Radioactive Contamination Of Soil Research Articles

Prompt Mapping of Radioactively Contaminated Areas

The paper presents a methodology for prompt mapping of radioactively contaminated areas. The efficiency of obtaining cartographic information is achieved by using correlation dependences between the characteristics of radioactive contamination obtained during various radiological surveys of contaminated areas. The method of spatial interpolation based on regression-kriging is used to formalize the data on radioactive contamination. This method allows combining the information resulting from direct measurements of density of territory contamination by radionuclides we are interested in with the information contained in other characteristics of radioactive contamination received at the surveyed area (for example, ER). Such an approach allows more accurate mapping of 137Cs deposition density and concentration of its activity in the root layer of soil, as well as significant reduction of the time and cost to survey the mapped area (sampling, sample preparation and measurement of samples). This, in turn, accelerates and reduces the cost for mapping of radioactively contaminated territories (fields, lands, sites). The methodology has been tested on the fields contaminated by radionuclides resulting from the Chornobyl accident in the Narodychi, Polissia and Ivanivka Districts and has proved its performance and efficiency. Comparison and analysis of the obtained maps of radioactive contamination of the territory show that in the conditions of limited amount of data on direct measurements and time limit, the use of correlation dependences between the characteristics of radioactive contamination of soil is often the only possible way to increase the information content and accuracy of the obtained cartographic information.

Радио экологические проблемы в лесах России

Обобщены итоги исследований отдела радиационной экологии и экотоксикологии леса с момента его создания, обозначены проблемы, приведены достижения и направления дальнейшего развития лесной радиационной экологии в научном и практическом направлениях. The article summarizes the research results of the Department of Forest Radiation Ecology and Ecotoxicology of VNIILM since its inception. A brief description of the occurrence of the radioactive contamination problem of Russian forests is given. Lists the main radiation accidents. It is noted that most of the radiation accidents and incidents are rural in nature and lead to pollution of natural landscapes, including forests. Radiationrelated information is required for rehabilitation activities in polluted forests.The source of such information is radiation monitoring of forests (RMF). At present, in the late stage of radiation accidents, RMF faces new challenges in monitoring the results of chronic exposure of forest ecosystems. The article describes the problem of forest fires in areas of radioactive contamination.It is shown that all forest fires in areas with a density of radioactive soil contamination with cesium137 37kBq/m2 (1 Ci/km2) or more can be classified as radioactive forest fires. Reforestation and afforestation in radioactively contaminated areas is considered an important part of countermeasures. They allow you to manage the natural processes of restoration of forest vegetation, directing them to solving the problems of rehabilitation of contaminated areas. The article discusses a number of problems associated with chronic irradiation of forest ecosystems. Their insufficient knowledge is noted. The possibility of multidirectional effects of ionizing radiation on components of forest biota and significant modification of their biological stability is indicated.The results of studies of the reactions of various types of forest flora and fauna to existence under the conditions of exposure to chronic and acute irradiations confirm this conclusion.The obtained results allow us to identify a new direction of forest radioecology, which studies the effect of radioactive contamination and ionizing radiation on the sanitary condition of forest ecosystems and the development of pathogenic foci radiation forest pathology. The article emphasizes the need for indepth comprehensive research involving specialists from various fields of knowledge.

Logistical Simulation Modeling for Planning a Soil Remediation Process

This paper describes the development of a discrete event simulation model using the FlexSim software to support planning for soil remediation at Korean nuclear power plants that are undergoing decommissioning. Soil remediation may be required if site characterization shows that there has been radioactive contamination of soil from plant operations or the decommissioning process. The simulation model was developed using a dry soil separation and soil washing process. Preliminary soil data from the Kori 1 nuclear power plant was used in the model. It was shown that a batch process such as soil washing can be effectively modeled as a discrete event process. Efficient allocation of resources and efficient waste management including volume and classification reduction can be achieved by use of the model for planning the soil remediation process. Cost will be an important criterion in the choice of suitable technologies for soil remediation but is not included in this conceptual model.

