In this article, the effects of high concentrations of four types of organic solvents (benzene, toluene, chloroform, pyridine) on three types of aquatic plants (Ceratophyllum demersum L., Elodea​ canadensis Mchk., Chara fragilis D.) were studied. The experiments were conducted in laboratory (freshwater) microcosms. The tested pollutant concentrations reached 5000 times the Maximum Allowable Concentration (MACs). The incubation temperature was maintained at 24±1.5°C, with observations spanning 7 days (168 h). Macrophyte C. fragilis could not remain viable (death within 24 h). Macrophytes C. demersum and E. canadensis showed a relatively high level of resistance to water pollution by pyridine and chloroform. Therefore, these species may serve as potential candidates for phytoremediation of aquatic environments contaminated with these substances.

The uncontrolled spread of invasive non-native species can have significant ecological, social and economic consequences. This paper provides numerous examples of how Elodea canadensis Michx. interacts with various environmental contaminants. Previous experiments have shown that Elodea has a rather high phytoremediation potential. Therefore, there is interest in cultivating this plant for phytoremediation purposes. This article describes the pros and cons of Elodea that society faces when dealing with this plant. The aim of the article is to investigate the invasive capacity of elodea (Elodea canadensis) when introduced into a freshwater body inhabited by other aquatic plant species. Three years of experience are described in this article and it has been shown that E. canadensis quickly adapts and multiplies in new water ecosystems (central Russia) and displaces other aquatic plants. For this reason, it is convenient to grow E. canadensis in incubator ponds and then use it for phytoremediation. The reported results add to the evidence that E. canadensis is a weed of waterways and a nuisance to navigation, but is useful in remediating aquatic environments from anthropogenic pollution. The article is of interest to researchers working in ecology, hydrochemistry, hydrobiology, various environmental and biosphere sciences.

This publication is a response to a book on the problems of environmental chemistry and toxicology of the environment, including the aquatic environment of ecotoxicology, which are relevant, and their relevance increases over time.

The concentrations of synthetic surfactants in wastewater can exceed 30 g/L. The hazard posed by these substances needs to be demonstrated. E Color powder laundry detergent exhibited stronger toxicity toward Vigna radiata seedlings than Arau liquid laundry detergent at all the concentrations tested. The incubation in all Petri dishes lasted for 96 h. Arau caused no toxic effect at concentrations of 0.05 and 0.5 g/L; E Color produced toxic effects at these concentrations. The new data show that Vigna radiata is applicable for assessing the hazard of pollutants.

The indiscriminate use of synthetic laundry detergents (SLDs) triggered notorious prevalence of toxic pollution in water environment.SLDs synthesized from surfactants and other chemical compounds pose ecotoxic risk to living organisms once invading the ecosystem.The widespread presence of terrestrial vegetations in ecosystem may be subject to exposure to SLDs.It is important to test phytotoxic effect of SLDs on terrestrial plant species and form a system of phytotoxic risk assessment.The phytotoxicity of "Tide" detergent powder (TDP) was tested using Lens culinaris seeds as a bioassay.The bioassay showed that the seed germination percentage (ca.0% -90%) reduced sharply due to an increase in TDP concentrations (0.0%, 0.1%, 0.5% and 1.0%) within 72-h and 96-h, respectively.Meanwhile, the increasing concentrations inhibited root elongation (ca.0.0 -8 mm) after 72-h long exposure to TDP, and also impeded root elongation (ca.0.0 -17 mm) after 96-h.The phytotoxicity was assessed depended on two indices: seed germination and root elongation indices.The present study validated an effective and economical bioassay, in which the phytotoxicity ranks (slight, moderate, high and extreme) were graded.

To understand the mechanisms of formation of water quality in an aquatic ecosystem, the processes of formation of funds of dissolved organic matter (DOM) and detritus are essential. When the algae die off, the bulk of their contents enter the aquatic environment within one week. Detritus settles at a rate of about one meter per day. In deep water bodies, the destruction of detritus occurs to a significant extent in the water column; in shallow water bodies, it occurs mainly at the bottom. DOM is consumed by bacteria and algae. This article presents the results of an experimental study of the quantitative aspects of DOM transformation and metabolism using natural water samples immediately after they were taken from a mesotrophic freshwater ecosystem. The total heterotrophic activity of various fractions of plankton in natural water was determined. The specific heterotrophic activity (per a unit of biomass) was also determined. It was found that the specific heterotrophic activity of bacteria (per a unit of biomass) in all cases is higher than the activity of phytoplankton. The new results provide a detailed understanding of chemical-biotic interactions in aquatic ecosystems, which is important for the analysis of water self-purification processes.

