Technogenic Radionuclides Research Articles

Geochemical features of the ecosystem of Lake Kolyvan (Altai territory) and related technogenic impact

Regularities of the formation of bottom sediments down to a depth of 1.2 m, as well as factors governing the composition of sediments, waters, and soils in the catchment area of the lake, are discussed. It has been established that the chemical composition of lacustrine sediments is closely associated with the composition of soils in the ambient watersheds, and the soils, in turn, are associated with the composition of the soil-forming rocks. The available data suggest an extremely irregular contamination of the lake system by technogenic radionuclides within the water area. Maximum radiocesium contamination of lacustrine bottom sediments is 350 mCi/km2 (recalculated to year 2000). Concentrations of elements (Cu, Zn, Cr, Ni, Co, Mg, Be, Sb, Mn, and others) in bottom sediments, water, and soils in catchment areas of Lake Kolyvan do not exceed the background values (except for the Hg content in bottom sediments), suggesting that the area under consideration is not contaminated by inorganic technogenic components.

12. Features of137Cs and60Co accumulation in fish of Lake Drūkšiai and its numerical modeling

The study deals with the accumulation peculiarities of the technogenic radionuclides 137Cs and 60Co in different fishes (roach Rutilus rutilus (L.), perch Perca fluviatilis L., and pike Esox lucius L.) of Lake Drūksiai, utilized as a cooler of the Ignalina Nuclear Power Plant. The main regularities in the accumulation of these radionuclides were analyzed, values of 137Cs and 60Co activity concentrations (Bq/kg) in fish of different age were determined in different seasons (spring, summer, and autumn) of the year. 137Cs and 60Co activity concentrations in fish muscles were measured using a gamma spectrometer with a semiconductor HPGe detector. The study of fish contamination with these radionuclides estimated the dependence of radionuclide accumulation on fish age, its trophic level and seasonality. Numerical modeling of freshwater fish contamination with 137Cs and 60Co radionuclides was carried out using the modeling program RESRAD-BIOTA.

The migration of radionuclide’s for the sanitary protection zone of uranium tailings enterprises (LB488)

Mining companies are potential sources of contamination of the environment by various pollutants, including technogenic radionuclides. Stepnogorsk Mining‐Chemical Combine (SMCC) functions over 50 years and is one of the largest complexes for production of uranium oxide and other rare metals. Radioactive waste of SMCC is accumulated in the tailing dumps with an area of 7.82 km2, located in 4 km to the North from Aksu village and Zavodskoy, where concentrated waste is with a mass of 44.17 million tons, and activity of 146.4 thousand Ku. The aim of this work was to evaluate the radiological situation of territories for sanitary protection zone of the tailings dumps (SZZH), including those in close vicinity to workers of the villages Aksu and Zavodskoy.As a result of the pedestrian gamma survey there were identified local, contaminated sites in the North‐East of SZZH SMCC with a length of 5 km. The most contaminated with radionuclides is the top layer of the soil 0‐5 cm. in the North‐East and South‐East direction from SZZH specific activity is 238U, 226Ra in the soil exceed the reference value in 16 times, 210Pb exceeds up to 7 times. In the samples of plants selected from the vicinity of villages in the South‐East and North‐East directions from SZZH it is noted high concentrations of natural radionuclides. In reservoirs of Sulukamys and Manybay thalwegs, located at a distance of 1.5 to 2 km in the Eastern and North‐Eastern part of the tailings dumps, the specific activity of technogenic radionuclides in the tens times higher than control values.On the territory of the village Aksu there were identified local, contaminated sites with a capacity of an equivalent dose of gamma radiation up to 0.86 mSv / h Possible additional radiation dose from external exposure for separate groups of the population of Aksu is from 0,86 mSv to 1,53 mSv per year.

Investigation of radionuclides in the Yenisey River floodplain systems: Relation of the topsoil radionuclide contamination to landscape features

Landscape–radiometric survey and soil sampling performed in the islands of Beriozovy and Balchug (20km downstream the Krasnoyarsk Mining and Chemical Combine), and in the Mikhin Island (180km downstream) showed that the distribution of technogenic radionuclides depends upon the history of contamination and landscape features of the floodplain. Contamination densities of 137Cs appeared to be significantly higher than could be expected from global fallout (1.75–2.5kBq/m2): in 2000 the maximum value for 137Cs in the Beriozovy Island equaled 663kBq/m2, in the Balchug site — 577kBq/m2 and in the Mikhin Island — 518kBq/m2). 137Cs contamination density was practically independent of the remoteness from the KMCC that proved its considerable migration in the water-soluble or fine particulate forms. Vertical distributions of man-made nuclides in soil cores depended upon the different half-life of the studied radionuclides, the soil profile relative altitude, its structure and texture. The two main burial depths of 137Cs activity depended upon the intensity of sedimentation and varied from 5cm to 20–25cm. In 2000 maximum contamination by 60Co and 152,154Eu isotopes was associated with the top layer and decreased exponentially with depth.Obtained data is believed to be important for ecological monitoring of the flood plains subjected to radionuclide contamination.

