Long-term studies of the North Caucasian geochemical province allowed to establish regional abundances and calculate accumulation (dispersion) factors for chemical elements in rocks, soils, and plants. Certain natural regional patterns characterize the province. Associations of elements in high and low concentrations are often determined by the predominant composition of rocks: carbonate-terrigenous, terrigenous, and igneous. The study of the average contents of several chemical elements in the soils of the province showed that the association of accumulated elements includes metals with different migration characteristics. Thus, despite the rather close values of the ionic radii, Pb, Zn, Cu, and Li (judging by the ionic potential) are characterized by the formation of cations, while Mn, Mo, and Zr form complex ions. Such elements as Zn, Cu, and Pb are mainly accumulated on hydrosulfuric barriers, while Mo, Co, and Mn are stopped by oxygenous barriers. For Cu, Zn, Mo, and Co, biogenic accumulation plays a significant role, while for Pb and Ni it is practically absent. The absolute dispersion of the elements did not reach environmentally hazardous values, although it indicates a fairly intensive migration. In woody plants, Ba, Nb, Sc, Sr, and Zn are accumulated most intensively.
The data on the geochemical features of the bedrocks and soils of the province are given. Considerable attention is paid to regional abundances, as well as enrichment and dispersion factors of the chemical elements in landscapes. Using the example of the North Caucasus, it is shown that for such indicators as phytomass, geological, geomorphological, and geobotanical features, it is possible to make a preliminary outlining of regional structures corresponding to geochemical provinces. At the same time, a subsequent geochemical study of these structures remains mandatory. Upon determining certain geochemical associations, geochemical provinces can be basically distinguished; to a large extent, geochemical properties of these accumulated and scattered associations of elements contribute to the regional soil geochemistry. The results of long-term monitoring studies of the North Caucasus geochemical province have shown that the key features of the regional landscapes are due to the composition of bedrock and the presence of a large number of ore deposits and occurrences. The data obtained are the basis for assessing the state of the environment in conditions of increasing anthropogenic impact, and the established regional abundances can be used to assess the degree of pollution in agricultural, residential, and mining landscapes.
Agrolandscapes make up the largest part of the world's man-made landscapes. Their soils are subjected to annual mechanical cultivation; fertilizers and toxic chemicals are applied. All this leads to specific contamination of soils with a number of chemical elements. All over the world, certain agro-landscapes are periodically withdrawn from agricultural turnover. In this regard, it is important to answer the question: whether geochemical "soil self-remediation" is possible in this case or not. If geochemical self-recovery is possible, it is desirable to know how long it can happen. We have developed a methodology of works on the basis of monitoring studies. On its basis this problem was considered for tea plantations of the Western Caucasus.
The results of environmental and geochemical monitoring of agrogenic transformation of landscapes in the Western Caucasus, different with respect to the application of various types of agronomic load are presented.
Difference of climatic factors, complex relief, peculiarities of soil-forming and soil-bearing rocks, soils, vegetation cover determined the diversity of floodplain geochemical landscapes of the Western Caucasus. A large area of floodplains in the Western Caucasus is occupied by biogenic landscapes. Economic activities of man during the development of floodplains largely transformed the original natural landscapes. Some of them have been partially changed. For example, deforestation led to the change of its species composition. Other natural floodplain landscapes disappeared altogether, and new man-made landscapes (mainly agricultural and residential) appeared in their place. Comprehensive detailed studies of floodplain landscapes of the Western Caucasus have allowed us to assess the ecological and geochemical condition of forest ecosystems and the dynamics of its change during technogenic transformation.
An environmental-geochemical study was carried out for the landscapes of the Black Sea coast, dividing the territories into regions according to the nature and degree of technogenic impact. A map of geochemical landscapes of Tsemesskaya Bay was drawn up. For the purpose of their biogeochemical assessment, some species of laurel, kelp and green algae growing in the coastal zone were analyzed to determine the concentrations of 20 chemical elements in their ashes. Some elements (Pb, Mn, Cu, Co) characterized by predominant accumulation in cystosira with significant general pollution of coastal areas of the bay were identified. In 1999 there is a slight decrease in the concentrations of some elements in the ash of the studied algae compared to the previous year. In 2000, some increase of element concentrations in ashes of the observed algae was observed.
As new ecological and geochemical indicators of ecosystems state it is proposed to use the indicators of absolute (IAA) and relative (IRA) accumulation of chemical elements in certain geochemical systems. The example of forest landscapes of the Western Caucasus shows the change of these indicators during the transition to landscapes of orchards, rain-fed fields, rice checks. In the soils of the considered anthropogenic systems various elements affecting the chemical composition of agricultural products are accumulated and removed from them.