Results from decades-long authors’ research on the natural ecosystems of several freshwater water bodies in the Central Region of the European part of Russia were summarized. In particular, the process of formation of dissolved organic matter (DOM) after death of phytoplankton cells was studied in experiments with natural water samples. After the death of phytoplankton cells the destruction of dead cells and release of some part of the cell contents into the aquatic environment as dissolved organic matter occurred within one week. In the first three days bacteria consumed ~50% of the DOM thus released, and subsequently up to 30‒35%. Experiments with plankton of natural water samples collected from June through September showed that ~70% of the organic matter secreted by living phytoplankton cells and ~40% of that released into the water after the death of phytoplankton cells was consumed by bacterioplankton. Also studied were quite a number of other aspects of interactions between DOM, phytoplankton, bacteria, and detritus. For the first time, detailed quantitative data on the detrital particles in the aquatic freshwater ecosystems and some data on the formation and oxidative biodegradation of DOM by plankton, as well as many other quantitative data were obtained.

: Results of research of effects of a chemical product which contains synthetic surfactants on plant seedlings are presented. The chemical product studied was a shampoo made in China, namely, Ginger Polygonum Multiflorum Nutrient Shampoo. This is a herbal shampoo that contains lauryl polyether ammonium sulfate, ammonium lauryl sulfate, and components of medicinal plants. Effects of this mixture chemical product on Vigna radiata were studied. It was shown that at some concentrations, water solutions of this chemical product produced toxic effects on the plant seedlings. At a concentration of 0.5% and after the 48-96 h exposure, the shampoo produced toxic effects and caused a more than 50% inhibition of the root elongation. The new results are in full accord with the previous experiments conducted by the research group of

Previously, toxicity of some synthetic detergents (including laundry detergents) to the plant seedlings of several species of terrestrial higher plants was discovered in research conducted at Moscow University by S.A.Ostroumov. A new example of toxicity of a laundry detergent to plant seedlings was found in this study. The synthetic detergent tested, namely the liquid laundry detergent (LLD) “Blue Moon”, which was manufactured by Blue Moon Group Co, Ltd (Guangzhou, China), produced noticeable phytotoxic effects on the plant seedlings of the terrestrial higher plant Lens culinaris. This detergent at the concentrations 0.5 % - 1% induced a pronounced decrease in the average root length of the seedlings of Lens culinaris. The concentration 5% was lethal to Lens culinaris.Keywords: ecotoxicity, detergent, bioassay, terrestrial higher plants, plant seedlings, root elongation, phytotoxicity, environmental toxicology, Lens culinaris

Dissolved organic matter (DOM) is one of the important parameters of water quality in aquatic ecosystems. In the experiments, phyto- and bacterioplankton actively consumed 14C-labeled chlorella hydrolyzate. Removal (by filtration) of cyanobacteria from the aquatic environment leads to an increase in the rate of DOM consumption by bacteria. This indicates the possibility of a negative effect of cyanobacterial metabolites on the physiological processes of bacterioplankton.

Four innovations added to the V.I. Vernadsky’s concepts on the biosphere in recent author’s publications were summarized. These innovations are as follows: (a) a new typology of the matter in the biosphere; (b) modernization of the concept of the biogenic migration of chemical elements; (c) a new, fourth, biogeochemical principle; and (d) a more detailed presentation of the concept of a substantial influence of organisms on physical and chemical parameters of the biosphere: namely, the development of a new theory of the multifunctional role of the biota in water self-purification in the hydrosphere.

V.I. Vernadsky (1863‒1945) formulated three biogeochemical principles. These principles were set forth, e.g., in his monograph ‟The Chemical Structure of the Biosphere of the Earth and Its Environment” (the first biogeochemical principle was given in Paragraph 95 of that his monograph, the second biogeochemical principle, in Paragraph 198, and the third biogeochemical principle, in Paragraph 208). In addition to those fundamental principles, the author attempted formulating an additional, fourth (4th) principle, consistent with Vernadsky’s ideas on the important role of organisms in modification of the chemical parameters of the biosphere. The new principle highlights additional aspects of the vital role of living organisms in conditioning the geochemical environment. The fourth principle emphasizes a regulatory role of organisms in abiogenic migration of chemical elements in the biosphere.

