High Levels Of Radionuclides Research Articles

Study on the relationship between the dispersal of wild boar (Sus scrofa) and the associated variability of Cesium-137 concentrations in its muscle Post-Fukushima Daiichi Nuclear Power Plant accident

After the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in 2011, the wild boar (Sus scrofa) population within the Fukushima Evacuation Zone (FEZ) increased substantially in size and distribution. This growing population and their potential dispersal from the FEZ, where they are exposed to high levels of radionuclides, into the surrounding landscape underscores the need to better understand boar movement patterns in order to establish policies for managing shipping restrictions for boar meat and develop management strategies. In this study, we quantified the genetic population structure of boar in and around Fukushima prefecture using sequence data of the mitochondrial DNA control region and MIG-seq analysis using 348 boar samples to clarify boar dispersal patterns. Among boar samples, seven Asian haplotypes and one European haplotype were detected. The European haplotype originated from hybridization between domestic pigs and native boar in the evacuation zone after the accident and was detected in 15 samples across a broad geographic area. Our MIG-seq analysis revealed genetic structure of boar was significantly different between boar inhabiting the eastern (including FEZ. i.e., East clade) and western (i.e., West clade) regions in Fukushima prefecture. In addition, we investigated the relationships between boar dispersal and Cesium (Cs)-137 activity concentrations in boar muscle using MIG-seq genetic data in Nihonmatsu city, located in the central-northern region of Fukushima. High Cs-137 activity concentrations, exceeding 1000 Bq/kg, in boar muscle had a significantly high probability of belonging to the East clade within localized regions. Thus, our results provide evidence of the spatial scale of dispersal of individuals or offspring of boar from the FEZ. Results of this research also indicate that dispersal of individuals between areas with different Cs-137 contamination levels is one of the biggest factors contributing to variation in Cs-137 activity concentration in boar muscle within localized regions.

Distribution of radioelements in rock-water-air systems from the Caldas Novas hydrothermal complex (GO), Brazil

Radioactivity measurements have been done in rocks and groundwater samples of Caldas Novas Hydrothermal Complex, Goiás State, Central Brazil, aiming to investigate if the rock matrices could be responsible for transferring high levels of radionuclides into the atmosphere and liquid phase. Gamma spectrometry showed that rocks presented low concentrations of uranium (eU = 226Ra), thorium (eTh = 228Th) and 40K as confirmed by laboratorial radon (222Rn) emanation experiments that yielded low values in both, liquid and gas phases. The monitored dissolved radionuclides in waters were 222Rn, 210Pb, 223Ra, 224Ra, 226Ra, 228Ra, 234U, and 238U, whose activity concentration was compared with the guideline reference values established by the World Health Organization (WHO) for drinking water. The results obtained for the committed effective dose (CED), based on a drinking water ingestion rate of 2 L/day throughout a year, did not surpass the WHO reference level of 100 μSv/year.

Uranium isotopes in groundwater in Ho Chi Minh City and related issues: Health risks, environmental effects, and mitigation methods

Groundwater is regularly used for many purposes, such as drinking and agricultural irrigation systems. Still, it contains high levels of radionuclides (e.g., 238U, 232Th, and 226Ra) that are potentially hazardous to humans and the environment. In this study, activity concentrations of uranium isotopes were analyzed in 15 groundwater samples taken from 15 bored wells in Thu Duc district, Ho Chi Minh City, Vietnam. Environmental effects of the irrigation system with groundwater on agricultural soil in the study area were assessed by models. It was found that the activity concentrations of 238U and 234U in groundwater samples were in the ranges of (13.5–268.7) mBq l−1 and (20.2–438.3) mBq l−1, respectively. The ratio 234U/238U values were ranged from 1.12 to 2, with an average value of 1.44. Based on the model prediction, 25 years irrigation with the groundwater can inject 94.8 Bq both uranium isotopes in 1 kg topsoil. For investigated groundwater samples, the proposed removal method using K2FeO4 removed 74.28% and 81.04% for 234U and 238U, respectively.

RADIOACTIVE DISEQUILIBRIUM AND DYNAMIC OF NATURAL RADIONUCLIDES IN SOILS IN THE STATE OF PERNAMBUCO-BRAZIL.

