Peculiarities of Phytoplankton Development in the Zaporizhzhya Reservoir under Conditions of Anthropogenic Load

The radionuclides, which have occurred in the aquatic ecosystem are quickly redistributed there. Most of them come through the water phase to the benthal deposit, while the other part of them accumulates in suspensions and hydrobionts. Even low concentrations of radionuclides in water contributes to its radioactive contamination that poses risks to the environment. The radionuclide contamination of freshwater ecosystems is particularly pressing issue, since water with low mineralization enhances the radionuclides activity in the sediments compared to the water by a factor of 10 or even more, and in the animals by hundreds and thousands of times. Phytoplankton is the fundamental autotrophic link of aquatic ecosystems. Due to a large total sorption surface, it is able to absorb, retain and transmit radionuclides along the food chains, leading to a deterioration of the environmental position of the reservoir. Phytoplankton was sampled in the summer of 2019 at 5 sites along the course of the Zaporizke reservoir, which differ in hydrological and hydrochemical conditions: Samara Bay, Festivalnyi pier, Monastyrsky island, creek of the Mokra Sura river and the lower section of the reservoir (near Viyskove village). The specific radioactivity of phytoplankton samples was determined using generally accepted radiochemical methods and gamma spectrometry. The specific radioactivity of radionuclides is given in bequerels per kilogram (Bq/kg) of fresh, natural weight. Statistical processing of research results was carried out using generally accepted methods of variation statistics for a small sample using the Excel 2010 software package. Purpose of the work. To determine the content of natural ( 232 Th, 226 Ra and 40 K) and artificial ( 137 Cs and 90 Sr) radionuclides in phytoplankton at different sites of the Zaporizke reservoir. The content of artificial radionuclides in the phytoplankton of the Zaporizke reservoir averaged as follows: 137 Cs – 7.61±0.501 Bq/kg; 90 Sr – 1.13±0.242 Bq/kg. The maximum values of the content of artificial radionuclides in phytoplankton were recorded in the area of the Festivalnyi pier and the minimum values were recorded near Viyskove village ( 137 Cs) and Samara bay ( 90 Sr). In total, phytoplankton has a relatively low content of artificial radionuclides, which is explained by its low content in water. Hydrobionts receive the main portion of radiation exposure from natural sources of radiation. About 300 natural radionuclides have been identified in the environment; among them 226 Ra, 232 Th and 40 K make a significant contribution to the total natural radioactivity. The specific activity of natural radionuclides in the water area of the Zaporizke reservoir on average was following: 226 Ra – 95.45±7,010 Bq/kg; 232 Th – 85.66±4,013 Bq/kg; 40 K – 185.26±23.74 Bq/kg. The lowest content of natural radionuclides was observed in the phytoplankton of the Samara bay. The maximum recorded specific activity of 226 Ra and 40 K was observed in the creek of the Mokra Sura river, which may indicate an increased content of radionuclides in the water of this river, because the river is polluted throughout its length by industrial, agricultural and municipal wastewater. It has been found that the specific activity of natural radionuclides 226 Ra, 232 Th and 40 K was 80-320 times higher than that of the artificial ones ( 90 Sr and 137 Cs). The distribution of radionuclides in the elements of the freshwater ecosystem is characterized by accumulation coefficients. According to the accumulation coefficients with respect to water, the sequence of accumulation of radionuclides in the phytoplankton of the Zaporizke reservoir has been arranged in descending order: 137 Cs> 232 Th> 226 Ra> 40 K> 90 Sr. The accumulation coefficients of 40 K and 90 Sr are 11-22 times less than those of 137 Cs and 232 Th, which is quite appropriately, because freshwater algae are more able to accumulate 137 Cs. For most of the radionuclides studied, the maximum values of accumulation coefficients have been recorded in phytoplankton in the area of the Festivalnyi pier ( 137 Cs, 90 Sr, 232 Th) and the creek of the Mokra Sura river ( 226 Ra, 40 K). The latter is associated with both the hydrochemical and hydrological conditions of these sites, and with increased anthropogenic impact, especially in the area of the river creek. The data obtained indicate that there is a potential threat of accumulation of radionuclides in phytoplankton and their transfer further along food chains. With reference to the above mentioned, it is important to monitor the content of radionuclides in phytoplankton in order to minimize their transmission through the food chain and preserve the biodiversity of aquatic ecosystems.

