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Temporal changes of radiocesium in irrigated paddy fields and its accumulation in rice plants in Fukushima
2016
Yang, Baolu | Onda, Yūichi | Wakiyama, Yoshifumi | Yoshimura, Kazuya | Sekimoto, Hitoshi | Ha, Yiming
About half of the total paddy field area, which is the dominant agricultural land in Fukushima Prefecture, was contaminated by radiocesium released by the Fukushima Daiichi Nuclear Power Plant accident. In this study, we investigated the temporal changes of radiocesium in soil, irrigation water, and rice plant in two adjacent rice paddies, with and without surface-soil-removal, in Fukushima Prefecture for over three years (2012–2014) after the nuclear accident. Our results showed that radiocesium migrated into 24–28 cm soil layers and that the activity concentration of radiocesium in paddy soils showed a significant reduction in 2014. The newly added radiocesium to paddies through irrigation water contributed only a maximum value of 0.15% and 0.75% of the total amount present in control and decontaminated paddies, respectively, throughout the study period. The radiocesium activity concentration in suspended sediment in irrigation water exponentially decreased, and the effective half-lives (Teff) for ¹³⁷Cs and ¹³⁴Cs were 1.3 and 0.9 years, respectively. Additionally, the average suspended sediment concentration in irrigation water increased between 2012 and 2014, suggesting that enhanced soil erosion had occurred in the surrounding environment. Radiocesium accumulation in rice plant also decreased with time in both paddies. However, the concentration ratio of radiocesium for rice plant in the decontaminated paddy increased compared with control paddy, despite approximately 96% of fallout radiocesium removed in paddy soil. Further analysis is required to clarify the reasons of high concentration ratio of radiocesium for rice plant in the decontaminated paddy.
Показать больше [+] Меньше [-]Composition and depth distribution of hydrocarbons in Barataria Bay marsh sediments after the Deepwater Horizon oil spill
2016
Dincer Kırman, Zeynep | Sericano, José L. | Wade, Terry L. | Bianchi, Thomas S. | Marcantonio, Franco | Kolker, Alexander S.
In 2010, an estimate 4.1 million barrels of oil were accidentally released into the Gulf of Mexico (GoM) during the Deepwater Horizon (DWH) Oil Spill. One and a half years after this incident, a set of subtidal and intertidal marsh sediment cores were collected from five stations in Barataria Bay, Louisiana, USA, and analyzed to determine the spatial and vertical distributions and source of hydrocarbon residues based on their chemical composition. An archived core, collected before the DWH oil spill from the same area, was also analyzed to assess the pre-spill hydrocarbon distribution in the area. Analyses of aliphatic hydrocarbons, polycyclic aromatic hydrocarbons (PAHs) and stable carbon isotope showed that the distribution of petroleum hydrocarbons in Barataria Bay was patchy and limited in areal extent. Significant TPH and ΣPAH concentrations (77,399 μg/g and 219,065 ng/g, respectively) were detected in the surface sediments of one core (i.e., core A) to a depth of 9 cm. Based on a sedimentation rate of 0.39 cm yr−1, determined using 137Cs, the presence of anthropogenic hydrocarbons in these sediment core deposited ca. 50 to 60 years ago. The historical background hydrocarbon concentrations increased significantly at the sediment surface and can be attributed to recent inputs. Although the oil present in the bay's sediments has undergone moderate weathering, biomarker analyses performed on core A samples likely indicated the presence of hydrocarbons from the DWH oil spill. The effects of oiling events on Barataria Bay and other marsh ecosystems in this region remain uncertain, as oil undergoes weathering changes over time.
Показать больше [+] Меньше [-]Different cesium-137 transfers to forest and stream ecosystems
2016
Sakai, Masaru | Gomi, Takashi | Negishi, Junjiro N. | Iwamoto, Aimu | Okada, Kengo
Understanding the mechanisms of ¹³⁷Cs movement across different ecosystems is crucial for projecting the environmental impact and management of nuclear contamination events. Here, we report differential movement of ¹³⁷Cs in adjacent forest and stream ecosystems. The food webs of the forest and stream ecosystems in our study were similar, in that they were both dominated by detrital-based food webs and the basal energy source was terrestrial litter. However, the concentration of ¹³⁷Cs in stream litter was significantly lower than in forest litter, the result of ¹³⁷Cs leaching from litter in stream water. The difference in ¹³⁷Cs concentrations between the two types of litter was reflected in the ¹³⁷Cs concentrations in the animal community. While the importance of ¹³⁷Cs fallout and the associated transfer to food webs has been well studied, research has been primarily limited to cases in a single ecosystem. Our results indicate that there are differences in the flow of ¹³⁷Cs through terrestrial and aquatic ecosystems, and that ¹³⁷Cs concentrations are reduced in both basal food resources and higher trophic animals in aquatic systems, where primary production is subsidized by a neighboring terrestrial ecosystem.