Technogenic radionuclides in undisturbed Bulgarian soils

This work presents data for the activity concentration of artificial radionuclides in soils from different regions in Bulgaria for the period 1985–2011. The subjects of the study were undisturbed soils from mountainous, hilly, and plain areas. Special attention has been paid to the contamination with the long-lived technogenic radionuclides cesium-137, strontium-90, plutonium-238, and plutonium-239+240. 137Cs was measured by low level gamma spectrometry and 90Sr by radiochemical separation and low level beta counting. The isotopes of plutonium were measured by alpha-spectrometry after a radiochemical procedure of purification and concentration.Cesium-137 and strontium-90 were the main technogenic radionuclides detected in the examined Bulgarian soils few years after the Chernobyl NPP accident. Their content in the soils from high mountain areas is several times higher than that in the soils from the plane areas in the northern part of the country. High heterogeneity in the pollution has been observed. Mean soil activity concentration levels of up to 250Bqkg−1 for 137Cs and 14Bqkg−1 for 90Sr were found in different years. The maximal values registered in separate soil samples were about 1300Bqkg−1 (137Cs) and 24Bqkg−1 (90Sr). The activity concentration levels for 239+240Pu varied between 0.1 and 3.7Bqkg−1. The results indicate that the radioactive pollution of the Bulgarian soils with artificial radionuclides is a result of global fallout and Chernobyl nuclear power plant accident.

Increasing Identification Reliability for Technogenic Low-Activity Radionuclides by Means of the ASKRO Spectrometric Channel

The use of spectrometric information from the ASKRO automated station to increase the reliability of identification of the low-activity technogenic radionuclides 131I, 137Cs, and 140La in the atmospheric boundary layer is examined. The Matros statistical algorithm for processing data with the spectrometer operating in the radiometric mode makes it possible to classify in 45 min the minimum activity 5–10 Bq/m3 with probability ~0.7; false detection comprises ≤0.01 over 100 h. The low identification reliability for lowactivity radionuclides, the relatively long time required for obtaining results, and the impossibility of processing the data obtained during periods of precipitation limit the use of the algorithm. It is shown that spectral processing by the method of the minimum makes it possible to identify in 15–30 min with probability ~1 the minimum activity of 137Cs and 140La – 11 and 6 Bq/m3, respectively – with false detection <10–4.

Influence of freezing on physicochemical forms of natural and technogenic radionuclides in Chernozem soil

AbstractSharp variations of different climatic parameters influence the transport, transfer, and deposition of contaminants in nature. Investigations of the impact of environmental temperature on the fractionation of radionuclides in soil are necessary for adequate assessment of their distribution and bioavailability in case of a nuclear accident. The impact of a sharp decrease of environmental temperature shortly after radioactive contamination on the physicochemical fractionation of natural and technogenic radionuclides in Chernozem soil and its influence on their potential migration ability and bioavailability in case of subsequent warming were evaluated. The soil was contaminated in a laboratory with 241Am, 60Co, 137Cs, 228Ra, 234Th, and U and two temperature regimes were used for storage. Changes of the radionuclides association with various soil phases in the first weeks after contamination were studied. Physicochemical forms of 241Am, 60Co, 228Ra, 234Th, and U were determined using two sequential extraction procedures. The ion-exchangeable forms of 137Cs were evaluated by single extraction with 1 M NH4NO3. The data showed that the freezing, following the radioisotope contamination of the soil, causes an increase of the amount of potentially mobile forms of radiocobalt, radiocesium, radium, and thorium and has an insignificant impact on the fractionation of americium and uranium.

