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1

Intraspecific Sensitivity to Toxicants – a Methodological Problem of Bioassay: Review

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Olkova A.

Journal of Ecological Engineering

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2021

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tom Vol. 22, nr 7

113--122

EN

The article discusses the scientific studies that reveal the mechanisms of intraspecific differences in responses of organisms to chemical exposure. The factors of individual sensitivity to toxicants are represented by genetic differences between individuals of the same species and genetically unconditioned factors. The genetic factors are mutations, including under-researched mitochondrial DNA mutations and genomic drift, genetic polymorphism, and gender-related differences. Age, conditions of keeping and state of organisms, seasonal variations of body functions, and biotic interactions are considered as the factors that are not related to the genetic apparatus. The article considers a number of works, in which the effects of the combined action of external factors on sensitivity of organisms in model groups are studied.

2

Toxicity of Water after Short-Term Contact with PVC Materials Depending on the Temperature and Components of the Polymer Composition

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Olkova A.

Ecological Engineering & Environmental Technology

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2021

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tom Vol. 22, iss. 5

119--125

EN

This work shows a paradoxical fact: a highly plasticized PVC sample containing the maximum amount of the plasticizer di(2-ethylhexyl) phthalate (DEHP) compared to medium- and low-plasticized polymers turned out to be the least toxic. This was confirmed in express bioassays for the pre-lethal reactions of Paramecium caudatum Ehrenber and Escherichia coli M-17 when determining the acute toxicity for mortality of Daphnia magna Straus and Ceriodaphnia affinis Lilljeborg, as well as in chronic tests for D. magna. The migration of DEHP from the tested PVC samples into water was confirmed by the mass spectrometry method. It was shown that the contact of PVC materials with hot water (70℃) led to a significant increase in the toxicity of the extracts compared to cold extraction (20℃). The search for safe composition of PVC materials must be carried out in the direction of the optimal ratio of PVC-polymer, plasticizer and heat stabilizer, as well as replacing the components of the composition with safe substances.

3

Targeted Selecting of Bioassay Methods as an Alternative to the "Battery of Bioassays"

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Olkova A.

Ecological Engineering & Environmental Technology

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2022

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tom Vol. 23, iss. 2

153--161

EN

The article describes an algorithm for selecting a targeted bioassay method. It was proposed to consider the most sensitive method to a certain contamination as the targeted method of bioassay. The selection was made from a "battery of bioassays", which necessarily includes the D. magna mortality test. The rest of the methods for comparing sensitivity were selected situationally. The algorithm was tested on model samples. It was found that mortality tests for D. magna and C. affinis are the most sensitive to contamination with mineral nitrogen compounds. E. coli bioluminescence reduction test is preferred when there is contamination with Cu, phosphates and pyrophosphates. It was shown that the test to reduce the chemotactic reaction of P. caudatum should be used when the aquatic environment is polluted with Cd, Pb, Zn, oil products, organic herbicides imazethapyr and imazamox. The proposed algorithm is universal, but it should be applied when the priority pollutant is known, the effects of which prevail over the action of other compounds in the sample.

4

Transformation of Urbanozems in the Areas of Gas Stations

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Olkova A. , Zimonina N.