Показать больше [+] Меньше [-]Trace elements in hazardous mineral fibres
2016
Both occupational and environmental exposure to asbestos-mineral fibres can be associated with lung diseases. The pathogenic effects are related to the dimension, biopersistence and chemical composition of the fibres. In addition to the major mineral elements, mineral fibres contain trace elements and their content may play a role in fibre toxicity. To shed light on the role of trace elements in asbestos carcinogenesis, knowledge on their concentration in asbestos-mineral fibres is mandatory. It is possible that trace elements play a synergetic factor in the pathogenesis of diseases caused by the inhalation of mineral fibres. In this paper, the concentration levels of trace elements from three chrysotile samples, four amphibole asbestos samples (UICC amosite, UICC anthophyllite, UICC crocidolite and tremolite) and fibrous erionite from Jersey, Nevada (USA) were determined using inductively coupled plasma mass spectrometry (ICP-MS). For all samples, the following trace elements were measured: Li, Be, Sc, V, Cr, Mn, Co, Ni, Cu, Zn, As, Rb, Sr, Y, Sb, Cs, Ba, La, Pb, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Th, U. Their distribution in the various mineral species is thoroughly discussed.The obtained results indicate that the amount of trace metals such as Mn, Cr, Co, Ni, Cu and Zn is higher in anthophyllite and chrysotile samples, whereas the amount of rare earth elements (REE) is higher in erionite and tremolite samples. The results of this work can be useful to the pathologists and biochemists who use asbestos minerals and fibrous erionite in-vitro studies as positive cyto- and geno-toxic standard references.
Показать больше [+] Меньше [-]Natural and anthropogenic radioactivity in the environment of Kopaonik mountain, Serbia
2016
Mitrović, Branislava | Ajtić, Jelena | Lazić, Marko | Andrić, Velibor | Krstič, Nikola | Vranješ, Borjana | Vićentijević, Mihajlo
To evaluate the state of the environment in Kopaonik, a mountain in Serbia, the activity concentrations of 4 K, 226Ra, 232Th and 137Cs in five different types of environmental samples are determined by gamma ray spectrometry, and radiological hazard due to terrestrial radionuclides is calculated. The mean activity concentrations of natural radionuclides in the soil are higher than the global average. However, with an exception of two sampling locations, the external radiation hazard index is below one, implying an insignificant radiation hazard. Apart from 40K, content of the natural radionuclides is predominantly below minimum detectable activities in grass and cow milk, but not in mosses. Although 137Cs is present in the soil, grass, mosses and herbal plants, its specific activity in cow milk is below minimum detectable activity. Amongst the investigated herbal plants, Vaccinium myrtillus L. shows accumulating properties, as a high content of 137Cs is detected therein. Therefore, moderation is advised in consuming Vaccinium myrtillus L. tea.
Показать больше [+] Меньше [-]Reconstructing the Chernobyl Nuclear Power Plant (CNPP) accident 30 years after. A unique database of air concentration and deposition measurements over Europe
2016
Evangeliou, Nikolaos | Hamburger, Thomas | Talerko, Nikolai | Zibtsev, Sergey | Bondar, Yuri | Stohl, Andreas | Balkanski, Yves | Mousseau, Timothy A. | Møller, Anders P.
30 years after the Chernobyl Nuclear Power Plant (CNPP) accident, its radioactive releases still remain of great interest mainly due to the long half-lives of many radionuclides emitted. Observations from the terrestrial environment, which hosts radionuclides for many years after initial deposition, are important for health and environmental assessments. Furthermore, such measurements are the basis for validation of atmospheric transport models and can be used for constraining the still not accurately known source terms. However, although the “Atlas of cesium deposition on Europe after the Chernobyl accident” (hereafter referred to as “Atlas”) has been published since 1998, less than 1% of the direct observations of 137Cs deposition has been made publicly available. The remaining ones are neither accessible nor traceable to specific data providers and a large fraction of these data might have been lost entirely. The present paper is an effort to rescue some of the data collected over the years following the CNPP accident and make them publicly available. The database includes surface air activity concentrations and deposition observations for 131I, 134Cs and 137Cs measured and provided by Former Soviet Union authorities the years that followed the accident. Using the same interpolation tool as the official authorities, we have reconstructed a deposition map of 137Cs based on about 3% of the data used to create the Atlas map. The reconstructed deposition map is very similar to the official one, but it has the advantage that it is based exclusively on documented data sources, which are all made available within this publication. In contrast to the official map, our deposition map is therefore reproducible and all underlying data can be used also for other purposes. The efficacy of the database was proved using simulated activity concentrations and deposition of 137Cs from a Langrangian and a Euleurian transport model.