Environmental radioactivity studies have been allowed establishing radiometric patterns in several area of the earth's crust. The work was conducted through radiometric analyses of regions with high levels of radionuclides and others with no history of anomalies. The research allowed establishing the radiometric profile of soils in the state of Pernambuco, Brazil, using a gamma spectrometry system. The specific activities ranged from 16.5 to 287.5 Bq kg-1 for 238U, 2.0 to 191.7 Bq kg-1 for 226Ra, 1.3 to 281.4 Bq kg-1 for 232Th and from 5.0 to 2600.9 Bq kg-1 for 40K. The results showed areas with low levels of ionizing radiation. However, for 40K some points presented high values, although non-representative of the number of samples investigated. The 226Ra/238U and 232Th/238U ratios allowed to determine the radioactive imbalance condition and to obtain information about aspects of soil availability providing an assessment of the dynamics of these radionuclides.

Thyroid Abnormalities Associated with Protracted Childhood Exposure to131I from Atmospheric Emissions from the Mayak Weapons Facility in Russia

Between 1948 and 1960, the Mayak nuclear weapons facility in Ozyorsk, Russia discharged relatively high levels of radionuclides, primarily (131)I, into the atmosphere, resulting in appreciable exposure to the residents of Ozyorsk. To evaluate the association between thyroid diseases and childhood exposure to radioiodines, we screened 894 Ozyorsk residents born between 1952 and 1953. The study population was comprised of 581 exposed individuals living in Ozyorsk during the years of heaviest exposure and 313 nonexposed individuals who moved to Ozyorsk when radiation exposure from Mayak largely had ended. The screening protocol included a patient interview, palpation of the thyroid, cervical lymph nodes and salivary glands, an ultrasound examination, and measurement of fT4, TSH and TPOAb. Twenty-eight percent of the study group was diagnosed with a thyroid abnormality. The prevalence of nodular disease was significantly higher in the exposed group (20.7%) compared with the nonexposed (14.4%) group (relative risk = 1.4, 95% CI = 1.1; 1.9). Risks were larger for solitary nodules and for nodules > or = 10 mm in diameter. Expansion of the study to increase the number of persons screened as well as detailed dose estimation would offer an unique opportunity to evaluate thyroid disease in relation to chronic exposure to radioiodines during childhood.

Radiation effects in wild terrestrial vertebrates – the EPIC collection

The paper presents data on radiation effects in populations of wild vertebrate animals inhabiting contaminated terrestrial ecosystems. The data were extracted from the database “Radiation effects on biota”, compiled within the framework of the EC Project EPIC (2000–2003). The data collection, based on publications in Russian, demonstrates radiation effects in the areas characterized with high levels of radionuclides (Kyshtym radioactive trace; “spots” of enhanced natural radioactivity in the Komi region of Russia; territories contaminated from the Chernobyl fallout). The data covers a wide range of exposures from acute accidental irradiation to lifetime exposures at relatively low dose rates. Radiation effects include mortality, changes in reproduction, decrease of health, ecological effects, cytogenetic effects, adaptation to radiation, and others. Peculiarities of radiation effects caused by different radionuclides are described, also the severity of effects as they appear in different organisms (e.g. mice, frogs, birds, etc.).

Rapid sediment accumulation and microbial mineralization in forests of the mangrove Kandelia candel in the Jiulongjiang Estuary, China

