RADIATION SAFETY ASSESSMENT OF CARROT AND BEET PRODUCTS CULTIVATED IN THE BLACK EARTH ZONE OF RUSSIA IN THE OREOL OF THE EASTERN CHERNOBYL TRACE

On the territory of the Plavsky radioactive hotspot of the Tula region of Russia, formed as a result of the accident at the Chernobyl nuclear power plant in 1986, an assessment of the radiation safety of growing carrots and beets was carried out in 2019. It has been established that at present the content of 137Cs in arable leached chernozems of the surveyed lands is 90–170 kBq/m2 , which is 2.5–4.5 times higher than the permissible level of density of surface radioactive contamination of soils. However, the specific activity of the radionuclide in carrot and beetroot crops does not exceed 5 Bq/kg, which is significantly less than the maximum permissible level of 137Cs accumulation in vegetables (600 Bq/kg for absolutely dry weight). The accumulation coefficients of 137Cs in the total biomass of carrots and beets are 2.0·10−2 and 7.5·10−2, and in eaten root crops – 1.1·10−2 and 2.0·10−2, respectively, which is in good agreement with the IAEA estimate for the intensity of the transition 137Cs in the production of vegetable roots from loamy and clayey soils.

Accumulation of Tetrahymena pyriformis on Interfaces

The behavior of ciliates has been studied for many years through environmental biology and the ethology of microorganisms, and recent hydrodynamic studies of microswimmers have greatly advanced our understanding of the behavioral dynamics at the single-cell level. However, the association between single-cell dynamics captured by microscopic observation and pattern dynamics obtained by macroscopic observation is not always obvious. Hence, to bridge the gap between the two, there is a need for experimental results on swarming dynamics at the mesoscopic scale. In this study, we investigated the spatial population dynamics of the ciliate, Tetrahymena pyriformis, based on quantitative data analysis. We combined the image processing of 3D micrographs and machine learning to obtain the positional data of individual cells of T. pyriformis and examined their statistical properties based on spatio-temporal data. According to the 3D spatial distribution of cells and their temporal evolution, cells accumulated both on the solid wall at the bottom surface and underneath the air–liquid interface at the top. Furthermore, we quantitatively clarified the difference in accumulation levels between the bulk and the interface by creating a simple behavioral model that incorporated quantitative accumulation coefficients in its solution. The accumulation coefficients can be compared under different conditions and between different species.

Valorization of rare earth processing byproducts for agriculture usage

Sandy texture soil, a major problem for agriculture requires structure and capacity improvements. However, utilization of soil conditioner may arrest this problem. This research was carried out to investigate the accumulated levels of metal ions and radionuclides in water, soil and plants following phosphogypsum organic (PG organic) added to a sandy soil for 23-month in 3 cropping seasons. The condition in the field was simulated in the laboratory using an open leaching column for 30-day under constant but different pH of leachant. More ions were released at pH < 4.6 and decreases greatly at pH > 5.6. The metal ions measured in the surface and borehole water, and soils were below the target values for respective standard raw drinking water. The metal ions did not accumulate in soil, plant and grain, and water as indicated by biological accumulation coefficients, contamination factors, I-geo index and pollution load index in a sandy soil that received the PG organic. Naturally occurring radionuclide concentrations, such as 226Ra, 228Ra, and 40K, in soil and plant tissue were found to be lower than the average value reported by several earlier studies. Under field condition the pH of water (i.e., rainfall) was greater than pH 5.6, thus renders PG organic became less soluble. There was no leaching of natural occurring radionuclides to the groundwater. Therefore, the application of PG organic to the studied soil had no impact on the soil, plants, and water and suitable as a soil conditioner in sandy texture soils.

Pharmaceuticals in the Soil and Plant Environment: a Review

Pharmaceuticals are a class of biologically active compounds used in human and veterinary medicine, while some of them may be applied for feed production and plant growth stimulation. To systemise the knowledge on pharmaceuticals in plant and soil environment, a literature review was performed. Active substances of pharmaceuticals and their metabolites are typically released into the environment through agricultural application of wastewater and sewage biosolids containing pharmaceuticals, derived from wastewater discharged by households, hospitals and other medical facilities. Another, no less important, source of pharmaceutical release are natural fertilisers (manure and slurry). The fate and behaviour of pharmaceuticals in the soil, including their mobility and availability to plants, depends on the soil physical, chemical and biological properties as well as on the properties of the substance itself. Pharmaceuticals introduced into the soil are taken up and retained in various plant parts. In general, the highest accumulation coefficients have been found in vegetative plant parts, in the following decreasing order: roots> leaves> stems, while the lowest in generative parts, such as grains of cereals.