A HISTORICAL OUTLINE OF RADIONUCLIDE CONTAMINATION OF THE YENISEY FLOODPLAIN BASED ON LANDSCAPE AND RADIOMETRIC SURVEY

Distribution of technogenic radionuclides discharged by the Krasnoyarsk Mining and Chemical Combine (KMCC, Zheleznogorsk) in the period from 1958 to 1992 has been studied in floodplain landscapes of the Yenisey river. After shutting down the direct-flow reactors the radioactive contamination of the Yenisey river became dozen times lower. Performed landscape and radiometric studies revealed factors responsible for radionuclide differentiation and the character of radionuclide distribution within two landscape segments of the Yenisey river floodplain. The first segment characterized the impact zone from 16 km to 20 downstream the discharge, the second one was studied in the remote zone as far as 2000 km down the river. Artificial radionuclide contamination was most intensive in the 60-ies of the past century when it reached the Kara Sea. Traces of that contamination were registered in soils of both sites at the depth of 20–50 cm.

Geological and radioecological problems of the objects formed by peaceful nuclear explosions – special radwaste repositories

An assessment of the present status of sites used for peaceful underground nuclear explosions on the territory of the Russian Federation is given. The desirability of recognizing the central zones of nuclear explosions and surface repositories formed near them for storing special radwastes is substantiated. It is shown that formation water is the main substance for removing technogenic radionuclides to the Earth’s surface as well as upper-lying water-bearing levels. Data are presented on the present radio-ecological status of the territories of peaceful nuclear explosions and their possible classification according to the degree of radiation safety.

Comparison of mobility of uranium and technogenic radionuclides in bottom sediments of the Yenisei River

Comparison of mobility of uranium and technogenic radionuclides in bottom sediments of the Yenisei River

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.

EVALUATION OF EXPOSURE OF LAKE DRŪKŠIAI BIOTA REFERENCE ORGANISMS USING PROBABILISTIC METHODS DRŪKŠIŲ EŽERO BIOTOS TESTINIŲ ORGANIZMŲ APŠVITOS VERTINIMAS TAIKANT TIKIMYBINIUS METODUS / ОПРЕДЕЛЕНИЕ МОЩНОСТИ ДОЗЫ ОБЛУЧЕНИЯ РЕФЕРЕНТНЫХ ВИДОВ ОРГАНИЗМОВ ОЗЕРА ДРУКШЯЙ С ИСПОЛЬЗОВАНИЕМ ВЕРОЯТНОСТНЫХ МЕТОДОВ

External, internal and total exposure dose rates received by freshwater biota reference organisms of Ignalina NPP cooling basin Lake Drūkšiai were evaluated by applying ERICA computer code and probabilistic methods. These investigations were based on measurements of radionuclide activity in bottom sediments and water of Lake Drūkšiai (mean values, standard deviations, minimal and maximal values), and ecotoxicologic investigation data published during 1989–2003. The dose rate distributions for every investigated radionuclide and reference organism (average, minimum and maximum dose rate values, 5 and 95 order percentiles) were estimated. In the case of technogenic radionuclides originating from Ignalina NPP, the total dose rate values for Lake Drūkšiai reference organisms do not exceed the maximum permissible dose rate of 10 µGy h−1, which is currently recommended for technogenic radionuclides in the European Union. Due to the ionising radiation of natural radionuclides, the exposure dose rate of reference organisms is much larger if compared with technogenic ones. The largest exposure dose rate caused by 238U amounts to 7.2 µGy h−1 for insect larvae, and 41.8× µGy h−1 — for vascular plants. Santrauka Straipsnyje nagrinėjama Drūkšių ežero hidrobiontų (testinių organizmų) apšvitos dozės galia (µGy h−1), kuriai vertinti taikant tikimybinius metodus, naudota įteisinta Europos Sąjungoje ERICA kompiuterinė programa. Skaičiavimams naudoti radionuklidų aktyvumo koncentracijų Drūkšių ežero dugno nuosėdose ir vandenyje 1989–2003 m. matavimų duomenys (vidutinės reikšmės, standartiniai nuokrypiai, mažiausios ir didžiausios reikšmės). Taikant tikimybinius metodus (Monte Karlo modeliavimą) kiekvienam testiniam organizmui ir radionuklidui įvertintas dozės galios pasiskirstymas, vidutinė, mažiausia ir didžiausia apšvitos vertės bei 5 ir 95 eilių procentilės. Nustatyta, kad technogeninių radionuklidų atveju Drukšių ežero testinių organizmų apšvitos bendrosios dozės galios vertės (95% pasikliautinumo dydis) yra mažesnės užiuo metu technogeniniams radionuklidams Europos Sąjungoje rekomenduojamas didžiausias galimas 10 µGy h−1 dozės galios vertes. Testinių organizmuogon; apšvitos dozės galia dėl gamtinių radionuklidų poveikio yra kur kas didesnė nei dėl technogeninių. Pažymėtina, kad gamtinių radionuklidų atveju didžiausia apšvitos dozės galia yra nulemta 238U, pavyzdžiui, vabzdžių lervoms apšvita siekia 7,20×100 µGy h−1, induotiesiems vandens augalams −4,18×10+1 µGy h−1. Резюме С помощъю компьютерной программы ERICA и использованием вероятностных методов исследована мощность дозы облучения гидробионтов в озере Друкшяй. Для расчетов использованы измерения концентрации активности радионуклидов в воде и донных отложениях озера Друкшяй (среднее значение и стандартное отклонение; минимальные и максимальные значения) путём анализа литературных данных за 1989–2003 гг. С использованиемвероятностных методов (метод Monte Carlo) подсчитаны распределения мощности дозы от каждого заданногорадионуклида со средним, минимальным и максимальным значениями, рассчитаны 5й и 95й перцентили.Установлено, что в случае техногенных радионуклидов суммарная мощность дозы облучения гидробионтов (запределами 95го перцентиля) не превышает максимальной нормы облучения в 10 µGy h−1, которая рекомендованаЕвропейским Союзом как максимально возможная в случае техногенных радионуклидов. Мощность дозы облучения референтных видов организмов от природных радионуклидов значительно выше, чем от техногенных.Максимальная мощность дозы облучения в случае природных радионуклидов вызвана 238U, например, 7,20×10µGy h−1 для личинок насекомых, 4,18×10+1 µGy h−1 для водных сосудистых растений

