The results of a study on the content of potassium and calcium in plants of the Middle Mountain province of Dagestan are presented. The content of macroelements was determined on «Savant AA Σ» atomic absorption spectrometer. The K content in plants varied from 0.16 to 3.21%, Ca - from 0.02 to 3.47%. The content of mobile forms of elements on the northern slope is slightly higher than on the southern (1.2 times). The coefficient of biogeochemical mobility K ranges from 5 to 100.3, Bx Ca – from 1.2 to 204.1. On the southern slope, K and Ca are most actively absorbed from the herb-cereal phytocenoses Plantago media, Plantago lanceolata, Lotus corniculatus, Trifolium medium, Inula britannica, Achillea millefolium, Psephellus daghestanicus, Galium verum, Astragalus onobrychioides, Medicago glutinosa. On the northern slope, K, Ca Astrantia biebersteinii, Inula germanica, Trifolium campestre, Vicia truncatula, Vicia cracca, Betonica macrantha, Origanum vulgare, and Betonica orientalis accumulate most actively. The least accumulation of K and Ca is observed in plants of the Poaceae family. The difference in the content of K and Ca in plants depends on the content of mobile forms of elements in the soil, biological characteristics of plants, and environmental factors.

The aim of the study is to determine the role of geochemical factors (the content of Mg, K, Ca, Zn, Pb in soils and natural waters of the plain zone of Dagestan) in the prevalence of essential arterial hypertension (EAH) among the population of children. Materials and methods of research: an observational cross-sectional (one-step) study of the prevalence of EAH in the child population was carried out. The prevalence rates of EAH among children in the plain zone of the Republic of Dagestan are calculated for 100,000 children 0–17 years old, without taking into account gender differences. The content of elements (Mg, K, Ca, Zn, Pb) in the environment (soil, natural waters) was determined by atomic absorption spectroscopy. Results: one-way analysis of variance (One-Way ANOVA) of indicators of the content of metals (Mg, K, Ca, Zn, Pb) in the regions and objects (soils, natural waters) of the study revealed a statistically significant difference in the data (for soils: F=81,06772, p<0,0002; for natural waters: F=58,86451, p<0,00001). The dependence of children's EAH on the content of chemical elements in the objects of the biosphere of Dagestan was determined, which was expressed in an increase in the number of patients with EAH when Pb content exceeded (r=+ 0,576, r=+ 0,759) and with the decrease of Mg (r=–0,668, r=–0,173), K (r=–0,440, r=–0,636), Ca (r=–0,693, r=–0,533), Zn (r=–0,051, r=–0,827) in soils and natural waters. Conclusion: when assessing the pathogenesis of EAH in the population of children, the content of Mg, K, Ca, Zn, Pb in soil and water should be taken into account, since these microelements, entering the body with water and food, affect the elemental status of child's body.

Studies conducted in 2012-2019 on two permanent trial protected areas of the Mid-Mountain sub-province of Daghestan show that phytocenoses growing on the slope of the northern exposure of Mount Mayak accumulate more nitrogen than phytocenoses on the southern slope do.