Goal. Research of the effective specific radioactivity of phosphorite of the group of deposits of the Kharkiv region (Izyum district) in order to determine the possibility of using them for smelting ferrophosphorus in accordance with the radiation safety standards of Ukraine (NRBU-97). Method. The study of the effective specific activity of natural phosphorite radionuclides was carried out using the Spectrum Master 92X device (GEM-3085 detector). Processing of the spectrum, identification of peaks, determination of the relative error of the corrected peak planes in the sample spectrum and the background spectrum, as well as the calculation of the specific activity were performed in automatic mode with further analysis of the report on intermediate calculations. The results. It was determined that the calculated effective specific activity of natural phosphorite radionuclides according to the NRBU-97 method is 440 Bq/kg, which corresponds to the II class of the action level for similar types of raw materials. At the same time, it is shown that when smelting ferrophosphorus in order to increase the acidity of the phosphorite solution (ratio % SiO2 / % CaO), it is advisable to add silica to the charge, which reduces the concentration of radioactive elements to the normalized level. Scientific novelty. For the first time, the effective specific activity of natural radionuclides in phosphorite of the Malokomyshevakh deposit (Kharkiv region, Izyum district) was determined. Practical significance. According to the results of the work, it is possible to establish the expediency of using domestic phosphorites for the electrosmelting of ferrophosphorus in the production of alloys based on ferrous and non-ferrous metals. Key words: phosphorites, effective specific activity of natural radionuclides, mineral ores, electromelting, ferrophosphorus.

The aim of the work is to study the distribution of radiation parameters in the profile of alluvial gray humus (turf) typical soils of the floodplain of the Irtysh and Tobol rivers in the vicinity of settlements: flux density Rn-222, specific activity of natural radionuclides – Ra-226, Th-232, K-40, their effective specific activity. Measurements of the 222Rn flux density were performed by the KAMERA-01 radon monitoring system, and the specific activity of natural radionuclides using the SKS-99 Sputnik gamma-ray spectrometer. The ranges of specific activity of natural radionuclides in the soil profile of Ra-226 are 3-26 Bq/kg; Th-232 – 3-28 Bq/kg; K-40 – 175-404 Bq/kg. The nature of the distribution of the specific activities of natural radionuclides 226Ra and 232Th in the soil profile of alluvial gray humus (turf) typical soils depends on their content in the soil-forming rocks and is not influenced by the physico-chemical properties of the soil – moisture, actual acidity and density of addition. The profile distribution of the specific activity of 40K revealed statistically significant correlations with the actual soil acidity. The average value of the effective specific activity of natural radionuclides (61 Bq/kg) in the soil does not exceed the safe level for the population living in the studied territories and environmental components – 100 Bq/kg. The pH from the soil surface is less than the level set in OSPORB-99/2010 – 80 mBq/(m2·s). Alluvial gray humus (turf) typical soils in the floodplain of the Irtysh and Tobol rivers in the vicinity of the settlements of Yarkovsky (Sorokino village), Vagaysky (Injura village, Vagai village) and Tobolsk (Russian Medyanki village, Ermakovo village, Ovsyannikovo village) districts of the Tyumen region represent a low risk exposure for humans. The results obtained are important as regional data in assessing the radiation safety status of the population living in the study area.