The pebble fines contribution into radiation environment of the river Yenisei floodplain in an influence zone of the Krasnoyarsk mining and chemical combine (KMCC)

The results of investigation of radioactive contamination of the river Yenisei bed pebbles in an influence zone of the KMCC (especially in its near-field part) are presented in this work. It is demonstrated, that pebbles can contain up to 30 % of the total amount of γ-emitting technogenic radionuclides (TRN) in the places with overlying soils. In addition, river bed pebbles, situated in permanently washing riverside sections of islands and banks, can contain significant amount of TRN too. These facts considerably increase an estimation of TRN reserves in the Yenisei floodplain. Without the contribution of the river bed pebbles the fraction of TRN, accumulated in the underlying and tow path pebbles in the near and far-field influence zones of the KMCC, can reach 7,9% for 137 Cs, 5,8% for 152 Eu, 5,6% for 154 Eu and 60 Co of their total amount.

Peculiarities of distribution of anthropogenic radionuclides in soils and soil fractions of conjugated floodplain landscapes of the Yenisey River

The Yenisey River belongs to one of the main Siberian water systems flowing into the Arctic basin. Technogenic radionuclides have entered this system due to activities at the Krasnoyarsk Mining and Chemical Combine (KMCC), situated approximately 40km downstream from the city of Krasnoyarsk (Zheleznogorsk), which began operations in August of 1958 (start-up of thefirst straight-through reactor, a second reactor was operated from 1961). In the period of 1958 to 1992 the river channel and flood plain were exposed to contamination at great distances downstream from the waste discharge point. Various long-lived radionuclides were measured in the environment such as 137 Cs, 60 Co, 152 Eu, 154 Eu with half-lives of 30.2, 5.3, 13.3 and 8.6 years correspondingly. Both reactors were decommissioned in 1992 and since then radionuclide discharges to the river have decreased by several tens of times. The first information about the considerable radionuclide contamination of the Yenisey River for a reach extending to approximately 2000km downstream of Krasnoyarsk and detected up to the entry of the river into the Arctic basin was obtained in the early 1970-ies [1] but these data were not available for the wider scientific community. Detailed radioecological studies of the Yenisey contamination started in the 1990-ies. The purpose of this study, performed within two international projects STREAM and ESTABLISH, was to investigate patterns of and environmental factors affecting the distribution of anthropogenic radionuclides in flood plain landscapes of the Yenisey River at different distances from the discharge point of the Krasnoyarsk Mining and Chemical Combine down to the estuarine zone. The study area included islands in the mid reaches of the Yenisey River and locations within the estuary. A variable pattern of distribution and local accumulation of long-lived radionuclides in floodplain landscapes was observed that appeared to be strongly dependent upon landscape- and hydrological factors.

