Journal of environmental radioactivity最新文献

{"title":"Long-term 137Cs dynamics after decontamination of an urban pond in Fukushima Prefecture, Japan","authors":"Honoka Kurosawa ,&nbsp;Yoshifumi Wakiyama ,&nbsp;Toshihiro Wada ,&nbsp;Kenji Nanba","doi":"10.1016/j.jenvrad.2024.107573","DOIUrl":"10.1016/j.jenvrad.2024.107573","url":null,"abstract":"<div><div>¹³⁷Cs tends to accumulate in ponds and dam reservoirs because of inputs from their catchments. Ponds contaminated by the Fukushima Daiichi Nuclear Power Plant accident have since been decontaminated. However, little attention has been paid to ¹³⁷Cs accumulation after the decontamination measures, such as bottom sediment removal, especially for urban ponds with reportedly high ¹³⁷Cs concentrations in their urban catchments. This study examined long-term ¹³⁷Cs accumulation after decontamination to assess the influence of urban areas. Between 2019 and 2022, bottom sediment was collected together with inflow, pond, and outflow water at an urban pond located at Koriyama City, Fukushima Prefecture, Japan. The mean ¹³⁷Cs inventory in the bottom sediment did not change significantly after decontamination, ranging from 271 to 337 kBq/m², whereas the variability increased. A significantly positive correlation of the ¹³⁷Cs concentration with δ¹⁵N, an indicator of the source contribution to bottom sediment, was determined in the bottom sediment in 2018 but not after 2019. The correlation between the specific surface area and ¹³⁷Cs concentration in the bottom sediment was significantly positive after 2020. These results suggested higher ¹³⁷Cs concentrations at sites where particles from land hosting human activities were deposited immediately after decontamination; thereafter, ¹³⁷Cs concentrations were higher at sites of fine-particle deposition. The annual mean ¹³⁷Cs concentration in pond water was stable from 2019 to 2022. The mean-normalized ¹³⁷Cs concentrations in the suspended solids and dissolved fractions in the inflow water were 0.041 m²/kg and 21.2 × 10⁻⁵ m⁻¹, respectively. These values were higher than those reported for other aquatic environments with low-urban catchment. However, the ¹³⁷Cs load from inflows was unlikely to have been enough to increase the ¹³⁷Cs inventory in the bottom sediment, despite the high ¹³⁷Cs concentration in suspended solids. The mechanism of the persistent ¹³⁷Cs contamination in urban areas merits further investigation.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"281 ","pages":"Article 107573"},"PeriodicalIF":1.9,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142695592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Laboratory experiments and modeling of the transport of 90Sr, 137Cs, 238U, 238Pu in fractures under high flow velocity","authors":"Jun Zhu ,&nbsp;Ke Chen ,&nbsp;Tian Xie ,&nbsp;Ting Li ,&nbsp;Ting Wang ,&nbsp;Aiming Zhang ,&nbsp;Chao Chen ,&nbsp;Qiulan Zhang","doi":"10.1016/j.jenvrad.2024.107572","DOIUrl":"10.1016/j.jenvrad.2024.107572","url":null,"abstract":"<div><div>The presence of fractures in the surrounding rocks of a radioactive waste disposal repository is recognized as a potential pathway for radionuclides to enter the public domain. As is well known, radionuclides transported by groundwater exhibit increased mobility in fractures, with flow velocities significantly faster than those in the pore spaces of the surrounding rock matrix. The principal objective of this study is to investigate the mobility of ⁹⁰Sr, ¹³⁷Cs, ²³⁸U, and ²³⁸Pu in fractures and their fate in the groundwater environment. Concurrently, batch and transport experiments were conducted to determine the sorption coefficients and transport parameters of each radionuclide. The results demonstrated that the adsorption and desorption isotherms of each radionuclide could be quantitatively described using the Freundlich isotherm. The hysteresis area \"<em>S</em>\" formed by the adsorption and desorption isotherm was utilized to quantify the irreversibility of the four radionuclides on granite particles, with a ranking of ²³⁸Pu &gt; ¹³⁷Cs &gt; ⁹⁰Sr &gt; ²³⁸U. The distribution coefficients (real <em>K</em>_<em>d</em>) of the four radionuclides varied by 2-3 orders of magnitude, but the tendencies and concentrations of ⁹⁰Sr, ¹³⁷Cs, ²³⁸U, and ²³⁸Pu in the sampling holes were not significantly different. These findings suggest that it is essential to introduce the first-order rate constant (<em>α</em>_<em>ch</em>) and consider the kinetic process of adsorption to describe their migration process in granite single fractures. The sorbed concentrations of radionuclides on the surface of the upper and lower granite matrix were positively correlated with \"real <em>K</em>_<em>d</em> × <em>α</em>_<em>c</em>h × time,\" while their concentrations in water flow were opposite. The irreversibility of radionuclides is another critical factor. The greater the irreversibility of radionuclides, the more challenging it is for them to desorb, resulting in a higher sorbed concentration remaining on the surface of the granite matrix and a smaller concentration in the water flow.