-Studies of epilimnion, metalimnion, and hypolimnion are of great importance for understanding the vertical structure and functioning of aquatic ecosystems. The present article reports new facts related to the stratification of freshwater ecosystems. In particular, the concentration of dissolved oxygen, temperature, and hydrobiological parameters at depths from 0 to 30 m of Glubokoe Lake (Moscow oblast) were determined. The metalimnion (thermocline) which is characterized by a high vertical temperature gradient was found to accumulate a large amount of detritus and contain increased amounts of bacteria and algae cells (phytoplankton). The increased content of organic matter and aquatic organisms is responsible for intense degradation processes which lead to depletion of oxygen.

New experiments were carried out on testing the biomass of thermophilic and acidophilic algae Galdieria sulphuraria for removal of toxic metals cadmium (Cd), copper (Cu), lead (Pb), and nickel (Ni) from the aquatic environment. After incubation of the biomass of these algae in an aqueous medium the concentrations of the metals (cadmium and others) decreased, more significantly for copper and lead than for cadmium and nickel. The results of the experiments were discussed from the perspective of efforts towards innovative biotechnologies (ecotechnologies) for water purification.

The interaction between inorganic pollutants and higher aquatic plants was studied. Experimental data demonstrated toxic effects from a mixture of heavy metals (Cu, Fe3+, Ni, Fe2+, Zn, Cr6+, Pb, Cd) on Chara fragilis and Callitriche palustris macrophyte species. The experiments were carried out in freshwater microcosms at temperature 12–19°C. Phytotoxicity of the tested mixtures of heavy metals to the macrophytes was revealed. Shoots of C. fragilis and C. palustris plants showed some common signs of phytotoxicity. The new results contribute to the development of water purification phytotechnologies, as well as to elucidation of the range of conditions for applicability of the investigated species in phytoremediation.

The dynamics of the nitrogen, carbon, and phosphorus contents in the detrital particles suspended in the water column was examined. The study was carried out in two freshwater reservoirs of different trophic levels. Detritus was collected in natural aquatic ecosystems at various depths. The nitrogen, phosphorus, and carbon concentrations in the detrital particles were found to decrease significantly during the detritus sedimentation in the water column. This pattern was observed both for a mesotrophic reservoir and an eutrophic aquatic ecosystem. It was the phosphorus concentration that decreased especially rapidly during the sedimentation of the detrital particles in the water column. These findings were considered in the context of water quality formation. The new facts and their analysis advance our understanding of the most important functions of detritus in aquatic ecosystems; a new aspect of coupling of ecological and biogeochemical processes in aquatic ecosystems was revealed. The results were analyzed using the innovative scientific term, exometabolism, which was proposed by S.A. Ostroumov in his monograph “Aquatic Organisms in Water Self- Purification” in 2008.

Three toxic metals-lead, copper and zinc - were measured in the biomass of the aquatic higher plants of Elodea densa. The method of atomic absorption spectrophotometry was used. Plants were incubated at elevated concentrations of three metals in the aqueous medium. This has led to a significant increase in lead content in plant biomass. Namely, the concentration of lead in biomass increased to 1567% compared to the background concentration of this element in the biomass in the control (the background concentration was taken as 100%). After incubation, the concentration of copper in the biomass was 594% of the background concentration. After similar incubation, zinc concentration was 133% of the background concentration. The results can be useful in the analysis of biological monitoring and water purification.

In this paper, we present the analysis of the ecological roles of detritus and suspended particulate matter in aquatic ecosystems. New data that have been obtained for freshwater ecosystems of the central part of Russian Federation (Moscow Region, e.g., Mozhaiskoe Reservoir) have been included in the analysis. These new data include the results of studies of samples of water and detritus from the aquatic ecosystems. The review analysis addresses both freshwater and marine ecosystems. The multifunctional important role of detritus in aquatic ecosystems has been shown and exemplified using data for aquatic bodies of different trophic level, from oligotrophic to eutrophic.