Seasonal Dynamics of the Structure of Intestinal Helminth Community in Ide (Leuciscus idus L.) from the Rybinsk Reservoir

The communities of intestinal helminths found in the winter sample of ide (December–May, 45 fish) and in the summer sample (August–September, 42 fish) were compared. They consisted of 10 and 11 species, respectively, with Sphaerostomum globiporum being dominant in both communities. The species Parasymphylodora markewitschi and Capillaria tomentosa were found only in the summer community. Dominance and diversity (the Simpson and Brillouin indices) in the winter community were higher. All helminth species in the intestinal community of ide were of broad specificity. Therefore, host specialization does not play an important role in the forming of intestinal helminth community in this fish species.     

The Phenomenon of Pseudoviviparity in Alpine and Arctomontane Grasses (DeschampsiaBeauv., FestucaL., and PoaL.)

It is known that pseudoviviparous plant taxa are most numerous in the Arctic and high mountain regions, where they sometimes account for a noticeable part of the local flora and play an important phytocenotic role. The complex of pseudoviviparous taxa is an interesting model for investigating the processes of hybridogenic speciation, as various mechanisms stabilizing the hybrid genetic systems proved to be effective in them. In particular, this concerns vast and taxonomically complex groups such as the genera Deschampsia, Festuca, and Poa.In this paper, published data on the taxonomy, chromosome numbers, and distribution of pseudoviviparous grasses in the Arctic regions and subarctic mountain systems are reviewed.     

Toxicity of copper in sewage sludge

Sewage sludge is a source of organic matter and nutrients, but a major obstacle for its recycling is that the municipal wastewater sludge has low but significant levels of contaminants. This investigation, on the acute toxicity of copper in sewage sludge, was conducted with three organisms, Daphnia magna, Lemna minor and Raphanus sativus (seeds). The toxicity of the leakage water from sewage sludge spiked with CuSO(4) was studied for 64 days. The toxicity increased during the first 8-16 days and then started to decrease. The first increase in toxicity was due to ammonia, but after 32 days, a dose-related effect of copper was found. After 64 days, L. minor had an EC50 of 3800 mg Cu/kg dw for 7 days growth inhibition, a LOEC of 3200 mg Cu/kg dw and a NOEC of 1600 mg Cu/kg dw. D. magna had an EC50 of 18100 mg Cu/kg dw (24-h immobility) and a NOEC of 12800 mg Cu/kg dw. Root elongation of R. sativus was reduced at 25600 mg Cu/kg dw. Both for Daphnia and Lemna, the pH of the leakage water had an effect of the toxicity. This means that chemical speciation and bioavailability is very important for the hazard assessment of copper in sludge and soil.     

Activity of glutathione S-transferase in Spodoptera exigua larvae exposed to cadmium and zinc in two subsequent generations

The aim of our study was to establish changes in activity of important in detoxification enzyme-glutathione S-transferase (GST): in alimentary tract, fat body and Malpighian tubules of Spodoptera exigua larvae being under cadmium and zinc exposure through the first as well as the second generation. There was registered enhancement of the enzyme activity in the fat body and the Malpighian tubules caused by zinc as well as its decrease in the Malpighian tubules under cadmium action. Amounts of metals in the alimentary tract were either several times higher than in the diet ingested by larvae or than in the fat body. Metal concentration in the fat body correlated with the level of the enzyme activity (positive correlation for zinc and negative for cadmium). The effect of metal action differentiated dependently on time exposition.     

Acute and sub-lethal toxicity of landfill leachate towards two aquatic macro-invertebrates: demonstrating the remediation potential of air stripping

A specific leachate that contained 1.036 mg l(-1) of 2-chlorobiphenyl was used in the study (255 mg l(-1) COD and 133 mg l(-1) BOD5). Bench scale (20 l) air stripping trials were used to simulate on a small-scale the treatment potential of this method. Air stripping effectively reduced the leachates COD concentration. Regardless of the volume of air supplied (1-5 l of air per minute) the leachates COD reached a <50 mg l(-1) equilibrium after 96-h exposure, however, increasing the volume of air accelerated the process. In untreated leachate, the LC50 for Asellus aquaticus was 57% v/v leachate in deionised water and 5% for Gammarus pulex (96-h, static LC50 tests without nutrition and oxygen depleting conditions). After being exposed to air stripping, these values rose from 90% to below the LC50 threshold for Asellus when 1-5 l of air per minute were applied and 30-90% for Gammarus. Furthermore, in sub-lethal concentrations of air stripped leachate (leachate that had been exposed to 5-l of air per minute for 96-h) the population dynamics of both test species remained unaltered.     

Experience in using ecological phytoindication scales for revealing unfavorable factors at the boundary of species distribution

The ecological phytoindication scales proposed by Tsyganov (1983) were used for characterizing biotopes at the northern limit of the distribution of three nemoral species:Ajuga reptans, Asarum europaeum, andPulmonaria obscura. Regional ecological amplitudes of the model species were determined. The environmental factors approaching the lower limit of species amplitudes in Tsyganov's scales were classified as unfavorable.     