Показать больше [+] Меньше [-]Assessment of natural radioactivity and 137Cs in some coastal areas of the Saudi Arabian gulf
2016
Al-Ghamdi, H. | Al-Muqrin, A. | El-Sharkawy, A.
The levels of natural radioactivity have been investigated in some Saudi Arabian Gulf coastal areas. Sampling sites were chosen according to the presence of nearby non-nuclear industrial activities such as, the two main water desalination plants in Al Khobar and Al Jubail, and Maaden phosphate complex in Ras Al Khair, to ensure that effluents discharges into the Arabian Gulf didn't enhance radioactivity in seawater and shore sediments. Seawater samples were analyzed for radium isotopes (Ra-226 & Ra-228) and measured by gamma spectrometry using high purity germanium detector, after radiochemical separation of the isotopes by co-precipitation with MnO2. Shore sediment samples were analyzed for 226Ra, 228Ra (232Th), 4°K and 137Cs using gamma sepectrometry. A small variation was observed in the activity concentrations of the investigated radioisotopes, and the activity levels were comparable to those reported in literature. Quality assurance and methods validation were established through the efficiency calibration of the detectors, the estimation of uncertainties, the use of blanks, the analysis of standard reference materials and the intercomparison and proficiency tests. Radiological hazards were assessed, and the annual effective dose had an average value of 0.02mSv. On the basis of the current results, we may conclude that any radiological hazards to the public visiting these shores are not expected.
Показать больше [+] Меньше [-]Radiological maps in beach sands along some coastal regions of Turkey
2016
Kucukomeroglu, B. | Karadeniz, A. | Damla, N. | Yesilkanat, C.M. | Cevik, U.
In the present research, the gamma-emitting radionuclides in beach sands along the coastal regions of the Ordu, Giresun and Trabzon provinces, Turkey have been determined. The natural and anthropogenic radionuclide concentrations of the samples have been measured employing a germanium (HPGe) detector with high resolution and purity. The activity for 238U, 232Th, 40K and 137Cs of the samples were found to vary in the range from below detection limit (BDL) to 65Bq·kg−1, from BDL to 28Bq·kg−1, from 9 to 1936Bq·kg−1 and from BDL to 22Bq·kg−1, respectively. The activity concentrations were compared with those in the literature. The associated radiological hazard indices were estimated, and were compared to the internationally recommended values. The radiological map of beach sand in the surveyed area was imaged. The data presented in the study are crucial since they constitute a baseline for the radiological mapping of the region in the future.
Показать больше [+] Меньше [-]Bioaccumulation and retention kinetics of cesium in the Milkfish Chanos chanos from Jakarta Bay
2016
Prihatiningsih, Wahyu Retno | Suseno, Heny | Zamani, Neviaty P. | Soedharma, Dedy
Laboratory radiotracer experiments were conducted to study the uptake, assimilation, and retention of cesium (137Cs) in milkfish (Chanos chanos) from Jakarta Bay. In this study, we have examined the bioaccumulation and distribution of 137Cs in C. chanos obtained from 137Cs-labeled seawater and 137Cs-labeled Artemia sp. feeding. The uptake of 137Cs via seawater displayed a one-compartment model suggesting that the concentration factors of 137Cs within the milkfish (weight 2.46–9.86g) at a steady-state period were between 10.66 and 3.98mLg−1 after 10days of exposure. The depuration rate was observed to be low, with only 22.80–49.14% of 137Cs absorbed by C. chanos, which was absent 6days after exposure. By contrast, depuration occurred quickly for radiolabeled food uptake, reaching 20% of retention within 10days after exposure. Muscles and viscera of the milkfish exhibited the highest degree of end uptake and end depuration of 137Cs from seawater and feeding.
Показать больше [+] Меньше [-]Ballast water sediment elemental analysis
2016
Maglić, Lovro | Zec, Damir | Frančić, Vlado
Sediment samples from the ballast water tanks of ships calling at the port of Rijeka in the Northern Adriatic were analysed using X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS) using caesium, argon and oxygen ion beams. The research was carried out in order to determine the sediment composition and relative abundance of the dominant elements. The results indicate that the sediment samples mostly consisted of compounds that originated from the deterioration of tank plates, tank coating residues and ballast operations such as clay, silt, sand and organic materials. No significant heavy metals or highly toxic elements were found. The research revealed some advantages and significant drawbacks of using XPS and SIMS for the routine analysis of sediment composition as a decision supporting tool for ballast water and sediment management.
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