12. Physicochemical Processes in Groundwater Flow

The chemical property of groundwater depends on the infiltrated substances (mainly from anthropogenic sources) from the earth’s surface through percolating water, as well as on the chemical-petrographic properties of the water-conducting aquifer. During groundwater flow, there are interactions between the aquifer and groundwater bodies with different properties (Luckner and Schestakow 1986). One can assume that the property of the groundwater, i.e. the ion contents (quantitative and qualitative) given in a water analysis, is the result of various physicochemical processes towards a state of equilibrium. Such processes are sometimes called water “diagenesis” or “metamorphosis”. A groundwater analysis should be understood as an expression of this chemical-physical state of equilibrium and can be used through careful interpretation to recognize the processes occurring as a result of groundwater flow. However, because the petrographic properties of an aquifer in the subsoil are seldom homogenous, the states of equilibrium are constantly changing, all the more so with longer flow paths. For this reason, the results of chemical water analyses should only be assessed at selected points and the processes that took place regionally or temporally can only be deduced in comparison with other analytical results. This interpretation of chemical conditions in aquifers should not be performed statically but, rather, dynamically.