Rates of sediment accumulation and microbial mineralization were examined at three Kandelia candel forests spanning the intertidal zone along the south coastline of the heavily urbanized Jiulongljiang Estuary, Fujian Province, China. Mass sediment accumulation rates were rapid (range: 10–62 kg m −2 y −1) but decreased from the low- to the high-intertidal zone. High levels of radionuclides suggest that these sediments originate from erosion of agricultural soils within the catchment. Mineralization of sediment carbon and nitrogen was correspondingly rapid, with total rate of mineralization ranging from 135 to 191 mol C m −2 y −1 and 9 to 11 mol N m −2 y −1; rates were faster in summer than in autumn/winter. Rates of mineralization efficiency (70–93% for C; 69–92% for N) increased, as burial efficiency (7–30% for C; 8–31% for N) decreased, from the low-to the high-intertidal mangroves. Sulphate reduction was the dominant metabolic pathway to a depth of 1 m, with rates (19–281 mmol S m −2 d −1) exceeding those measured in other intertidal deposits. There is some evidence that Fe and Mn reduction-oxidation cycles are coupled to the activities of live roots within the 0–40 cm depth horizon. Oxic respiration accounted for 5–12% of total carbon mineralization. Methane flux was slow and highly variable when detectable (range: 5–66 μmol CH 4 m −2 d −1). Nitrous oxide flux was also highly variable, but within the range (1.6–106.5 μmol N 2O m −2 d −1) measured in other intertidal sediments. Rates of denitrification were rapid, ranging from 1106 to 3780 μmol N 2 m −2 d −1, and equating to 11–20% of total sediment nitrogen inputs. Denitrification was supported by rapid NH 4 release within surface deposits (range: 3.6–6.1 mmol m −2 d −1). Our results support the notion that mangrove forests are net accumulation sites for sediment and associated elements within estuaries, especially Kandelia candel forests receiving significant inputs as a direct result of intense human activity along the south China coast.

Distribution of selected anthropogenic radionuclides ( 137Cs, 238Pu, 239,240Pu and 241Am) in marine sediments with emphasis on the Spitsbergen–Bear Island area

Measurements of anthropogenic radionuclides in marine sediments can provide good estimates of past and present radioactive contamination of the marine environment. The Barents Sea is one of the world's richest ocean areas, and it is therefore of major interest for Norwegian fisheries to document the levels of radioactive contamination of this and adjacent ocean areas. In this study, concentrations of 137Cs, 238Pu, 239,240Pu and 241Am were measured in marine sediments collected mainly in the Spitsbergen–Bear Island region. Additional samples collected in the deep Norwegian Sea and near the Greenland ice-edge have been included for comparison. The highest radionuclide levels were found near Spitsbergen, reaching over 50% higher than in adjacent areas. Determinations of the mineral content and particle size distribution indicate a relation between the content of clay minerals and radionuclide levels. The present study confirms earlier observations of elevated levels of 137Cs in sediments in the Spitsbergen–Bear Island area and documents elevated levels of 238Pu, 239,240Pu and 241Am in these sediments. Using an exponential curve fit based on determinations of unsupported 210Pb in sediment cores, sedimentation rates of 0.28, 0.05 and 0.26 cm year −1 were calculated at locations south of Spitsbergen, near the Greenland ice-edge and in the deep Norwegian Sea, respectively.

Levels of 226Ra, 210Pb and total U in fish near a Saskatchewan uranium mine and mill.

Radionuclide levels in fish from the Beaverlodge Lake area, Saskatchewan, Canada, varied significantly among lakes, species and tissues, but did not vary with fish sex or age. Fish from lakes affected by an operating uranium mine and mill had radionuclide levels one to two orders of magnitude above levels in fish from an uncontaminated control lake. Concentrations were greatest in white suckers, intermediate in lake whitefish, and low in lake trout. Skin and bone contained the highest radionuclide levels; levels in flesh were much lower. The mean ash-weight concentration of 226Ra in non-control, eviscerated, whole fish was 9.3, 1.8 and 0.8 pCi X g-1 in white suckers, lake whitefish and lake trout respectively. Mean 210Pb levels for those species were 4.0, 1.4 and 0.5 pCi X g-1, while U content was 96.8, 28.2 and 5.8 micrograms X g-1, respectively. Radium-226 content in forage fish ranged from 9.7-70 pCi X g-1. Lead-210 levels ranged from 3.9-55.0 pCi X g-1, while U levels ranged from 15-119 micrograms X g-1. Bioconcentration factors varied among sites, species and tissues. The primary radionuclide transfer pathway appears to be via sediments, either through direct contact or through food organisms. Bottom-feeding species had the highest radionuclide levels while piscivorous fish had the lowest levels. The internal dose rate to non-control fish are comparatively low; any effects are likely to occur at the genetic level.