Accumula- tion radionuclides 137Cs in plants of grass-bush in tier subors of Ukrainian Polissia

The modern radioactive contamination of the representatives of the grass-bush tier of pine plantations in the conditions of subors forests of Ukrainian Polissia is investigated. The density of radioactive soil contamination within the sample plots varied from 148 to 440 kBq/m2. Significant fluctuations of the specific activity values of 137Cs for all research species were found — from 6166 Bq/kg to 171862 Bq/kg. The maximum values of 137Cs were found in terrestrial phytomass of Pteridium aquilinum (L.) Kuhn, and minimal — in Vaccinium uliginosum L. Intensity indices of 137Cs in terrestrial phytomass of grass-bush tier for all research species varied in wide ranges: the coefficient of accumulation from 0.8 to 58.6, the transition factor — from 17 to 574 m2·kg–1·10–3. According to the results of one-factor dispersion analysis, the representatives of the grass-bush cover on the ability to accumulate 137Cs were classified in 6 groups. By the accumulation intensity of 137Cs in subors forests, the plants can be placed in the following order: Pteridium aquilinum (L.) Kuhn > Melampyrum pretense L. > Calluna vulgaris (L.) Hull > Vaccinium myrtillus L. > Molinia caerulea (L.) Moench > Vaccinium vitis-idaea L. > Ledum palustre L. > Vaccinium uliginosum L. The concentration of 137Cs in the species of grass-bush cover has a close linear relationship with the magnitude of the density of soil radioactive contamination.

Measurement of uranium distribution coefficient and 235U/238U ratio in soils affected by Fukushima dai-ichi nuclear power plant accident

Fukushima Daiichi Nuclear Power Plant (FDNPP) accident resulted radioactive contamination in soil due to deposition of mainly radiocesium as well as many long-lived radionuclides surrounding a large area around FDNPP. Depending upon environmental conditions, radionuclides in soil can be mobilized in aquatic systems. Therefore, the fate and transfer of these radionuclides in the soil water system is very important for radiation protection and dose assessment. In the present study, soil and water samples were collected from contaminated areas around FDNPP. Inductively coupled plasma mass spectrometry (ICP-MS) is used for total uranium concentration. Emphasis has been given on isotope ratio measurement of 235U/238U ratio using thermal ionization mass spectrometry (TIMS) that gives us the idea about its contamination during accident. For the migration behavior, its distribution coefficient (Kd) has been determined using laboratory batch method. Chemical characterization of soil with respect to different parameters has been carried out. The effect of these soil parameters on distribution coefficient of uranium has been studied in order to explain the radionuclide mobility in this particular area. The distribution coefficient values for uranium are found to vary from 30 to 36000 L/kg. A large variation in the distribution coefficient values shows the retention or mobility of uranium is highly dependent on soil characteristics in the particular area. This variation is explained with respect to soil pH, Fe, Mn, CaCO3 and organic content. There is a very good correlation of uranium Kd obtained with Fe content. There is no enrichment of 235U has been noticed in the studied area.

ЛИКВИДАЦИЯ ЯДЕРНОГО НАСЛЕДИЯ: РАДИАЦИОННО-ГИГИЕНИЧЕСКИЕ КРИТЕРИИ БЕЗОПАСНОСТИ ДЕЗАКТИВИРОВАННЫХ УЧАСТКОВ ТЕРРИТОРИИ, ЗДАНИЙ И СООРУЖЕНИЙ

The article presents approaches to the establishment of criteria (requirements) of radiation safety to the decontaminated areas of the territory, buildings and decommissioned facilities of use of atomic energy and other types of practical activities with sources of ionizing radiation. The main directions of further use of the decontaminated areas of the territory, buildings, and constructions, including 5 scenarios of restricted and unrestricted use, are determined; the criteria of radiation safety in the term of a dose constraint of a critical group of the population in 0.3 mSv/year living or working on decontaminated objects are established; the controlled parameters of the radiation situation and their levels, as well as the list of radionuclides subject to control are justified. The article presents the values of specific activity (Bq/kg) of residual radioactive contamination of soils and materials of buildings and structures, the radiation dose to the population in which will not exceed 0.3 mSv/year. Based on the presented data, draft sanitary rules and guidelines have been developed.

