Olga Vyacheslavovna Nikolaeva

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.

A significant factor contributing to the degradation of turfgrass in urban areas is the use of chloride-sodium anti-icing agents (AIA). Despite extensive research on the salinization of urban soils, studies assessing the impact of sodium chloride on turf grasses are insufficient. This work evaluated the phytotoxicity of the most common grasses used for lawns in Moscow: red fescue (Festuca rubra L.), creeping bentgrass (Agrostis stolonifera L.), perennial ryegrass (Lolium perenne L.), and white clover (Trifolium repens L.), using the laboratory phytotesting method. The plants were exposed for seven days to soil mixtures with sodium chloride concentrations of 0.1%, 0.5%, and 1.5% (w.). The observed parameters were «root length of seedlings», «shoot length of seedlings», and «seed germination». The studied species showed different levels of sensitivity to soil salinization, and the study highlighted the importance of simultaneous analysis of various growth and development parameters for making informed decisions on the optimal plant species for urban greening. The greatest differences in phytotoxicity were found in the «root length» parameter at high concentrations of AIA (1.5%) and in the «seed germination» parameter across the entire range of salt contamination. The proposed algorithm for selecting optimal plant species in saline soil conditions suggests starting by analyzing phytotoxicity results based on germination, selecting plants with minimal inhibition of this parameter. Then, among these, choose those that also showed the lowest phytotoxicity in terms of root and shoot length. Based on the results of the study, creeping bentgrass is recommended as a universal salt-tolerant species, along with perennial ryegrass at sodium chloride concentrations of 0.1% and 0.5%.