Growing miscanthus on radioactively contaminated soils and regularities of 137 CS redistribution in the system «Soil-Plant-Lysimetric waters»

Purpose. Investigate the patterns of transition of 137 Cs radionuclide from soil to biomass and lysimetric waters depending on the elements of technology for growing giant miscanthus on solid fuel on contaminated soils. Methods. Lysimetric, biomorphological, radiometric, statistical, comparative and computational. Results. The article presents the results of research to study the accumulation of the radioactive isotope 137 Cs in the biomass of giant miscanthus and its transition into lysimetric waters. According to the research results, the level of 137 Cs radionuclide accumulation in miscanthus plants on contaminated soils depends on its concentration in the soil and elements of cultivation technology. It was found that in the variants where the bioenergy crop was grown on soils contaminated with radionuclides, the accumulation of 137 Cs in the biomass in the range of 14.7–18.6 Bq/kg and in the lysimetric waters of 4.36–4.57 Bq/l was observed, respectively. Fertilization with mineral fertilizers together with defecation and treatment with miscanthus rice before planting with the microbial preparation Polymyxobacterin in combination with BioMAG helped to increase the yield of dry biomass by 28% of control. Conclusions. The use of mineral fertilization in combination with liming, inoculation of miscanthus rhizomes with the microbial drug Polymyxobacterin and pre-planting treatment with organo-mineral fertilizer BioMAG significantly increases the yield of dry biomass, reduces the content of 137 Cs in biomass and lysimetric waters. The accumulation of 137 Cs in the biomass of miscanthus when grown on soils contaminated with radionuclides did not exceed the permissible level (DR), and the use of elements of technology helped to reduce the content of 137 Cs by 12–21% compared to control variants. The use of the fertilizer complex «mineral fertilizers + defect + Polymyxobacterin + BioMAG» resulted in the lowest accumulation coefficients of 137Cs, which are 0.07 in the biomass of miscanthus and 0.02 in lysimetric waters, respectively.

ECOLOGICAL AND GEOCHEMICAL ESTIMATION OF THE SPREADING OF TECHNOGENIC ELEMENTS IN THE TERRITORY OF KIVERTSIV NATIONAL NATURAL PARK "TSUMANSKA PUSHCHA"

Analysis of heavy metals content in the soils of the territory showed its heterogeneous distribution and dependence on available sources of technogenic impact. Geochemical accumulation coefficients were calculated and analyzed. The highest concentrations of manganese and chromium are in soils developed on forest deposits. The highest concentrations of nickel and copper are in soils developed on water-glacial deposits. Most of the studied heavy metals exceed the regional geochemical background. In terms of gross content in soils, trace elements form the following geochemical series: Zn> Cu> Pb> Ni> Mn> Cr. Accumulation of lead in forest deposits up to 2-3 MPC was defined. Most heavy metals in the soil are nonuniformity distributed. High values of the variation coefficient (V) – more than 34 % – are typical for inhomogeneous set of data on the concentrations of all investigated heavy metals. The highest index of variation was defined for lead concentration and equal to 170%, the lowest values were obtained for chromium content and equal to 34 % and zinc – 36 %. In the investigated soils there are two types of micronutrient distribution: elements accumulation in organic horizons with concentration decrease in the lower part of the profile and distribution by sedentary – illuvial type. The first type is characterized by increasing distribution of the following elements Zn, Pb; the second one is characterized Co, Ni, Cu, Mn. The ecological and geochemical assessment of technogenic elements distribution of the NNP Tsumanska Pushcha territory is made on the basis of the comparison of technogenic geochemical specialization of different environments (water, soils, etc.). For assessing the role of landscape components in the general geochemical anomaly of the territory, it is proposed to create total ecological and geochemical estimations. It represents the total values of pollutant concentration coefficients in individual components. Further researchers should focus on the analysis of macronutrients and genetic types of soils; determination of the reference content of elements in geochemical landscapes for defining intensity migration and characteristics of elements distribution; conducting biogeochemical zoning.

Study on Texture and Grain Orientation Evolution in Cold-Rolled BCC Steel by Reaction Stress Model

The evolution of texture and grain orientations in a cold-rolled steel of BCC structure was simulated by a reaction stress (RS) model. The results show that cold-rolled texture could be assessed based on a RS model because the stress and strain are considered to remain consistent in the deformation process. The strain consistency is actualized by the cooperation of two plastic strains and an elastic strain. The accumulation range of each reaction stress and different activation abilities of {110}<111> and {112}<111> slip systems strongly affect the calculated deformation textures. The values of reaction stress are influenced by elastic anisotropy; however, the effects are greatly reduced because its corresponding reaction stress accumulation is limited. Typical α-fiber and γ-fiber textures are achieved when the reaction stress accumulation coefficients αijs are chosen suitably. Furthermore, the αij values that are selected based on statistically calculated textures can also be used to simulate the orientation change of multiple orientations. The existence of reaction stress is able to stabilize crystallographically symmetrical orientations under rolling deformation, in which the Schmid factors of several slip systems are identical.