The purpose of the study was to establish the patterns of spatial distribution of radioactivity of technogenic 137Cs and natural radionuclides 232Th, 226Ra, 40K in urban soils of Monchegorsk. Location and time of the study. Soil samples, were collected in summer 2018 in the Monchegorsk city, Murmansk region, Russia. To study the specific activity of radiocesium and natural radionuclides, soil samples were taken from topsoil (0-5 cm) at 82 sites, including 68 sites within the city territory (urban soils) and 14 sites beyond the city limits in the subtorch areas strongly affected by the Severonickel factory. Similar studies of urban soils in Monchegorsk had not been carried out previously. Methods. During expeditionary work and laboratory research, soil, radiological, and mathematical and statistical methods were used. When carrying out gamma spectrometric measurements, radionuclides 137Cs, 226Ra, 232Th and 40K were determined on a low-background semiconductor gamma spectrometer ORTEC (USA) based on a high-purity coaxial germanium detector GEM10P4–70 (HPGe) with a SBS-75 pulse signal processor and Gamma-software. The resolution of the gamma spectrometer along the 1.33 MeV line (60Co) was 1.75 keV, and the relative efficiency was 15%. Calibration and quality control of gamma spectrometric measurements was carried out using volumetric activity measurements with 1-L Marinelli vessels of different densities (RITVERZ, Russia-Germany). Main results. The values of specific activity of radionuclides in soil samples were as following: in the technogenic 137Cs up to 31.3 Bq/kg and in the subtorch soils up to 63.4 Bq/kg. Specific activity of natural radionuclides in urban soils reached to 14.2 Bq/kg for 226Ra, whereas in the subtorch soils it reached 21.6 Bq/kg. The specific activity of 232Th in urban soils reached 18.3 Bq/kg, with 17 Bq/kg registered for the subtorch soils. As for 40K, its specific activity reached 498 Bq/kg in the urban soils and 317 Bq/kg. Conclusion. The gamma survey of the Monchegorsk territory did not reveal any anomaly in radiation. The dose rate of gamma radiation in the city does not exceed 0.074 μSv/hour, which is less than the values elsewhere in Russia, ranging from 0.04 to 0.20 μSv/hour. The obtained data about specific activity of technogenic 137Cs and natural radionuclides 232Th, 226Ra, 40K in the Monchegorsk soils are typical for the Murmansk region.

Introduction. Children’s playgrounds are an integral part of the infrastructure of urban and rural settlements, a place of active recreation and development of children. Analysis of the regulatory framework governing the location and environmental condition of the territory of children’s playgrounds, the order of their operation allowed establishing the absence of a single document that permits to control their content. Material and methods. Sanitary-and-epidemiologic condition of playgrounds were assessed according to their location relative to residential development and roads, the extent of landscaping, the levels of pollution of atmospheric air and soil, the level of gamma radiation, the effective specific activity of natural radionuclides in the sand of the sandbox. Microbiological contamination of soil and sand of sandboxes was estimated by the content of pathogenic microorganisms and worm eggs in them. A total of 82 sites were surveyed: 38 in the historical part of the city and 44 in the areas of the modern development of St. Petersburg. Statistical analysis of the research results was carried out using the program Statistica 8. Results. The emissions of vehicles polluted the air of playgrounds with nitrogen dioxide It was found to be by 3 times higher than the maximum permissible concentrations (MPC) in the Central part of the city and 2 times - in the areas of modern development. The concentrations of lead in the soil exceeded MPC by 5-10 times in the historical part of the city and by 1.1 - 3 MPC in the modern districts, the complex index of soil pollution with Zc accounted for 64-128 and 16-32, respectively. According to sanitary and bacteriological indices, the studied soil samples were classified as “clean”. The specific effective activity of natural radionuclides in samples of sand sandboxes ranged from 46 ± 12 - 320 ± 35 Bq/kg There was common a violation of the integrity of the sites and acts of vandalism. Conclusion. The results of the study convincingly prove the need to create a single regulatory document defining the structure responsible for the choice of the territory for children’s playground, its maintenance, operation of equipment, as well as the rules of control and supervision.