Metrological support for the ASKRO spectrometric channel

The metrological support for monitoring of ground layer of the atmosphere with ASKRO gamma spectrometers requires determining their sensitivity in the measurement geometry of technogenic radionuclides. The application of numerical modeling, the method of similarity of radiation fields, and a combined method in evaluating sensitivity of a spectrometer is examined. It is shown that the model method overstates the sensitivity and does not permit checking the spectrometer. To decrease the error of estimation a combination of measurements of the efficiency of the spectrometer for a point source and a Monte Carlo calculation of the incident flux is used. An estimate of the total relative error of determination of the sensitivity is given and it is shown that it can be verified. The estimates obtained for the sensitivity increase the minimum measured volume activity of the spectrometer at energies less than 1 MeV.

Detection of technogenic radionuclides at low concentrations when monitoring nuclear power plant emissions using an arms spectrometric channel

The application of statistical algorithms in the problem of early detection of technogenic, nuclear power plant emissions in the atmosphere near the ground by means of the spectrometric channel of ARMS (Automatic Radiation Monitoring System) is examined. It is noted that the changes in the radon progeny content which are associated with the diurnal behavior of the intensity of turbulent mixing influence the variance of the readings in the 131I and 137Cs detection ranges. As a result, when a stationary Poisson model is used in the algorithm the number of false alarms increases and the algorithm becomes ineffective. Regional corrections lowering the probability of false alarms to ≤10–3 with correct detection probability ≥0.7 were introduced into the detection and classification algorithm on the basis of the results of monitoring performed over the course of a year for intervals with stationary γ background.

The role of vegetation in the regulation of fluxes of technogenic radionuclides at different stages after radioactive fallout

In the remote period after the radioactive fallout in the Chernobyl accident, the biological cycle of 137Cs in pine forests of the northern forest-steppe zone and in those of Bryanskoe Polesye become essentially different. In the cleaner northern zone with dark-gray forest soil, the 137Cs flux to the soil with litterfall exceeds its influx to the vegetation by a factor of 5; i.e., the 137Cs cycle differs from that of stable K, the descending flux being still dominant. In the more contaminated Bryanskoe Polesye zone with podzolic illuvial-iron sandy soil, the annual 137Cs influx to above-ground vegetation via root uptake exceeds its return to the soil with litterfall, i.e., the 137Cs cycle approaches the biological cycle of stable K.

Сорбционная очистка радиоактивно загрязненных вод фильтрующими материалами на основе гранулированного глауконита

The paper deals with developed by the authors sorption method of water bodies treatment against technogenic radio nuclides with the use of natural non-organic sorbents. A technological scheme of granulated glauconite production has been proposed, sorption and operational properties of the sorbent has been determined, results of the water treatment filter tests with granulated glauconite loading have been presented.

Radioactive contamination as a type of soil degradation

Radioactive contamination of soils is considered as a separate type of degradation decreasing their fertility. Natural soil radioactivity is described. The main sources of technogenic radionuclides for the soil cover (global radionuclide fallout after nuclear weapons tests, the operation of nuclear facilities, radioactive waste) were shown. The phytomelioration of soils containing radionuclides was assessed. Issues were analyzed related to the remediation of agricultural soils after radiation accidents associated with the release of radionuclides into the environment: the discharge of radionuclides into the Techa River (1949–1953) and the Kyshtym (Southern Urals, 1957), Windscale (United Kingdom, 1957), and Chernobyl (Ukraine, 1986) accidents. The hazard of radioactive contamination of the soil-plant cover was assessed from two viewpoints: the anthropocentric (sanitary-hygienic) principle, when the degree of radioactive contamination of agricultural crops and the conformity of their radionuclide content to radiological standards are taken into account (maximum permissible concentrations of radionuclides), on the one hand, and the ecocentric (biospheric, environmental) approach, when the consequences of the irradiation of soil biota and living terrestrial organisms caused by radionuclides present in the soils are taken into account (conformity to the radiation standards and permissible radiation doses), on the other hand. For some technogenic radionuclides, the use of these principles for assessing the hazard of radioactive contamination of the soil was exemplified, which is of importance for determining the rehabilitation strategy of agricultural lands contaminated with radionuclides.

Cross-correlations and time dependences of radionucllides content in silts of the mountain reivers in Zakarpattya region: 2006-2008 years

Investigation of content and change dynamics of natural (U-, Th-chains, K-40) and technogenic radionuclides in the slits of the Uzh, Latorytsya, Borzhava river has been carried out. Cross-correlation dependences and influence of seasonal and spatial factors have been established. The mechanism of “self-purification” of Carpathian mountains from anthropogenic activity and possibility of investigated GAN use as tracers of geochemical features have been discussed.