Levels of dose-forming radionuclides in the young perch (Perca fluviatilis) in the Zaporizke Reservoir

It had been investigated the content levels and the coefficients of accumulation from water of the main dose-forming radionuclides (137Cs, 90Sr, 226Ra, 232Th, 40К) in different-age Perca fluviatilis from the Samara Bay and the lower part of the Zaporizke Reservoir. The three age groups of fish were used: one-summer old (0+), two summers old (1+), and three summers old (2+). The obtained data on consecutive reduction of radionuclide activity values in juvenile perch showed that maximal 137Cs content was found in individuals of age (0+), and the minimal one – in individuals aged (1+) from Samara Bay. The maximal accumulation of radioisotopes 90Sr was in individuals aged (0+) in the lower part of the Zaporizke Reservoir, and the minimal one in the perch of age (1+) in the Samara Bay. The highest levels of 226Ra and 40K were found in the (0+) fish from the Samara Bay, and the lowest contents were in individuals aged (2+) in the lower part of the reservoir. The value of the 232Th content level was maximal in the two-summer-olds from the lower part of the reservoir, and the minimal one – in (0+) fish from the Samara Bay. Artificial radionuclide 137Cs was accumulated in the largest amount by perch (0+) from the Samara Bay, and 90Sr – by fish from the lower part of the Zaporizke Reservoir. By values of accumulation coefficients, 232Th was in second place after 137Cs, indicating its significant contribution to the formation of the total dose of radiation. Majority of radioisotopes investigated were more intensively accumulated by the juvenile perch in the Samara Bay compared to the lower part of the Zaporizke Reservoir. The highest level of radionuclide accumulation at both studied sites of the Zaporizke Reservoir has been observed in (0+) fish.

Copper, Manganese and Zinc Bioaccumulation in Some Common Poaceae Species Along Romanian Black Sea Coast

Copper, manganese and zinc bioaccumulation potential was screened for three common Poaceae species, Hordeum murinum ssp. murinum L., Leymus racemosus ssp. sabulosus (M. Bieb.) Tzvelev and Lollium perenne L., abundantly growing along the Romanian Black Sea Coastal area, Constanta County. The concentration of the selected heavy metals was analyzed though atomic absorption spectrometry in samples of aboveground plant organs and soils. To assess the potential for phytoaccumulation, the Biological Accumulation Coefficients (BAC) were calculated. Considering the minimal thresholds widely accepted in literature for Cu, Mn and Zn hyperaccumulators, none of the selected species can fit in this category. The highest average copper concentration was found in Hordeum murinum ssp. murinum L. (5.45 mg/kg). For manganese, the highest value was found in Lollium perenne L. (104.08 mg/kg), while for zinc, the maximum was reached in Leymus racemosus ssp. sabulosus (M. Bieb.) Tzvelev, tissue (62.95 mg/kg). BAC values showed that all species are manganese excluders, with a remarkable maximum value of 0.55 in Lollium perenne. L. All species had average BAC above 1 for Cu and Zn, with a maximum in Leymus racemosus ssp. sabulosus (M. Bieb.) Tzvelev (4.85 and 2.98, respectively). However, there was a significant variation among individuals, usually, a high metal content in plant tissue being associated with low metal concentration in soil. The exception was Lollium perenne L., with BAC constantly above 1 (average BAC of 2.27 for Cu and 1.69 for Zn). These results emphasize a significant potential for phytostabilization of copper- and zinc-rich soils and open the way for heavy metals phytoextraction capacity studies of the Poaceae species along Romanian littoral.

Phytotoxic Effect and Bioaccumulation of Chromium in White Mustard (Sinapis alba L.) Seedlings

The chromium bioaccumulation potential in Sinapis alba L. was studied in experimental hydroponic conditions. Mustard seedlings were grown in nutrient solution containing 50, 100, 250 and 500 ppm Cr. After 10 days, seedlings were analyzed for shoot length, biomass, leaf pigment (chlorophylls and carotenoids) and tissular Cr concentration. The Biological Accumulation Coefficients (BAC) were also determined. Cr content in S. alba dry mass reached 415-2,064 ppm, depending on ambient Cr concentration. BAC ranged between 8.30 to 4.13, with a peak at 100 ppm and lowest values at higher concentrations. Shoot length, biomass and pigment concentration values showed an average decrease at high Cr concentrations (mostly, at 500 ppm), without a definite statistical significance. Results indicate that S. alba is tolerant to high Cr levels and has hyperaccumulative abilities.