Review on uranium in soil: levels, migration

The problems of radioactive contamination of biosphere with the 238U in recent years have attracted a large number of experts in various fields of knowledge. Natural radionuclides are an integral part of the biosphere. They are concentrated everywhere: in rocks, in soil, water, air and food. Various types of phosphorus fertilizers and other natural ameliorants used in agriculture are also an additional source of heavy natural radionuclides. The review describes the behaviour and migration of 238U in biosphere, which depend on various factors acting simultaneously. It is noted that the behaviour of 238U in the soil depends on the forms of its presence in it and the physical and chemical properties of the soil. The processes of sorption and desorption of 238U by different soil types are significant indicators

КРИТЕРИИ РЕАБИЛИТАЦИИ ОБЪЕКТОВ И ТЕРРИТОРИЙ, ЗАГРЯЗНЕННЫХ РАДИОНУКЛИДАМИ В РЕЗУЛЬТАТЕ ПРОШЛОЙ ДЕЯТЕЛЬНОСТИ: ЧАСТЬ 1. ВЫБОР ПОКАЗАТЕЛЕЙ ДЛЯ ОБОСНОВАНИЯ КРИТЕРИЕВ РЕАБИЛИТАЦИИ

The article examines issues of rehabilitation of facilities and territories contaminated by the man-made and natural radionuclides as a result of past activities of enterprises of nuclear and non-nuclear industries. Rehabilitated facilities and territories contaminated with radionuclides as a result of past activities of enterprises must meet criteria based on the analysis of requirements of existing normative legislative documents in the field of radiation protection of the population taking into account the recommendations of international organizations that are justified dose quantities and derivative indicators used in criteria setting. It is shown that the criteria for rehabilitation of facilities and territories contaminated by man-made radionuclides as a result of past activities, should be the same regardless of whether the contamination occurred as a result of planned activities of the enterprise or due to unauthorized activities. For these situations, the criteria for rehabilitation should be based on dose quantities and derived indicators of the residual contamination of the environment after rehabilitation. Only indicators of radiation safety of the environment can be used in almost all cases for justification of the criteria for rehabilitation of facilities and territories contaminated by natural radionuclides. The article shows that such approaches are applicable not only to environmental media contaminated as result of past activities of enterprises of traditional non-nuclear industries but the mining of uranium and thorium ores. From the standpoint of modern classification of industrial waste with a high concentration of natural radionuclides, the characteristics of these wastes according to their potential radiation hazard to people and the environment are identical.В статье рассматриваются вопросы реабилитации объектов и территорий, загрязненных техногенными и природными радионуклидами в результате прошлой деятельности предприятий ядерной и неядерных отраслей промышленности. На основе анализа требований действующих нормативных правовых документов в области радиационной безопасности населения с учетом рекомендаций международных организаций обоснованы дозовые величины и производные показатели, используемые при установлении критериев, которым должны соответствовать реабилитированные объекты и территории, загрязненные радионуклидами в результате прошлой деятельности предприятий. Показано, что критерии реабилитации объектов и территорий, загрязненных техногенными радионуклидами в результате прошлой деятельности, должны быть одинаковыми независимо от того, произошло загрязнение в результате плановой деятельности предприятия или несанкционированной деятельности. Для этих ситуаций критерии реабилитации должны быть основаны на дозовых величинах и производных показателях, характеризующих остаточное загрязнение среды обитания после окончания реабилитационных мероприятий. При загрязнении объектов и территорий природными радионуклидами практически во всех случаях для обоснования критериев их реабилитации могут быть использованы только показатели радиационной безопасности объектов среды обитания. В статье показано, что такие подходы применимы не только к объектам среды обитания, загрязнение которых произошло в результате прошлой деятельности предприятий традиционных неядерных отраслей промышленности, но и предприятий по добыче урановых и ториевых руд. С позиций современной классификации производственных отходов с повышенным содержанием природных радионуклидов характеристики этих отходов по их потенциальной радиационной опасности для населения и окружающей среды идентичны

РАЗРАБОТКА НАЦИОНАЛЬНОГО СТАНДАРТА «БЕЗОПАСНОСТЬ ЖИЗНЕДЕЯТЕЛЬНОСТИ НАСЕЛЕНИЯ НА РАДИОАКТИВНО ЗАГРЯЗНЕННЫХ ТЕРРИТОРИЯХ. БЕЗОПАСНОЕ ИСПОЛЬЗОВАНИЕ ЛЕСОВ НА ЗЕМЛЯХ ЛЕСНОГО ФОНДА И ИНЫХ КАТЕГОРИЙ. ОСНОВНЫЕ ПОЛОЖЕНИЯ»