Toxicities and tolerances of Cd, Cu, Pb and Zn in a primary producer (Isochrysis galbana) and in a primary consumer (Perna viridis)

Studies on toxicities and tolerances of cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) in the brown alga Isochrysis galbana and in the green-lipped mussel Perna viridis were conducted by short-term bioassays using endpoints growth production and mortality, respectively. The 5-day EC(50) and 24-h LC(50) of these heavy metals were determined in the brown alga and mussel, respectively. The EC(50) values calculated for the alga were 0.74 mg/l for Cd, 0.91 mg/l for Cu, 1.40 mg/l for Pb and 0.60 mg/l for Zn. The LC(50) values for the mussels were 1.53 mg/l for Cd, 0.25 mg/l for Cu, 4.12 mg/l for Pb and 3.20 mg/l for Zn. These LC(50) values were within the concentration ranges as reported by other authors who used P. viridis as the test organism. Based on these EC(50) and LC(50) values, the alga was most sensitive to Zn, followed by Cd, Cu and Pb while the mussel was most sensitive to Cu, followed by Cd, Zn and Pb. Differences in the trophic levels, metal handling strategies, biology and ecology of the primary producer (brown alga) and the primary consumer (mussel) are believed to be the plausible causes for the different toxicities and tolerances of the metals studied.     

Effects of the Bacterial Component on the Viability of the Paramecium bursariaSymbiotic Complex (Infusorian–Zoochlorella)

A hypothesis is considered that the establishment and maintenance of mass exchange processes in the Paramecium bursariasymbiotic complex (infusorian–alga) depends on the presence of the third component—bacteria—whose role is underestimated but essential for completing the exchange cycle. The role of this component in the symbiotic cycle of Paramecium bursariais possible to reveal using special bactericidal preparations specifically inhibiting the bacteria involved in the metabolic cycle but having no effect on the functions of the host cell and the zoochlorella population. Experiments with various preparations of this type were performed, and the response to treatment was estimated from growth rates of the symbiotic complex and its components. This allowed identification of an antibiotic (rifampicin) that had no adverse influence on free-living zoochlorella and chlorella-free paramecia (the basic components of the symbiotic cycle) but drastically inhibited the growth of the P. bursariasymbiotic complex, which could be interpreted as evidence in favor of the hypothesis concerning the existence of the third symbiotic component.     

Biotopic Variation and Phenogeography of Dreissena polymorpha (Pallas)

The phenetic structure of Dreissena polymorpha populations in different water bodies is considered. The phenotypes of shell pattern and sculpture are identified and described using a scheme based on elementary characters, or pattern elements. It is shown that the frequencies of phenes in mollusks from different biotopes of the cooling system of two thermal power plants differ significantly. The data on species phenogeography are reviewed.     

Proliferative Activity of Corneal Epithelium and Specific Features of Morphogenesis in Postmetamorphic Rana arvalisNilss. in Urbanized Areas

The mitotic activity and sizes of corneal epithelial cells in postmetamorphic Rana arvaliswere studied in the populations exposed to different degrees of anthropogenic impact in the city of Yekaterinburg. The studies were conducted at the initial stages of frogs' terrestrial life in three consecutive years. Mitotic activity exhibited a slight positive correlation with the liver index, which indirectly reflects the general metabolic rate in young frogs. The combined estimation of proliferative activity, epithelial cell size, and relative liver weight had the highest information value. There was a relationship between the mitotic index and liver index in young frogs from habitats with the highest level of anthropogenic transformation. This indicates that morphogenesis is well-balanced and is likely to decrease the probability of morphological abnormalities in frogs developing in the unstable environment. This physiological property allows the populations to exist and reproduce in urbanized areas.     

Bioaccumulation of chlorinated pesticides and PCBs in the tropical freshwater fish Hoplias malabaricus: histopathological, physiological, and immunological findings

For assessing the impact of chlorinated compounds, such as organochlorine pesticides, polychlorinated biphenyls, chlorotriazines (atrazine, simazine), and chlorinated phenylureas (diuron), on the Ponta Grossa lake South of Brazil, ten freshwater trahira fish (Hoplias malabaricus) were collected in October 2005. The contamination status was evaluated by the energy budget and various histopathological markers. The results showed detectable amounts of persistent organic pollutants (POPs) in the liver and muscle; the bioaccumulation was higher in the liver than in the muscle. The presence of some banned pesticides, such as hexachlorobenzene and dichlorodiphenyltrichloroethane, in the liver suggests an acute exposure to these compounds. Some physiological disturbances and morphological damages found in the liver of H. malabaricus were associated with chlorinated-compound bioaccumulation. The most important alterations in the liver were lesions such as fibrosis, large necrosis area, leukocyte infiltration, and the absence of melanomacrophages (MM). Individuals containing higher concentrations of pesticides, such as aldrin, alachlor, and dichloroaniline (a metabolite of diuron), showed the nonoccurrence of MM in the liver. These data suggest an immunosuppression in the individuals from Ponta Grossa Lake after exposure to POPs. According to the present data, the POPs found in the studied site are bioavailable, induce severe damages in target organs such as the liver, and can disturb the immune system of the trahira. This is the first study of POPs in the Paraná state, and one among the few studies in the south of Brazil. The present data suggest and motivate further chemical and biomonitoring studies in freshwater ecosystems in the south of Brazil.     