The paper deals with the study of the radiation state of the soil and herbaceous vegetation represented by perennial grasses (Poa pratensis, Calamagrostis epigejos, Rubus saxatilis, Carex acuta, Phleum pratense) in the south of the Tyumen Region. The content and distribution of natural radionuclides in soil and herbaceous vegetation was studied in the Nizhnetavdinsky District of the Tyumen Region at the site of an underground nuclear explosion. Sampling and laboratory tests were carried out according to generally accepted methods. Soil samples were taken at the epicenter of the explosion and at the cardinal directions. Layer-by-layer sampling allowed us to study the vertical distribution of radionuclides in the soil profile. Sampling of perennial grasses was carried out at the same sampling points. Radiation studies of soil and vegetation samples were carried out on the Progress-2000 spectrometric complex. The authors have revealed specific activity of natural radionuclides (K-40, Th-232 and Ra-226) in the profile of grey forest soil in the Nizhnetavdinsky District. They have calculated effective specific activity of radionuclides in the soil. The comparative analysis of the obtained results with the data on administrative areas in the south of the Tyumen Region showed that in the soil of the Nizhnetavdinsky District specific activity of natural radionuclides is higher than in the South region in general. The specific activity of natural radionuclides in perennial grasses of the Nizhnetavdinsky District was determined, and the coefficient of accumulation of radionuclides was calculated.

Specific activities of natural (40K, 226Ra and 232Th) radionuclides in 250 beach sand samples collected from 5 beaches in 5 districts which are Rachadapisek beach in Nong Chick district, Talokapo beach in Yaring district, Panarae beach in Panarae district, Wasukri beach in Saiburi district and Pamai beach in Mai Kaen district in Pattani province, have been studied and measured. Experimental results were obtained by using a high-purity germanium (HPGe) detector and gamma spectrometry analysis system and also evaluated by using the standard reference materials IAEA-SOIL-6 which were obtained from Office of Atoms for Peace. Experimental set-up and measurement were operated and carried out at laboratory research building, Office of Atoms for Peace, Bangkok. It was found that, the mean values of specific activities of 40K in Rachadapisek, Talokapo, Panarae, Wasukri and Pamai beaches were 427.58 ± 14.09, 1090.62 ± 54.28, 463.95 ± 14.06, 449.07 ± 13.80 and 433.49 ± 12.77 Bq/kg, respectively. The mean values of specific activities of 226Ra were 31.10 ± 7.63, 160.68 ± 8.07, 84.41 ± 13.09, 33.98 ± 7.76 and 44.42 ± 10.17 Bq/kg, respectively. The mean values of specific activities of 232Th were 11.40 ± 1.75, 356.65 ± 6.59, 74.50 ± 3.07, 16.04 ± 1.78 and 26.86 ± 2.08 Bq/kg, respectively. Furthermore, the results of the specific activities of natural radionuclides (40K, 226Ra and 232Th) in this areas were also used to evaluate the gamma absorbed dose rates (D), the radium equivalent activity (Raeq), the external hazard index (Hex) and the annual external effective dose rate in this area. Furthermore, experimental results were also compared to research data in the southern region of Thailand, the Office of Atoms for Peace (OAP) annual report and the recommended values which were proposed by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR, 1988, 1993, 2000).The first section in your paper

Natural radionuclides and 137Cs distributions and their relationship with sedimentological processes in Patras Harbour, Greece

The influence of heat treatment (burning) of building materials on the effective specific activity of natural radionuclides was investigated. Analysis and processing of the obtained results allowed to obtain a consistent pattern of this process for each material. It has been established that the effective specific activity of natural radionuclides decreases along with growth of temperature of building rocks treatment. The results showed that it is possible to reduce the effective specific activity of natural radionuclides managing technological production modes and, consequently, to reduce the radiation doses of the population from these materials.

