Thermodynamic modeling (in the software suite Selector) of the processes controlling the surface and groundwater chemistry in the catchment area of the Malaya Belaya River as part of the water-rock system made it possible to identify the migration forms and ratios of vital, carcinogenic, and toxic elements. It was found that the surface and groundwater chemistry is controlled by the interactions of surface, ground, and fissure water with the nepheline syenites and chibinites of the Khibiny massif, which is supported by the data on the concentrations of heavy isotopes of hydrogen and oxygen (δ18O and δ2H). The natural water chemistry and the element ratios may be causes of some of the diseases common among the area's residents, since these diseases are due to the excessively high or low or out-of-balance concentrations of many biologically important components and ratios thereof.
Keywords: catchment; groundwater and surface water; physicochemical modeling; rocks; the Khibiny Massif.