As a part of the implementation of the Federal target program «Managing the consequences of radiation accidents for the period till 2015» the National Standard «Safe life of the population on contaminated territories. Safe use of forests of forestry fund lands and other wooded lands. The basic framework». Its aim is to ensure safe use of forests on forestry fund and other wooded lands in the areas affected by radiation incidents and accidents, including radiation protection providing of the population presence in the forested sites and consumption of forest products.В рамках реализации Федеральной целевой программы «Преодоление последствий радиационных аварий на период до 2015 года» разработан национальный стандарт «Безопасность жизнедеятельности населения на радиоактивно загрязненных территориях. Безопасное использование лесов на землях лесного фонда и иных категорий. Основные положения». Стандарт направлен на обеспечение безопасного использования лесов на землях лесного фонда и землях иных категорий, находящихся в составе радиоактивно загрязненных территорий в результате радиационных аварий и катастроф, включая обеспечение радиационной безопасности пребывания населения на лесных участках и использования гражданами лесной продукции

Behavior and Impact of Zirconium in the Soil–Plant System: Plant Uptake and Phytotoxicity

Because of the large number of sites they pollute, toxic metals that contaminate terrestrial ecosystems are increasingly of environmental and sanitary concern (Uzu et al. 2010, 2011; Shahid et al. 2011a, b, 2012a). Among such metals is zirconium (Zr), which has the atomic number 40 and is a transition metal that resembles titanium in physical and chemical properties (Zaccone et al. 2008). Zr is widely used in many chemical industry processes and in nuclear reactors (Sandoval et al. 2011; Kamal et al. 2011), owing to its useful properties like hardness, corrosion-resistance and permeable to neutrons (Mushtaq 2012). Hence, the recent increased use of Zr by industry, and the occurrence of the Chernobyl and Fukashima catastrophe have enhanced environmental levels in soil and waters (Yirchenko and Agapkina 1993; Mosulishvili et al. 1994 ; Kruglov et al. 1996)

Modelling of

A set of countermeasures aimed at reducing 137Cs uptake by plant products includes agrochemical measures based on changes in the soil properties after the application of ameliorants. The dynamic models for studying the effect of the application of potassium fertilizers and dolomite powder on 137Cs accumulation in plants are presented. Conceptual approaches to the development of models are based on the identification of mechanisms governing a complex of physico-chemical processes in soil after the use of ameliorants. The developed models were parameterized for soils of the coniferous forest located in the Bryansk region in area suffered from the radioactive fallout after the Chernobyl accident. Effects of ameliorants and time of their application on 137Cs behaviour in the soil-plant system are assessed. The contribution of soil chemical and biological processes to the decrease in the radionuclide uptake by plants is estimated

Comparative analysis of

A quantitative analysis of 137Cs bioavailability in forest soils in the long term after the Chernobyl NPP accident based on a 3 years (1996-1998) investigation is presented. Five sites with different trees composition and properties of soil were studied to identify factors determining radiocaesium transfer to trees and different under story species. The following parameters were investigated: 137Cs activity concentrations and its speciation in various horizons of forest soil, accumulation of this radionuclide by different species of under story vegetation and distribution of their root biomass in the soil profile. It has been shown that one decade after the deposition maximum 137Cs activity in soil of the experimental sites considered is located in different soil layers dependent on moisture regime, characteristics of litter and soil properties. High level of heterogeneity of 137Cs specific activity in different parts of tree, which is related to physiological peculiarities of their functions, has been shown. The data obtained have demonstrated a non-uniform character for 137Cs distribution along trunks, which can be explained by radionuclide fixation by walls of xylem vessels and by changes in geometry along the tree trunk. It has been found that the radial distribution of 137Cs in the tree trunk is dependent on the availability of 137Cs in soil, which governs the transfer of this radionuclide via xylem sap, and on the properties of the xylem. The accumulation of 137Cs by both trees and under story species was influenced by 137Cs vertical distribution and availability in soil as well as by the root (mycelia) biomass distribution in different soil horizons. A "bioavailability factor", which takes into account the above factors, is proposed for comparative analyses of 137Cs transfer from soil to plants in different types of forest ecosystems

The classification of Russian soils on the basis of transfer factors of radionuclides from soil to farm crops

The accumulation of radionuclides in crops varies considerably for different soil-climatic zones being largely dependent on the soil properties. To group the data, relationships between TFs to different crops and soil properties were analysed. As a criterion for classification of mineral soils by transfer factors the granulometric composition (texture) was chosen. The generalisation of data within the identified soil groups has demonstrated that for different crop/soil combinations the volume of sampling is not the same. Therefore, a statistical processing of data was carried out. Clear-cut relationships between 90Sr and 137Cs accumulation in different crops and identified soil groups were found. The obtained data allowed us to derive rather stable ratios of geometric means for transfer factors for different soil groups which confirm the validity of data generalisation within the identified soil groups