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"280 ","pages":"Article 107572"},"PeriodicalIF":1.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142687030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Suppression mechanism contributing to the low leaching rate of cesium from incineration bottom ash","authors":"Yasumasa Tojo,&nbsp;Mikako Ishii,&nbsp;Kazuki Tamura,&nbsp;In-Hee Hwang","doi":"10.1016/j.jenvrad.2024.107575","DOIUrl":"10.1016/j.jenvrad.2024.107575","url":null,"abstract":"<div><div>After the Fukushima Daiichi nuclear accident, municipal solid waste (MSW) contaminated with radiocesium was generated. In Japan, approximately 80% of MSW by weight has been incinerated. As consequence, radiocesium was retained in incineration residue after the accident. Among the incineration residues, fly ash with high radioactivity was transported to an interim storage facility and special treatment has been carried out. While, bottom ash with radioactivity levels of &lt;8000 Bq kg⁻¹ wet has been directly deposited in conventional MSW landfills. The radiocesium leaching from bottom ash is low, but the reason for this low leaching remains unclear. In this study, leaching tests and microscopic observations of bottom ash containing stable Cs were conducted to investigate the mechanism making Cs leaching low. It is noted that the ash used was simulated ash created from combusting refuse derived fuel (RDF) to which stable Cs was added, not real radioactive ash. Based on pH dependence testing, the Cs leaching increased as the pH decreased. The amount of Cs leached in the neutral range was 2–4% mass of the total content. Electron probe microanalysis, scanning electron microscopy, and energy-dispersive X-ray spectroscopy confirmed that certain particles in bottom ash contain concentrated Cs. These particles were found to comprise aluminum, silicon, potassium, and oxygen at their core, surrounded by concentrated Cs. Raman microscopy suggested that these particles are microcline. Co-heating of microcline with Cs carbonate led to the condensation of Cs in a manner similar to particles observed in bottom ash, and Cs was captured in a glassy substance formed on the microcline surface, which reduced the leaching of Cs.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"280 ","pages":"Article 107575"},"PeriodicalIF":1.9,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142681606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatial distribution of radon in an experimental room","authors":"Raphael Grapentin,&nbsp;Antoine Geiser,&nbsp;Roger Blaser Zürcher","doi":"10.1016/j.jenvrad.2024.107567","DOIUrl":"10.1016/j.jenvrad.2024.107567","url":null,"abstract":"<div><div>The spatial distribution of radon and the relevance of the placement of radon detectors relative to the entry path of radon-containing air in an experimental room was investigated. A radon emanation source was used from which the air was transported with a constant air flow into the room. The radon contaminated air was released under a floor element used for electrical wiring which has multiple holes connecting to the inner volume of the room. At 36 equally spaced lattice points in the room the radon activity concentration was measured with two different solid-state nuclear track detectors of type Radonova Radtrak and Radonova Rapidos. The radon exposure on the detectors was accumulated over 72 days. Additionally, an electronic measurement device of type Saphymo AlphaGUARD was used as reference. It indicated a radon exposition of 475(1)<!--> <!-->kBq <!--> <!-->h/m³. The detectors of type Radtrak had a mean exposition of 564(36)<!--> <!-->kBq <!--> <!-->h/m³ and the ones of type Rapidos 496(15)<!--> <!-->kBq <!--> <!-->h/m³. Except for one outlier both types of detector showed a homogeneous distribution of radon in the room. Therefore, we have shown that under these experimental conditions the placement of the radon detector does not significantly influence the measurement result.