Metal and metallothionein level in the heat-treated cytosol of gills of transplanted mussels Mytilus galloprovincialis Lmk

A stock of mussels Mytilus galloprovincialis was transplanted over 1 year to four sites in a semi-enclosed bay in Croatia which is under the influence of various sources of pollution. The positive correlation of metal (Cd, Zn, Cu, Mn, Fe) and metallothionein (MT) tissue contents based on the analysis of heat-treated cytosol of gills with shell mass, as an indicator of mussel age, indicated to accumulation of metals, as well as the increase of MTs with mussel age. The principal component analysis (PCA) revealed that 74% of total variance of obtained results could be explained through two principal components. The first principal component was highly correlated with MT, Cd and Zn indices (metal or MT content/shell mass), and the second one with Cu, Mn, and Fe indices, as well as the gill index. High correlation of MTs with Zn and Cd is consistent with their affinity for binding to MTs.     

Development of a Test System for Assessing the Toxicity of Multicomponent Wastes Stored in the Natural Environment

A biological test system is proposed for assessing the toxicity of multicomponent wastes stored in the natural environment, with sewage sludge being used as an example. The principles of creating a test system and ranking the samples of multicomponent masses with respect to environmental hazard are discussed.     

The ecology of bilberry (Vaccinium myrtillus L.) and cowberry (Vaccinium vitis-idaea L.) in Western Siberia

The data on the ecology of bilberry and cowberry in the West Siberian Plain, Kuznetsk Ala Tau, and highland Altai are presented. Ecological ranges of these plants and amplitudes of their tolerance for some environmental factors are described.     

A commentary on recent water safety initiatives in the context of water utility risk management

Over the last decade, suppliers of drinking water have recognised the limitations of relying solely on end-product monitoring to ensure safe water quality and have sought to reinforce their approach by adopting preventative strategies where risks are proactively identified, assessed and managed. This is leading to the development of water safety plans; structured 'route maps' for managing risks to water supply, from catchment to consumer taps. This paper reviews the Hazard Analysis and Critical Control Point (HACCP) procedure on which many water safety plans are based and considers its appropriateness in the context of drinking water risk management. We examine water safety plans in a broad context, looking at a variety of monitoring, optimisation and risk management initiatives that can be taken to improve drinking water safety. These are cross-compared using a simple framework that facilitates an integrated approach to water safety. Finally, we look at how risk management practices are being integrated across water companies and how this is likely to affect the future development of water safety plans.     

On adaptations of trees and shrubs in the north of the Russian Far East

Specific ecological features of trees (Chosenia arbutifolia and Betula lanata) and shrubs (Pinus pumila and Duschekia fruticosa) at the northern limit of their distribution are compared. New biomorphological adaptations of these species under extreme conditions are described.     

Environmental risk assessment of metals: tools for incorporating bioavailability

In this paper, some of the main processes and parameters which affect metal bioavailability and toxicity in the aquatic environment and its implications for metal risk assessment procedures will be discussed. It has become clear that, besides chemical processes (speciation, complexation), attention should also be given to physiological aspects for predicting metal toxicity. The development of biotic ligand models (BLMs), which combine speciation models with more biologically oriented models (e.g. GSIM), has offered an answer to this need. The various BLMs which have been developed and/or refined for a number of metals (e.g. Cu, Ag, Zn) and species (algae, crustaceans, fish) are discussed here. Finally, the potential of the BLM approach is illustrated through a theoretical exercise in which chronic zinc toxicity to Daphnia magna is predicted in three regions, taking the physico-chemical characteristics of these areas into account.     

Structure and formation of conifer stands in the upper timberline ecotone on the North Chuya Ridge,Central Altai

The structure of Siberian stone pine (Pinus sibirica Du Tour.) and Siberian larch (Larix sibirica Ledeb.) stands and specific features of their formation have been studies in the forest-tundra ecotone on the North Chuya Ridge (2235–2475 m a.s.l.). Changes in the structure of these stands along the transition from the upper boundary of closed forests to the high-mountain tundra have proved to have an ambiguous pattern. Both tree species form mixed clusters of similar-aged trees in the lower part of the ecotone but grow singly, in scatters, in its upper part. The formation of conifer stands (tree clusters) in the lower part of the ecotone, on the slopes of the Aktru River valley, began during climate warming in the second half of the 19th century. The expansion of confers to its upper part took place markedly later, in the early 20th century (Siberian larch) or even in the 1930s (Siberian stone pine).