International Letters of Natural Sciences Vol. 70

Abstract: It has been investigated the ecological status of the cooling pond of Zaporizhzhya Nuclear Power Plant (NPP) on the hydrochemical and toxicological indicators. The ecological water quality by most hydrochemical and hydrophysical indices corresponds to the class II, category 3, and is characterized as "fairly clean". However, according to the BOD₅ index, the water quality is "satisfactory" (class III, category 4). By the contents of both nitrogen of nitrates and phosphorus of phosphates the water quality belongs to the class IV, category 6, as "bad, dirty water". The main anthropogenic pollutants are copper, iron, zinc, and fluorides. The ecological characteristics by their concentrations in the water correspond to the class III, and categories 4–5 of quality, which are "poorly and moderately polluted" water. Accumulation of toxic metals in the surface layer of the reservoir bottom sediments depends on their types, the minimal content is found in sandy sediments, and maximal one is in muddy sediments. The possibility of significant secondary pollution of the water environment by toxic metals is small under the hydrophysical and hydrochemical conditions typical for the cooling pond of Zaporizhzhya NPP. According to the calculations, the value of the average chemical index of ecological quality is "2.5", which characterizes the water of the Zaporizhzhya NPP cooling pond as "good" and "clean".

Abstract: In the experiment with marbled crayfish Procambarus virginalis (Lyko, 2017), chronic effects of various concentrations of heavy metal ions on the physiological state and enzyme activity were investigated. The obtained results showed that among the investigated heavy metals nickel ions influenced the weight indexes and mortality of crustaceans the most negatively. According to the results of the research, significant changes were noted in the individual biochemical parameters of marbled crayfish under the influence of manganese, lead and nickel ions. The most significant changes in the activity of lactate dehydrogenase were detected in muscle tissues affected by manganese and nickel ions. A significant decrease in the activity of succinate dehydrogenase in muscle of marbled crayfish was determined after the action of heavy metal ions. Investigation of changes in the activity of alkaline phosphatase under the influence of the ions of manganese, lead and nickel has its own characteristics, which indicates certain violations in the tissues of cell membranes. Changes in the activity of enzymes were also reflected in the overall protein content. Changes in these parameters may indicate a rapid biochemical response of crustaceans to the toxic effects of heavy metals.

Abstract: Manganese, lead and nickel are heavy metals, which are the priority fresh water toxic contaminants and relate to of the first danger class chemicals. Heavy metals cause functional disorders in the tissues and organs of hydrobionts, affecting their linear and weight indices, reproductive system, digestive and extraction organs. In the experiment on marbled crayfish Procambarus virginalis (Lyko, 2017) studied the long-term effects of various concentrations of heavy metal ions on the physiological state and histostructure of tissues and organs. According to the results of research, it was found that among the studied heavy metals nickel ions influenced the weight indexes and mortality of crustaceans the most negatively. The results of morphometric studies on marbled crayfish indicate no significant changes in the control group and experimental one, but heavy metals influenced the form of the hepatopancerase lobes and the size of the lumen of the gland. Research on adipocytes of the connective tissue showed a significant difference between the size of cells under the influence of heavy metals. Dimensions of adipocytes fluctuated in a wide range from 144 μm² to 537 μm². In control group the adipocyte area was 406.96 μm². Experimental studies of hemolymph showed that, under the influence of lead ions, a significant increase in 1.4 times was observed in the area of hemolymph cells; when manganese and nickel were added, moderate decrease was observed in cells. It was found that under the influence of nickel, the area of round hyalinocytes has reduced by 1.7 times.

Abstract: Problem of biofilm formation have a great significance for environmental microbiological research. Biospheric microorganisms can form biofilm, that provide bacteria resistance to influence of different environmental factors. Some of the most common bacteria in biosphere are bacilli, among them there are film-forming strains. Bacillus spp. ia a well-known film forming microorganisms that colonize environmental objects. The biofilm fouling of underwater elements of small wooden constructions located on the Dnieper River near the city of the Dnipro (Ukraine) was studied. It was found that biofilms from surfaces of water constructions include bacilli. It is established that the mean values of CFU in samples from running and still water were (1.81±0.52)×10⁸ and (1.83±0.53)×10⁸ CFU / ml respectively per area of wooden sample approximately 1 cm², while during the laboratory cultivation of the film, formed by these cultures on the plate, the number of cells was (4.90±0.93)×10⁷ and (4.60±1.07)×10⁷ CFU / ml per 1 cm² of the well’s bottom, which was an approximate limit of the content of cells of the Bacillus spp. film per unit of area.