The analysis of the radiation survey results of freshwater ecosystems of three rivers and the Cheremshansky Bay of the Kuibyshev Reservoir in the vicinity of State Scientific Centre “Research Institute of Atomic Reactors” (SSC RIAR, Institute) before the start of the MBIR fast neutron reactor operation was carried out. The content of natural (K-40, Ra-226, Th-232) and artificial (Sr-90, Cs-137) radionuclides in the main components of freshwater ecosystems: surface and underground waters, bottom sediments, floodplain soils and vegetation, and ichthyofauna was estimated. It has been shown that the specific activity of Cs-137 in the waste water of industrial storm sewerage (PLK-1) of the enterprise is 10-70, Sr-90 2-10 times higher compared to the surface waters of reservoirs of its zone of influence. This is due to the removal of radionuclides from the site of local contamination in the sanitary protection zone of SSC RIAR. In Cheremshansky Bay, downstream, the concentration of radioisotopes decreases by 8-50 times due to dilution processes and their sorption by bottom sediments and hydrobionts. It is noted that the sorption properties of bottom sediments are determined by the presence of organic compounds in their composition. The multidirectional nature of the accumulation of artificial radionuclides in floodplain soils and plants is shown. In some cases, it is determined by the distance from the source of gas-aerosol emissions of radioisotopes and affects the secondary pollution of freshwater ecosystems. Monitoring data demonstrate a stable decrease in the content of artificial radionuclides in surface waters. In Cheremshansky Bay in 2005-2020 for Cs-137 it was 5 times, for Sr-90 it was 3 times. It has been noted that in recent years, the specific activity of artificial radionuclides in sewage of SSC RIAR, surface and underground waters, as well as fish in the zone of enterprise influence is at the level of the regional background and is 1-3 orders of magnitude lower than the current radiological standards. The importance of further radioecological monitoring of freshwater ecosystems in the SSC RIAR location area after the commissioning of the MBIR for assessing the impact of the new reactor on humans and the environment is shown.

This study aims to measure heavy metals (HMs) concentration and radioactivity concentration levels in fertilizer and pesticide samples collected from local markets in Sana’a, Yemen. Gamma spectroscopy employing a Survey Sodium Iodide NaI (TI) RIIDEYM-G detector was used for radiation and dose assessments. As for heavy metal analyses, this study used Inductively Coupled Optical Emission Spectroscopy (ICP-OES). Thirty samples were collected from local markets in Sana’a, Yemen. Radioactivity measurements show low levels of radioactivity concentration. The average dose rates due to fertilizer and pesticide samples were 1.14 and 1.07 mSv/y, respectively. These values are nearly equal to the recommended annual radiation dose rate limit (1mSv/y) recommended by the International Commission on Radiological Protection (ICRP). For heavy metal analysis, it was found that the average concentrations of heavy metals (HMs) (cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), nickel (Ni), lead (Pb), and zinc (Zn)) in the fertilizer samples were 1.08 mg/kg, 4.944 mg/kg, 13.8495 mg/kg, 274.371 mg/kg, 3.30446 mg/kg, 15.35686 mg/kg, and 24.4547 mg/kg, respectively. Heavy metal concentrations in fertilizer samples were mainly less than European (EU) guideline limits, with the exception of a few samples. The average concentrations of heavy metals (Cd, Cr, Cu, Fe, Ni, Pb, and Zn) in the pesticide samples were 0.8 mg/kg, 0.5784 mg/kg, 52.280 mg/kg, 73.4651 mg/kg, 2.4482 mg/kg, 3.199 mg/kg, and 1.1309 mg/kg, respectively. The heavy metal concentrations in pesticide samples were less than the corresponding values in fertilizer samples.

The article is focused on the results of studying the radiation condition of the soil and grassy vegetation represented by perennial grasses (meadow bluegrass, reed warbler, stonecrop, clover, sedge, timothy) in the South of the Tyumen region. The specific activity of natural radionuclides (K-40, Th-232 and Ra-226) in the profile of gray forest soil of the Nizhnetavdinsky district was established, the specific effective activity of radionuclides in the soil was calculated. Comparative analysis of the obtained results together with the data on administrative districts of the South of the Tyumen region showed that in the soil of the Nizhnetavdinsky district, specific activity of natural radionuclides exceeds the similar indicator typical for the South of the region.

