The results of research on the content of water-soluble fluorine in the soils and vegetation of the Carpathian Biosphere Reserve (KBR) are presented. Analyzes were performed using a spectrometric spectrometer with alizarin-complexone on a Specol 11 spectrophotometer. Based on the results of statistical processing of the analysis, the limits and background content of water-soluble fluorine were established in soils on the plots: Yasynska — 0.1—1.34 mg/kg (background — 1.1 mg/kg); Rakhivska — 0.1—2.86 mg/kg (background — 1.4 mg/kg); Bohdanska — 1.34—1.9 mg/kg, (background — 1.6 mg/kg) (total background content — 1.34 mg/kg). It was determined that in the soils of the areas located in the zone of tectonic disturbance (v. Kvasy) the content of fluorine is greater than the background (1.35—1.4 mg/kg), its intake occurs together with mineral waters and gases. It was found that the maximum content of water-soluble fluorine (1.6—2.6 mg/kg) in in sod-podzolic soils (light and medium loamy) of the Marmaros massif, which is associated with increased humidity and the presence of kaolinite component of clay minerals, which does not bind fluorine into hard-to-reach compounds, subalpine) and the content of water-soluble fluorine in soils, at the same time, a weak negative relationship between the steepness of slopes (gentle, steep, precipitous) and the content of water-soluble fluorine in soils (the lower the steepness of the slope, the higher the content of water-soluble fluorine) was found. Biogeochemical properties for water-soluble fluorine (according to the biological absorption coefficient, Ax) of nine types of plants were established: evergreen conifers (pins and branches) — Táxus baccáta L. — 15.5; Thuja — 5, Abies alba — 5; birch family (branches and leaves) — Corylus avellana L. — 6.1, Alnus glutinosa (L.) P. Gaertn — 2.8; grasses (leaves and flowers) — Betonica officinalis L. — 4.6, Centauréa jacea — 6, Senecio vulgaris L. — 4.3, Filipendula ulmaria — 3.9. The concentrator of water-soluble fluorine is the pins and branches of the Taxus baccata L.
