Naturel water cycle et hydrochimical evolution

Abstract

This document is a handout of hydrochemistry that presents natural water chemistry as the science studying the composition, reactions and evolution of dissolved substances in groundwater and surface water, in relation to thermodynamics, acid-base and redox balances, and water resources management. It recalls the basic notions of the structure of the water molecule, its properties related to hydrogen bonds, the definition of solutions, dissolution, conductivity, as well as ion formation, ionization energies, redox couples and oxidation-reduction reactions. He then describes the different expressions of concentration (mass, molar, equivalent, activity, ionic strength) and the major processes of chemical alteration of rocks and waters (hydration, hydrolysis, oxidation, reduction) that control the formation of soils, the mobility of metals and the geochemical evolution of water.