Vera Alexandrovna Terekhova

Bioassay is a popular method for the ecotoxicological state assessment of various components of urban ecosystems — soils, water bodies and air. However, little is known about the potential of bioassay application to determine the ecotoxicity of urban dust — a complex heterogeneous media composed of natural and technogenic particles.
Many components of urban dust are known to pose toxic eff ects to living organisms. The aim of this article is to review the existing practices for the ecotoxicological assessment of urban dust and to identify the key trends in the development of the bioassay. The existing studies revealed a high potential of bioassay methods as they are sensitive to a wide range of pollutants present in dust; able to refl ect the dust toxicity selectively depending on environmental factors, and can be implemented using organisms of diff erent trophic levels. The following dust characteristics should be taken into account for the bioassay method proper choice: sample mass, wettability, pH, water-soluble ions and organic matter content. Due to complexity of urban dust composition and diff erent potential for the transition of its components into water extracts, it is recommended to prioritize the bioassay realized on solid dust substrates
instead of extracts. For the comprehensive assessment of dust impact on urban ecosystem, a set of organisms of different
trophic levels should be considered instead of one. Standards should be developed for dust bioassay in order to unify the results obtained by diff erent researches. Th e choice of the control sample is one of the most important
methodological questions.

Th e methodology for biodiagnostics of the ecological state of soils and other environmental objects involves the use
of two approaches: bioindicative observations in situ and biotesting of samples, carried out according to standard methods in controlled laboratory conditions ex situ. An integrated assessment of soils on an interdisciplinary basis in accordance with the international standard ISO19204-2017 makes it possible to diagnose of soils “health” based
on biotic parameters in the course of natural environmental observations, ecotoxicity indicators, which are supplemented
by the results of quantitative chemical analysis (TRIAD methodology). For soils, indicators of the state of higher plants and microbial communities, especially in agroecosystems, are of paramount importance. The article analyzes the advantages and limitations of well-known methods of phytoindication, laboratory phytotesting, soil
respiration, structural and functional indicators of microbiota diversity and bacterial biosensors. Th e responses of living systems to the same pollutant content largely depend on the carbon content of organic matter. The existing regulatory framework for the ecological assessment of the biological state of soil ecosystems practically does not take into account this, as well as the level of mineralization and pH of the analyzed objects. For an adequate assessment of the ecological quality of soils, it is proposed to improve the methods of measuring toxicity by more targeted recommendations for application (for example, for certain gradations of humus content, mineralization, pH).

The most promising areas of ecological assessment, regulation and quality management of soils and lands are: the study of their ecological functions and the role of the anthropogenic factors in the formation of the natural complex of lands that has developed within land plots, taking into account natural conditions, the type of land use and the relationship with natural environments; study of natural connections between the soil cover and subsurface geological layers; determination of permissible changes in soil quality during oil pollution, forest and peat harvesting taking into account the prospects of natural self-restoration of landscapes; the study of direct and inverse relationships of soils, aquatic environments and amphibian landscapes in conditions of land pollution; identification of the func- tional relationship between the state of soils and the quality of atmospheric air; study of aspects of contact of soils and other components of the environment with waste. The analysis of the existing legal norms aimed at protecting soils as a component of the environment allowed us to conclude that the structure of environmental legislation is incomplete, within the framework of which, among the existing federal laws regulating the protection of environ- mental components, a Law on Soil Protection needs to be developed.