundwater compositions, specifically the pH and the [Ca²⁺+Mg²⁺]/[Na⁺] ratio, depend on the selected mineral assemblages. The equilibrating secondary minerals for both modelling approaches are calcite, chalcedony, kaolinite, illite and chlorite, plus montmorillonite in the local equilibrium model. The minerals selected for kinetic dissolution reactions are albite, anorthite, K-feldspar and biotite. The minerals selected for dissolution-only equilibration are laumontite, saponite, prehnite, albite, anorthite and K-feldspar. Model runs were constructed to represent various combinations of these minerals in three stages of local equilibrium. The main conclusions to be drawn from this modelling study are: (i) The realistic and most likely scenarios for hydrogeochemical evolution would result in divalent cation concentrations and (Ca+Mg)/Na ratios that would not challenge the safety function indicator criterion, Σ[M²⁺]≥10^-3 M; (ii) There are specific hydrogeochemical scenarios that in theory could result in groundwater compositions at repository depth that are depleted in Ca²⁺ and Mg²⁺ concentrations. This modelling study provides some insights about the hydrogeochemical evolution of dilute water if it reaches repository depth without having mixed with pre-existing brackish or saline groundwaters. Such an influx of dilute water is perceived to be particularly possible due to melt water infiltration during a future glacial period. The issues, illustrated by this study, of reactions between minerals and dilute water should be further explored to better understand the hydrogeochemical aspects of the glacial meltwater intrusion scenario. The present study indicates potential issues but has not had the scope for a sensitivity analysis and an investigation of uncertainties