The Content of Heavy Metals in Soils and Leaves of Silver Birch Plantations (Moscow)

Abstract

The ecological condition of urban plantations is an urgent problem of our time. The condition of plantations and soils characterizes the ecological and sanitary condition of the environment. In the structure of the cities, urban and forest parks are of particular importance. They mainly perform recreational functions, contributing to improving the health and well-being of city residents. Woody plants, due to their properties to absorb harmful substances that come with air pollution from industrial enterprises and motor vehicles, are one of the main mechanisms for stabilizing the environmental situation in cities. Technogenic pollutants, a significant proportion of which are heavy metals, make a significant contribution to the pollution of ecosystems. Heavy metals represent a specific category of particularly toxic pollutants. The main sources of their entry into the soil are related to human activity. Heavy metals are accumulated by plants, which negatively affects the condition of urban plantations. Soil contamination with heavy metals leads to significant changes in the agrochemical state of the soil and the entire ecosystem. The accumulation of heavy metals in ecosystems depends on various factors, mainly on the condition of the soil and vegetation and the level of anthropogenic impact. The article describes the quantitative content of copper, lead, cadmium, nickel and zinc in the samples of soil and leaves of silver birch growing in the territories of Moscow parks. The sample plots have been laid in different functional areas of the parks: at the alleged sources of negative impact, as well as at points farthest from anthropogenic objects. The results of the study have been compared with the standards for maximum permissible concentrations, the biological absorption coefficient has been calculated, and the accumulation of heavy metals has been revealed depending on the location of the object relative to potential sources of pollution. The soils of the plantations under study contain concentrations of heavy metals that do not exceed the MPC level. The exception is zinc. Its amount in some sample plots has been increased several times. Birch leaves have shown an uneven accumulation of heavy metals depending on both the concentrations of the elements in the soil and the location of the sample plots.