Effect of radioactive contamination of the medium on the durability of steel 20

The effect that the ionizing radiation caused by radioactive contamination of soil exerts on the surface of carbon steel 20 samples, on their corrosion resistance, and on operation reliability according to lowcycle fatigue tests (taking into account that fatigue is one of the main causes of failures resulting from corrosion and mechanical damage of thin-wall metal structures, in particular, of pipelines) was studied. It was shown that even low activity levels (below maximum permissible levels) caused corrosion loss of the metal and a decrease in the operation reliability. Synergistic protective compounds suppressing the destructive radiation effects and ensuring reliable operation of metal structures due to chelation of the surface metal atoms were developed using computer simulation.

Radioactive contamination of the soils of Georgia

Abstract After 29–30 years from Chernobyl atomic plant accident the main soil types of Georgia have been examined on contamination presence of 137Cs and 90Sr. Level of radioactive contamination of soils (137Cs deposition) we can separate three levels: I - 0–10 kBq/m2 - Black, Cinnamonic, Raw carbonate, Mountain meadow, Chernozems, Black forest brown, Primitive and Yellow soils; II - 10–37 kBq/m2 - Red, Bog and Yellow forest brown soils; III - > 37 kBq/m2 - Yellow podzolic soils. In a big majority of soils 137Cs deposition of layer 0–20 cm does not exceed 37 kBq/m2 (1 Ci/km2), that allows us to attribute this examined sample points to non-contaminated territories. In five points of sampling with maximum 137Cs deposition in a layer of 0–20 cm have been measured specific activities of 137Cs in a layer of 20–40 cm and have been evaluated 137Cs deposition in a layer of 0–40 cm. Results for most of the soils also does not exceed 37 kBq/m2 (1 Ci/km2). Exclusion is Yellow podzolic soil near to v.Jvari (West Georgia), where 137Cs deposition was 38.0 and 70.4 kBq/m2 accordingly in layers of 0–20 cm and 0–40 cm. We can attribute this zone to radiological contamination, particularly to living zone of privileged socio-economic status. In Yellow podzolic soils we can observe high mobility of 137Cs primary in kaolinite composition of clay fraction and in connection to this lowering of intensity of non-exchangeable absorption by soil of this radionuclide. In all soils 90Sr deposition in a layer of 0–20 cm does not exceed 11.1 kBq/m2 (0.3 Ci/km2) that allows us to attribute examined territories to “relatively satisfying situation”.

Шляхи підвищення продуктивності люпину вузьколистого в умовах радіоактивного забруднення районів зони Полісся

Шляхи підвищення продуктивності люпину вузьколистого в умовах радіоактивного забруднення районів зони Полісся

Концентрація 137cs і важких металів у м’ясі качок, вирощених у різних зонах радіоактивного забруднення

The purpose. To study features of growing ducks on aboriginal feedstuffs at different systems of their growing and to develop methods of production of ecologically safe duck meat in terrains with different density of radioactive contamination of soils. Methods. 2 groups of young animals of ducks are generated: I group (control) – non-exercise growing in poultry yards with easy approach to water in pans; II group (test) – exercise growing on the natural bounded pools. Determination of specific activity of 137Cs in feedstuffs, water and killing products of an auk was carried out with the use of AMA-05E and BDEG-20R, the concentration of heavy metals was measured using atomic absorption method on spectrophotometer S-115M. Results. In conditions of extensive growing experimental ducks in II and III zones of radioactive contamination on aboriginal feedstuffs and unbalanced rations on calcium, phosphorus and microelements they got meat of ducks with concentration of 137Cs did not exceed allowances (DU-2006=200 Becquerel/kg) and fluctuated within the limits of 9,3 — 75,9 Becquerel/kg. Concentration of lead and cadmium in muscles and liver of experimental ducks did not exceed maximum concentration limit. Conclusions. Ecological safety of production of duck meat as one of main products of feed of population in regions with radioactive contamination was proved theoretically and in practice.