The Onega District is among the first ten municipalities of the Arkhangelsk Region with the highest incidence of neoplasms warranting radiological studies. The aim of this research was to study content and distribution of natural and technogenic radionuclides in the urban soils of the Onega municipality and to identify the main low-intensity radioactive anomalies as well as to provide an objective assessment of radiation risks to health of the local population. Methods: A total of 99 soil samples were taken in several parts of the town. Specific activity of radionuclides was assessed using a gamma spectrometer. Standard soil-morphological, soil-geochemical, radiometric, mathematical-statistical and cartographic methods were applied. Results. Color contrast of the soils in different areas indicates the preservation of their relationship with the parent soil. The values of the effective specific activity of natural radionuclides in soil samples ranged from 28 to 99 Bq/kg. Low-intensity radioactive anomalies were revealed for the first time in town. It was determined that the composition of the town's soils ensures that the effective specific activity of natural radionuclides is not exceeded for materials of classes I and II used in construction. Conclusions. The revealed low-intensity radioactive anomalies can be associated with the influx of radionuclides into the soil as a part of coal combustion products in the local heating stations taking into account the active use of coal combustion products by the local population. It is necessary to assess the long-term effect of low-intensity radioactive anomalies on the population. Further research should concentrate on associations between the epidemiological patterns of diseases and radioactivity in Onega.

In the present paper, an investigation on the natural and anthropic radioactivity and heavy metals content in a basalt aggregate for concrete from Sicily, Southern Italy, was performed as a case study. In particular, the evaluation of the specific activity of radium-226, thorium-232, potassium-40 and caesium-137 radionuclides was performed by using High-Purity Germanium (HPGe) γ-ray spectrometry, together with the estimation of several indexes developed to evaluate the radiological risk for the population related to radiation exposure, i.e., the alpha index (Iα), the radium equivalent activity (Raeq), the absorbed γ-dose rate (D) and the annual effective dose equivalent outdoor (AEDEout) and indoor (AEDEin). Moreover, measurements of the average heavy metals (arsenic, cadmium, copper, mercury, nickel, lead, antimony, thallium and zinc) concentrations in the analyzed sample were performed by using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Furthermore, with the aim to investigate any possible chemical pollution, the Enrichment Factor (EF), Geo-accumulation Index (Igeo), Contamination Factor (CF) and Pollution Load Index (PLI) were assessed. Finally, the identification of the source of the aforementioned radioisotopes of natural origin was carried out by X-ray diffraction (XRD), thus identifying the major mineralogical phases present in the investigated basalt aggregate for concrete.

It has been shown that heavy metals toxicity to humans is as a result of long term or high level exposure to pollutants common in the environment including the air, water, food and numerous consumer products such as the cosmetics and toiletries. In this study, we assessed the levels of toxic metals in different cosmetic products sold at local shops in Baghdad. The cosmetic items included Eye Shadow. These items were purchased from various shops at different locations in Baghdad. The cosmetics were analyzed for heavy metals (Copper, cadmium, lead, and nickel) after digestion with concentrated acids HNO3: HCl in ratio 1:3. The concentrations of the selected toxic heavy metals were determined in duplicate using aflame atomic absorption spectrophotometer. The samples analyzed contained a detectable amount of the metals of interest. The concentration of the heavy metals in the samples ranged from 0.092 to 25.57 ppm. It is obvious from the present study that the use of some cosmetic products exposes users to low concentrations of toxic heavy metals which could constitute potential health risk to users since it has been known that heavy metals can accumulate in the biological system over time and are known to induce skin problems or diseases such as cancer. Further research to better understand the sources of heavy metals in cosmetic product is recommended.