The geochemical composition of waters of the Mzymta River is subjected to sharp seasonal changes. In summer, the waters are enriched in 34 elements (mainly REE, Fe, Mn, Cs, Al, and Cd) relative to their average contents in river waters. REEs in the waters show steady relations MREE > HREE > LREE with a general positive trend to the mouth. In spring, they are enriched only in 14 elements. They have the poorer REE composition and less fractionated REE patterns. In summer, their contamination significantly increase relative to MPC, with growth from the upper reaches to the river mouth. A general geochemical specialization of bottom sediments is determined by 27 elements, contents of which insignificantly exceed their average contents in rocks exposed in the basin for the upper continental crust. Disagreement between the high level of water contamination in summer and a weak contamination of the bottom sediments of the river is related to the low contents of finely dispersed mineral and organic matter in the latters. It was determined that chemical elements are supplied in water from three main sources: natural, natural–technogenic, and anthropogenic–technogenic. The maximum contribution to the water contamination over the entire river extent is provided by natural sources: rocks that compose the basin. The anomalous increase of concentrations of chemical elements, including Th and Y, in the middle and lower reaches of the river is related to the natural–technogenic sources at the adjacent slopes of the valley. These are technogenic areas and talus, as well as highway and railway roads, and sometimes building embankments, which are made up of disintegrated rocks devoid of soil–vegetation layer. The anthropogenic–technogenic factors make only a limited contribution to the contamination of water and bottom sediments of the river. The radioecological state of waters and bottom sediments of the Mzymta River is safe.

It is found that the overwhelming majority of mobile forms of the chemical elements (up to 99%) that are thought to produce favorable effects when they arrive with volcanic ash to soils and supply additional elements that enhance the bioproductivity of ecosystems do not come in the form of ash particles, but in a gas-dissolved form directly from volcanic aerosol. Volcanic ash when considered independently of volcanic eruptions does not contain considerable amounts of accessible forms of chemical elements that would enable us to consider them as sources of nutrient elements for living organisms. However, the extensive range of elements that are contained in ash in ratios that are necessary for effective life activities invests these elements with catalytic properties that regulate the nutrient regime of plants and that can be used in agriculture in combination with lower amounts of traditional fertilizers to produce substantial (up to 72%) yield increases and to improve the quality of agricultural products.

The microelemental composition of volcanic soils of Kamchatka is specified by the composition of the volcanic ashes from which these soils are developed. It is found that the soils developing from aci

The link of the chemical composition of the plant with the active volcanism of Kamchatka, is determined by the stable occurrence into the composition of the priority chemical elements for plants, volcanic ashes and soils: Ca, Mg, Mn, P, Cu, Zn and Sr. An elevated geochemical background of Kamchatka plants relative to the bulk chemical composition of the peninsula’s soils was established. The contents of Br, Hg, Hf, Sb, Ga, W, K relative to the clarks for living matter in the plants of the region are exceeded by 3–5 times. Against the background of small variations in the contents of chemical elements in plants of different regions, the relatively rich biogeochemical background of the Western region of the southern province (the western coast of Kamchatka) is determined, where most ancient near-surface volcanic ashes for Kamchatka are transformed into humus-accumulative horizons. On the territory of young volcanic ash fallout in the immediate vicinity of volcanoes, the relative richness of vegetation with chemical elements and the poverty of soils by mobile forms of elements have been established. On the contrary, at a distance from the volcanoes in the zone of far transfer fallout ashes, there is a marked relative poverty of plants and soil richness of available chemical elements.

The Mzymta and Sochi watersheds, located on the southern slopes of the Caucasus Mountains on Russia’s Black Sea coast, are characterized by a remarkably complex geological setting. The predominant rocks are mudstones, siltstones, and shales, with smaller amounts of carbonate and clay-carbonate rocks, and occasionally igneous rocks. The area is also characterized by the occurrence of polymetallic, gold, sulfide, rare metal, and rare-earth mineralizations in addition to hosting a thermal hydrogen sulfide groundwater aquifer. The objective of this study was to determine groundwater genesis patterns in an area with such contrasting geological and hydrogeological structures. Based on the chemical analysis of 33 natural groundwater springs, five chemical types of water were identified dictated by the composition of the host rock as well as the occurrence of mineralizations, seepage of mineralized water, and local geochemical features of the host rock. The high sodium concentration and mineralization of groundwater near the thermal hydrogen sulfide groundwater aquifer are due to the infiltration of seawater. The consistent presence of excessive amounts of rare-earth elements (REEs) in all groundwaters in the area is a reflection of the regional geochemical specialization of the rocks. Groundwater, like the terrestrial components of the natural environment, inherits rare-earth fractionation patterns from the rocks that make up the area. Thus, rare-earth totals and fractionation patterns can be used as a reliable criterion to interpret the regional specificity of groundwater.