THE AVERAGE ANNUAL EFFECTIVE DOSES FOR THE POPULATION OF THE SETTLEMENTS OF THE RUSSIAN FEDERATION ATTRIBUTED TO ZONES OF RADIOACTIVE CONTAMINATION DUE TO THE CHERNOBYL ACCIDENT (FOR THE ZONATION PURPOSES), 2017

The Chernobyl accident in 1986 is one of the most large-scale radiation accidents in the world. It led to radioactive contamination of large areas in the European part of the Russian Federation and at the neighboring countries. Now, there are more than 4000 settlements with the total population of 1.5 million in the radioactively contaminated areas of the Russian Federation. The Bryansk region is the most intensely contaminated region. For example, the Krasnogorskiy district still has settlements with the level of soil contamination by cesium-137 exceeding 40 Ci/km 2 . The regions of Tula, Kaluga and Orel are also significantly affected. In addition to these four regions, there are ten more regions with the radioactively contaminated settlements. After the Chernobyl accident, the affected areas were divided into zones of radioactive contamination. The attribution of the settlements to a particular zone is determined by the level of soil contamination with 137 Cs and by a value of the average annual effective dose that could be formed in the absence of: 1) active measures for radiation protection, and 2) self-limitation in consumption of the local food products. The main regulatory document on this issue is the Federal law № 1244-1 (dated May, 15 1991) “On the social protection of the citizens who have been exposed to radiation as a result of the accident at the Chernobyl nuclear power plant”. The law extends to the territories, where, since 1991: 1) the average annual effective dose for the population exceeds 1 mSv (the value of effective dose that could be formed in the absence of active radiation protection measures and self-limitation in consumption of the local food products); 2) soil surface contamination with cesium-137 exceeds 1 Ci/km 2 . The paper presents results of calculations of the average effective doses in 2017. The purpose was to use the dose values (SGED 90 ) in zonation of contaminated territories. Therefore, the calculations have been done under the assumption that the doses were formed in the absence of active radiation protection measures and self-limitation in consumption of the local food products. The dose to population, rather than the density of radioactive contamination of soil by 137 Cs, is the most objective characteristic of the actual radiation exposure to the residents of the contaminated areas.

Mechanisms for surface contamination of soils and bottom sediments in the Shagan River zone within former Semipalatinsk Nuclear Test Site

The Shagan River is the only surface watercourse within the former Semipalatinsk Test Site (STS). Research in the valley of the Shagan River was carried out to study the possible migration of artificial radionuclides with surface waters over considerable distances, with the possibility these radionuclides may have entered the Irtysh River. The investigations revealed that radioactive contamination of soil was primarily caused by the first underground nuclear test with soil outburst conducted at the “Balapan” site in Borehole 1004. The surface nuclear tests carried out at the “Experimental Field” site and global fallout made insignificant contributions to contamination. The most polluted is the area in the immediate vicinity of the “Atomic” Lake crater. Contamination at the site is spatial. The total area of contamination is limited to 10–12 km from the crater piles. The ratio of plutonium isotopes was useful to determine the source of soil contamination. There was virtual absence of artificial radionuclide migration with surface waters, and possible cross-border transfer of radionuclides with the waters of Shagan and Irtysh rivers was not confirmed.

Radiocesium fallout in the grasslands on Sakhalin, Kunashir and Shikotan Islands due to Fukushima accident: the radioactive contamination of soil and plants in 2011