Ecological Engineering & Environmental Technology

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2021

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tom Vol. 22, iss. 3

51--58

EN

The areas near gas stations are places of local specific environmental pollution. The purpose of this work was to study the environmental consequences of gas station functioning on the surrounding soils (urbanozems). The content of oil products (OP), bulk and mobile forms of heavy metals, acute toxicity (Ceriodaphnia affinis Lillieborg, Раramecium caudatum Ehrenberg, Escherichia coli Migula), chronic toxicity (C. affinis), and the state of soil microphotrophs were determined. The content of OP was from 520±130 to 4820±100 mg/kg, which is significantly higher than the concentrations of OP in the soils of the transport zone of cities. The exceeding of the Russian standards for HM was found only for zinc (the maximum for the total form – 1.7 MPC, for the mobile form – 1.4 MPC). The urbanozems samples did not have acute toxicity; however, chronic toxicity in the bioassay for the mortality of C. affinis (up to 85%) and a decrease in the fertility of crustaceans (2–3 times compared to the control) were observed. In the structure of the community of soil microphototrophs, cyanobacteria dominated both in biomass and in abundance: (up to 748±10 thousand cells/1 g of soil) compared with green algae and diatoms (1.1–5.5 and 1.2–19.8 thousand cells/1 g of soil, respectively). As a result of the work, it was concluded that the quantitative algological analysis and biotest with the assessment of chronic toxicity in terms of mortality and fertility of C affinis for the diagnosis of local soil contamination in the areas of gas stations were of the highest informative value.

5

Assessment of the Toxicity of the Natural and Technogenic Environment for Motor Activity of Daphnia magna

63%

Olkova A. , Zimonina N.

Journal of Ecological Engineering

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2020

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tom Vol. 21, nr 7

11--16

EN

The Daphnia magna Straus (1820) crustaceans are used in many countries to assess the quality of the environment. Researchers are guided more often by the mortality of individuals. However, the sublethal effects contribute to the development of biological early warning systems (BEWS). A visual method for recording the motor activity of D. magna was proposed. This method has advantages over automated analogs. It is simple, accessible to performers and does not require the use of special instruments. The method was tested under conditions of modeling the lethal and sublethal effects of heavy metal salts (Cu and Zn). The diagnosis of lethal doses is possible after 1 hour of exposure, whereas the death of crustaceans can occur in 3–4 days of the experiment. The effect of sublethal doses of heavy metals becomes statistically significant after 24 (p < 0.05). The sensitivity of the method was confirmed in the studies of the aqueous extracts from the soils contaminated with various heavy metals (heavy metal processing area). The method showed good results in assessing the toxic effect of the waters anthropogenically contaminated with the mineral forms of nitrogen (NH4+and NO3-) in the region of fertilizer production. The maximum inverse correlation between the motor activity and the concentration of ammonium ions in water (-0.83) was shown after 24 hours. Thus, the method of visual assessment of motor activity can be used in environmental monitoring.

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"Battery of Bioassays" for Diagnostics of Toxicity of Natural Water when Pollution with Aluminum Compounds

63%

Olkova A. , Berezin G.

Journal of Ecological Engineering

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2021

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tom Vol. 22, nr 2

195--199

EN

The article presents the results of an experimental comparison of the sensitivity of biotests using Daphnia magna Straus, Ceriodaphnia affinis Lilljeborg, Paramecium caudatum Ehrenberg, and Escherichia coli Migula (strain M-17) to water pollution with aluminum compounds. The research was carried out under simulated conditions: the model toxicant was aluminum sulfate Al2(SO4)3∙18H2O, the concentration range per Al was 0.04–2.8 mg/dm3, and the pH of the tested waters was close to the neutral level of 7.2–7.8. The bioluminescence of E. coli significantly decreased at an Al concentration of 0.8 mg/dm3 (toxicity index was 93.3±1.2, which refers to a high level of toxicity). The reaction of P. caudatum was weaker: a high level of toxicity was achieved at an Al concentration of 2.8 mg/dm3. These doses did not cause the death of D. magna and C. affinis in short-term experiments (28 and 96 hours, respectively). However, in the tests for the chronic toxicity of aluminum, we showed that the doses of 0.8 and 2 mg/dm3 Al cause high death of individuals (more than 50%) and a significant decrease in the number of offspring. The range of sensitivity of the bioassay methods to water pollution with aluminum turned out to be as follows: bioassay for the bioluminescence of E. coli > bioassay for the changes in chemotaxis of P. caudatum > bioassay for the changes in fertility of D. magna > bioassay for the changes in fertility of C affinis.