Alexey Ivanovich Shcheglov

The review provides a brief description of ecotoxicodynamics as a section of environmental toxicology including the subject of research, theoretical underpinnings and relevant studies. It has been shown that the development of ecotoxicodynamic studies at the present stage associated with the assessment of environmental quality and risk, establishing a database for ecological regulation, analysis of the processes of degradation and self-restoration of natural ecosystems.Particular attention is paid to the analysis of achieved successes in the study of the action of ecotoxicants on the example of their new types (nanoparticles, microplastics, harmaceuticals, food additives). The potential for them to exhibit toxic effects from genetic to ecosystem level including with real existing content has been demonstrated. The effects in organisms manifest as geno- and cytotoxicity and are reflected in violations of the reproductive, immune, enzymatic and digestive systems, behavioral reactions, decrease the rate of growth and development of organisms, the rate of photosynthesis, etc. In ecosystems the consequences of these effects may be а decline in the number and extinction of sensitive species, negative changes in interspecies relationships, loss of biodiversity and productivity of the biocenosis. Gaps in the study of new ecotoxicants are shown, to eliminate them promising research directions have been proposed in particular: investigations оn sublethal effects under real ecosystem loads, assessment of the possibility of developing chronic and delayed effects, detection of the influence of ecotoxicant properties and environmental factors оn toxic effects as well as consideration of combined effects of several ecotoxicants and products of their transformation. The problematic aspects in the study of ecotoxicants were noted by authors of the reviewed research papers. They are (1) the differences in the "scenario" of experiments among different authors, that make comparative assessment difficult to identify general patterns of possible ecotoxicant action in the environment, (2) application model experiments with standard media, that do not reflect real natural conditions and reduce the practical significance of the results obtained.