The accident at the Fukushima Dai-ichi Nuclear Power Plant has resulted in radioactive contamination of environmental media and food in the Far East of Russia, particularly in the Sakhalin Region. To obtain the knowledge about the 134Cs and 137Cs spatial distribution in the Sakhalin Region, soil samples were collected at 31 representative grassland sites on Sakhalin, Kunashir and Shikotan islands (43.80°–46.40° N and 142.73°–146.84° E) in the middle of May and around the end of September to early October 2011. In the autumn, vegetation samples (mixed grass/forb crop and bamboo, Sasa sp.) were collected together with soil samples. Maximum measured activity concentrations (on dry weight) of 134Cs and 137Cs in soil were 30 Bq kg−1 and 210 Bq kg−1, respectively. Within soil profile, 134Cs activity concentrations declined rapidly with depth. Although for both sampling occasions (in the spring and autumn) the radionuclide was completely retained in the upper 3–4 cm of soil, a deeper penetration of the contaminant into the ground was observed in the autumn. In contrast with 134Cs, activity concentrations of 137Cs demonstrated a broad range of the vertical distribution in soil; at most sites, the radionuclide was found down to a depth of 20 cm. This resulted from interfering the aged pre-accidental 137Cs and the new Fukushima-borne 137Cs. To calculate contribution of these sources to the inventory of 137Cs, the 134Cs:137Cs activity ratio of 1:1 in Fukushima fallout (the reference date 15 March 2011) was used. The maximum deposition density of Fukushima-derived 137Cs was found on Shikotan and Kunashir Islands with average density of 0.124 ± 0.018 kBq m−2 and 0.086 ± 0.026 kBq m−2, respectively. Sakhalin Island was less contaminated by Fukushima-derived 137Cs of 0.021 ± 0.018 kBq m−2. For the south of Sakhalin Island, the reference inventory of pre-Fukushima 137Cs was calculated as 1.93 ± 0.25 kBq m−2 (reference date 15 March 2011). For Shikotan and Kunashir Islands, the pre-Fukushima reference levels of 137Cs ground contamination appeared to be higher: on average, 2.81 ± 0.35 kBq m−2. Maximum measured activity concentrations (on wet weight) of 134Cs and 137Cs in the vegetation were 5 Bq kg−1 and 18 Bq kg−1, respectively. Soil-to-plant aggregated transfer factors, Tags, for 134Cs were more than an order of magnitude higher than those for 137Cs. For the above-ground biomass density of 1 kg per m2 (wet weight), plant contamination may contribute approximately 2% and 0.1% to the ground deposition of Fukushima-derived and pre-accidental 137Cs, respectively.

An early survey of the radioactive contamination of soil due to the Fukushima Dai-ichi Nuclear Power Plant accident, with emphasis on plutonium analysis

A field survey was carried out soon after the Fukushima Dai-ichi Nuclear Power Plant accident. Gamma-ray emitting radionuclides and plutonium isotopes in a series of soil samples collected from the heavily contaminated areas outside the 20-km exclusion zone, as well as from Okuma Town adjacent to the plant, were measured. Volatile radionuclides such as 131I, 134Cs, and 137Cs contributed largely to the released radioactivity. Higher depositions of these nuclides were observed in areas to the northwestern—including Okuma Town and Iitate Village, which is at a distance of 25-45 km from the plant. The results obtained were consistent with the levels and distributions estimated later by the Japan-USA joint-survey (Asahi Shimbun Company, 2011). Trace amounts of plutonium isotopes originating from the accident were detected mainly in soil samples from Iitate Village and in limited soil samples from Okuma Town. The detected levels of 239,240Pu contamination due to the accident were considered to be less than a millionth those of the 137Cs contamination.

Estimation of radioactive contamination of soils from the “Balapan” and the “Experimental field” technical areas of the Semipalatinsk nuclear test site

In spite of the long history of the research, radioactive contamination of the Semipalatinsk nuclear test site (SNTS) in the Republic of Kazakhstan has not been adequately characterized. Our cartographic investigation has demonstrated highly variable radioactive contamination of the SNTS. The Cs-137, Sr-90, Eu-152, Eu-154, Co-60, and Am-241 activity concentrations in soil samples from the “Balapan” site were 42.6–17646, 96–18250, 1.05–11222, 0.6–4865, 0.23–4893, and 1.2–1037 Bq kg−1, correspondingly. Cs-137 and Sr-90 activity concentrations in soil samples from the “Experimental field” site were varied from 87 up to 400 and from 94 up to 1000 Bq kg−1, respectively. Activity concentrations of Co-60, Eu-152, and Eu-154 were lower than the minimum detectable activity of the method used. Concentrations of naturally occurring radionuclides (K-40, Ra-226, U-238, and Th-232) in the majority of soil samples from the “Balapan” and the “Experimental field” sites did not exceed typical for surrounding of the SNTS areas levels. Estimation of risks associated with radioactive contamination based on the IAEA clearance levels for a number of key radionuclides in solid materials shows that soils sampled from the "Balapan" and the “Experimental field” sites might be considered as radioactive wastes. Decrease in specific activity of soil from the sites studied up to safety levels due to Co-60, Cs-137, Sr-90, Eu-152, Eu-154 radioactive decay and Am-241 accumulation-decay will occur not earlier than 100 years. In contrast, soils from the “Experimental field” and the “Balapan” sites (except 0.5–2.5 km distance from the “Chagan” explosion point) cannot be regarded as the radioactive wastes according safety norms valid in Russia and Kazakhstan.

