E. A. Trofimova

The first results of using the Allium test in estimating the chemical and radiation toxicity of bottom sediments in the Yenisei River

The first results of the use of the Allium test for estimation of toxicity of bottom sediments in the Yenisei River and the effect of external γ-radiation under laboratory conditions are presented. The effect of stimulation of the onion root growth, i.e., the absence of toxicity was discovered in toxicological experiments using bottom sediments and under external γ-radiation. The stimulating effect of radiation on the growth of onion roots limits the use of the Allium test for testing samples from the Yenisei River ecosystem in the zone subjected to the impact of radioactive discharges from the Mining and Chemical Combine.

Use of the aquatic plant Elodea canadensis to assess toxicity and genotoxicity of Yenisei River sediments

The toxicity, cytotoxicity, and genotoxicity of bulk sediments from the Yenisei River (Siberia, Russia) were estimated in laboratory bioassays based on several endpoints in the aquatic plant Elodea canadensis. The bottom sediment samples were collected in the Yenisei River upstream and downstream of the sources of chemical and radioactive contamination. The testing revealed different sensitivities of Elodea endpoints to the quality of the bottom sediment: weight of shoots < length of shoots < mitotic index < length of roots < percentage of abnormal cells. The response of the genotoxicity endpoint (percentage of cells with chromosome abnormalities in roots of Elodea) was the highest in sediments with chemical pollution, whereas the highest inhibition of toxicity endpoints (shoot and root length) occurred in sediments with the highest level of radioactive pollution. The extreme response of Elodea endpoints to the quality of certain sediment samples may be regarded as related to the possible presence of unknown toxicants. The results show that E. canadensis can be used as an indicator species in laboratory contact testing of bottom sediment. The responses of shoot and root length growth endpoints of Elodea can be recommended as basic sensitivity indicators of bottom sediment toxicity. Analysis of cells carrying abnormal chromosomes in the apical root meristem of Elodea can be performed optionally in the same test to assess the genotoxicity of sediments.

Chromosomal abnormalities in roots of aquatic plant Elodea canadensis as a tool for testing genotoxicity of bottom sediments

Submersed freshwater macrophytes are considered as relevant indicators for use in bulk bottom sediment contact tests. The purpose of this study was to estimate the validity of endpoints of aquatic plant Elodea canadensis for laboratory genotoxicity testing of natural bottom sediments. The inherent level of chromosome abnormalities (on artificial sediments) in roots of E. canadensis under laboratory conditions was lower than the percentage of abnormal cells in bulk sediments from the Yenisei River. The percentage of abnormal cells in roots of E. canadensis was more sensitive to the presence of genotoxic agents in laboratory contact tests than in the natural population of the plant. The spectra of chromosomal abnormalities that occur in roots of E. canadensis under natural conditions in the Yenisei River and in laboratory contact tests on the bulk bottom sediments from the Yenisei River were similar. Hence, chromosome abnormalities in roots of E. canadensis can be used as a relevant and sensitive genotoxicity endpoint in bottom sediment-contact tests.

Evaluation of cytogenetic abnormalities in cells of submerged plant Elodea canadensis in the Yenisei River section affected by industrial pollution: Field studies and laboratory experiments

27 The Yenisei River, one of the largest rivers in the world which, is exposed to radiation impact for at least 50 years because of the weapon grade plutonium pro duction in the Mining and Chemical Plant (MCP) of Rosatom in Zheleznogorsk [1–4]. Bottom sediments and floodplain of the Yenisei River are polluted with artificial radionuclides, including transuranic ones, not only in the vicinity of MCP, but also at a consider able distance downstream the river. During operation of MCP nuclear reactors, at least 20 of the anthropo genic radionuclide typical of MCP outlets were inden tified in biomass on the Yenisei submerged macro phytes [2]. Elodea canadensis Michx belongs to mass macrophyte species vegetating in zones of anthropo genic pollution and on the background areas [5]. Pre vious studies suggest that, in the Yenisei area contam inated with radionuclides, cytogenetic abnormalities in the elodea root cells were more frequent than in similar plants vegetating in the Yenisei section above MCP outlets [6]. Cytogenetic damages of the plant root meristem serve as indicators of cyto and geno toxicity in assessing the environmental quality [7, 8].

Estimation of transfer of technogenic radionuclides in food chains of the Yenisei river

The efficiency of the transfer of gamma-emitting radionuclides in food chains, including macrophytes, zoobenthos, and bentho- and ichthyophagist fish, was estimated in the radiation-polluted region of the Yenisei river. Significant differences in the efficiency of the transfer of natural and technogenic radionuclides between components of different trophic levels were revealed. Substantial species-related differences in the accumulation of radionuclides in ichthyophagist fish from food were revealed.