Effects of low-level radioactive soil contamination and sterilization on the degradation of radiolabeled wheat straw

After the explosion of reactor 4 in the nuclear power plant near Chernobyl, huge agricultural areas became contaminated with radionuclides. In this study, we want to elucidate whether 137Cs and 90Sr affect microorganisms and their community structure and functions in agricultural soil. For this purpose, the mineralization of radiolabeled wheat straw was examined in lab-scale microcosms. Native soils and autoclaved and reinoculated soils were incubated for 70 days at 20 °C. After incubation, the microbial community structure was compared via 16S and 18S rDNA denaturing gradient gel electrophoresis (DGGE). The radioactive contamination with 137Cs and 90Sr was found to have little effect on community structure and no effect on the straw mineralization. The autoclaving and reinoculation of soil had a strong influence on the mineralization and the community structure. Additionally we analyzed the effect of soil treatment on mineralization and community composition. It can be concluded that other environmental factors (such as changing content of dissolved organic carbon) are much stronger regulating factors in the mineralization of wheat straw and that low-level radiation only plays a minor role.

Multifractal structure of the 137Cs fallout at small spatial scales

Regardless of the surface area of the site, the spatial distribution of radioactive contamination of soils with 137Cs for Chernobyl fallout is described by a lognormal distribution. Moreover, the spatial pattern of the radioactive contamination of soil is random geometrical multifractal field. Due to that, any contamination spot, when studied in detail, decomposes into a multitude of small spots decomposing further into a multitude of smaller spots etc. Similar patterns are apparently characteristic for fallout of other radionuclides, the Fukushima fallout, as well as atmospheric fallout of non-radioactive dust and aerosols.

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.

Eco-economic approach to evaluation of agricultural lands polluted by chemicals and radionuclides

A comparative analysis of the existing methods of land evaluation has shown that none of them ensures a comprehensive assessment of the diverse economic and ecological functions of soils. An original methodology developed by the authors includes the evaluation of the soil ecological quality in addition to the traditional cost assessment of land plots, and adequate correction coefficients accounting for the chemical and radioactive contamination of soils are suggested. The effect of changes in the market price of the land on the inflation processes is analyzed.

On-site radioactive soil contamination at the Andreeva Bay shore technical base, Northwest Russia

The radioactive waste (RAW) storage site at Andreeva Bay in the Russian Northwest has experienced radioactive contamination both as a result of activities carried out at the site and due to incidents that have occurred there in the past such as accidental releases of radioactive materials. The site is an interesting case study for decommissioning due to the extremely large amounts of radioactivity present at the site and the conditions under which it is stored; very little has been previously published in the scientific literature about this site. This paper complements the paper describing dose rates at Andreeva Bay which is published in this issue of Journal of Environmental Radioactivity by the same authors. This study presents new data related to the activity concentrations of 137Cs and 90Sr in surface soils and measurements of α- and β-particle fluxes taken at different areas around the site. Limited data on 60Co is also presented. The results of the study indicate that the main areas of site contamination are associated with the former spent nuclear fuel storage facility at Building 5, due to accidental discharges which began in 1982. Substantial contamination is also observed at the solid radioactive waste storage facilities, probably due to the ingress of water into these facilities. More than 240 samples were measured: maximum contamination levels were 1 × 10 6 Bq/kg 137Cs (mean value 4.1 × 10 5 Bq/kg) and 4 × 10 6 Bq/kg 90Sr (mean value 1.2 × 10 5 Bq/kg). Localised patches of α and β contamination were also observed throughout the site.