Bioaccumulation, inter-organ distribution, and retention of waterborne and dietary 241Am in silver crucian carp

The bioaccumulation of actinide 241Am from food and water in bodies of freshwater fish (Carassius auratus gibelio, silver crucian carp) has been investigated in laboratory experiments. Homogenized biomass of submerged macrophytes labeled with 241Am was injected into the fish gullet. Internal organs and tissues of crucian carp could be ranked according to activity concentration of dietary 241Am after depuration of the digestive tract as follows: liver > gonads > bones > muscles. Accumulation of waterborne 241Am in internal organs and tissues of crucian carp mainly occurred via the digestive tract. While the concentration of 241Am in liver of crucian carps decreased during depuration time, its concentration in bones increased indicating slower transfer of 241Am to skeleton compared to muscles and liver. The retention of dietary 241Am in the bodies of crucian carp reached 35%–46% of ingested 241Am: 20%–31% was retained in liver, 0.6%–0.8% in skeleton, and 1.4%–2.0% in muscles. The concentration factor of 241Am from water was 0.4 for the whole body, 0.3 for liver, 0.01 for muscles, and 0.01 for skeleton. Trace amounts of 241Am were recorded in viscera and muscles of a wild population of silver crucian carp inhabiting a radioactively contaminated part of the Yenisei River.

New data on the effect of ionizing radiation on the growth of the aquatic plant Elodea canadensis in the laboratory

Toxicological experiments with radioactive bottom sediments and extrinsic γ-irradiation have demonstrated that the growth of common elodea roots is suppressed by irradiation at doses several times lower than the established threshold dose. The effect of γ-irradiation on the growth of elodea stems has not been observed at any dose used. The data obtained show that elodea could be recommended for use as an indicator of biological effects of radiation in the range of low radiation doses.

Experimental estimation of the possible use of submersed macrophytes for biotesting bottom sediments of the Yenisei River

The laboratory testing of bottom sediments (BSs) from the Yenisei River containing different concentrations of technogenic radionuclides, heavy metals, and biogenic elements (N and P) based on aquatic such plants as Elodea canadensis (Canadian waterweed) and Myriophyllum spicatum (Eurasian watermilfoil) has revealed a higher sensitivity of roots to the general quality of BSs than shoots: shoot length (9%) < root length (11%) < root number (15%) in M. spicatum; shoot length (22%) < root length (42%) < root number (44%) in E. canadensis. In contrast to M. spicatum, the growth parameters of roots and shoots in E. canadensis have differed in a significant statistical manner between most BS samples. A reverse correlation has been found between the increase in shoot length and the activity of technogenic radionuclides in BSs, which is mostly significant in E. canadensis (r2 = 0.90–0.95, p = 0.05). Since the growth of shoots and roots in E. canadensis has turned out to be more sensitive to changes in the quality of BSs than that in M. spicatum, E. canadensis can be considered more prospective for biotesting BSs.

UNESCO WORLD KARST NATURAL HERITAGE SITES: GEOGRAPHICAL AND GEOLOGICAL REVIEW

The paper is devoted to the review of the World Karst Natural Heritage and the perspectives of such new properties in the Russia. Presently there are 37 World Karst Natural Heritage sites on the globe; 34 of them have the natural heritage and 3 sites have the mixed, natural-cultural significance. The World Karst Heritage distribution by the countries and by parts of the world was analyzed. A brief description of outstanding universal value of the “Lena Pillars Nature Park”, being currently the only Russian karst area nominated at the List of World Natural Heritage by a specific type of the karst – ground frozen karst, was given. The necessity of the new World Karst Heritage properties characterizing by the karst development in sulfate and salt rock sites are considered. The karst areas, located in extreme (cold or arid) climate conditions, are in the focus of separate attention.

Seasonal changes in feeding and relative condition factors of Arctic grayling (Thymallus arcticus) in a stretch of the middle reaches of the Yenisei River

The seasonal dynamics of feeding spectra and diet of Arctic graying in a stretch of the middle reaches of the Yenisei River (from the dam of the Krasnoyarsk HPP to the mouth of the Kan River) was studied in 2009–2013. Its connection with the food-supply state and fish growth has been traced. It has been shown that the intensity of fish feeding is relatively stable throughout the year, despite significant fluctuations in zoobenthos biomass. The contribution of groups dominating in diet (amphipods and larvae of caddisflies) changes depending on the month. Amphipods prevail in the diet of fish during the period from June to October and caddisflies prevail in the winter and spring months. Among caddisflies, selective feeding on a small species, Apatania crymophila, has been revealed. The change of the primary diet component during the summer period corresponds to a sharp increase in the coefficients of relative condition factors with a peak in August–September. It has been assumed that changes in the ratio of weight and linear sizes of fish are associated not only with an increase in the water temperature, but also with the grayling switching to the consumption of amphipods with a higher nutrition value.