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"280 ","pages":"Article 107567"},"PeriodicalIF":1.9,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142643922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geological and geostatistical modeling of indoor radon concentration in buildings of İzmir Province (Western Turkey)","authors":"Mutlu Zeybek ,&nbsp;Türkan Alkan","doi":"10.1016/j.jenvrad.2024.107571","DOIUrl":"10.1016/j.jenvrad.2024.107571","url":null,"abstract":"<div><div>Radon is a carcinogenic gas that cannot be detected by the five senses and poses a significant health threat, particularly in the form of lung cancer, to individuals living in all enclosed buildings worldwide.</div><div>The aims of this study are to (1) measure Indoor Radon Concentrations (IRCs) in 117 buildings in İzmir, Turkey, (2) investigate and model the relationship between the IRCs and Geological Units (GUs) and Active Faults (AFs), and (3) compare the IRC values with the European Indoor Radon Reference Level (EIRRL) (200 Bq/m³) to identify areas that pose a potential health risk for lung cancer due to elevated Indoor Radon Levels (IRLs).</div><div>The IRCs were measured using Solid State Nuclear Track Detectors (SSNTDs) in 117 buildings. These measurements were conducted between February 2013 and March 2013. The IRCs were visualized on a map along with the GUs and AFs, and a geological cross-section was generated from the data represented on this map.</div><div>The IRCs in 117 buildings were geostatistically modeled in conjunction with AFs. Generally, the highest IRCs were found in locations proximal to AFs, with an increase in IRLs observed parallel to the AFs's directions. The highest IRC (487 Bq/m³) was recorded in a building located on alluvium derived primarily from volcanic rocks, whereas the lowest concentration (28 Bq/m³) was observed in a building situated on alluvium predominantly derived from sedimentary rocks. The statistical parameters (minimum: 28 Bq/m³, maximum: 487 Bq/m³, arithmetic mean: 210 Bq/m³) of the IRCs were established.</div><div>In İzmir, IRCs in 59 out of 117 buildings, representing approximately 50% of the sampled structures, were found to exceed the recommended EIRRL of 200 Bq/m³. It is imperative that IRCs in all enclosed buildings be regularly and periodically monitored by relevant authorities, and mitigation measures should be implemented in locations where IRLs exceed the threshold value of 200 Bq/m³.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"280 ","pages":"Article 107571"},"PeriodicalIF":1.9,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142644007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Soil-to-plant transfer factors of uranium and thorium in mining and non-mining districts of Ghana","authors":"Edward Ankapong ,&nbsp;Opoku Gyamfi ,&nbsp;Victor Agyei ,&nbsp;Matt Dodd ,&nbsp;Osei Akoto ,&nbsp;Godfred Darko","doi":"10.1016/j.jenvrad.2024.107566","DOIUrl":"10.1016/j.jenvrad.2024.107566","url":null,"abstract":"<div><div>The activity concentrations of natural radionuclides in water, soil, cassava, cocoyam and yam grown in two mining districts and a non-mining district in Ghana were determined using a high-resolution gamma spectroscopy system with high-purity germanium detector. The estimated absorbed dose for soil from Amansie, Konongo, and Mampong were 206 nGy/h, 224 nGy/h and 198 nGy/h, respectively, which were all above 60 nGy/h set by the United Nations Scientific Committee on the Effects of Atomic Radiation. The soil-to-plant transfer factors (TF) for ²³⁸U, ²³²Th, and ⁴⁰K ranged from 0.11 to 1.11, 0.03 to 2.39, and 0.03 to 22.07, respectively. The results showed that the highest TF for ²³⁸U and ²³²Th were 1.11 and 2.39, respectively in cassava. There was no significant variation in the TF of ²³⁸U and ²³²Th among the soils in the different communities. The estimated transfer factors for ²³⁸U and ²³²Th for cassava, cocoyam and yam were higher than that reported by the International Atomic Energy Agency.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"280 ","pages":"Article 107566"},"PeriodicalIF":1.9,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142639018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Indoor radon trends with building code change in two Canadian cities","authors":"Janet Gaskin ,&nbsp;Liang Grace Zhou ,&nbsp;Robert Stainforth ,&nbsp;Colin Gutcher ,&nbsp;Pawel Mekarski ,&nbsp;Roshini Kassie ,&nbsp;Karen Li ,&nbsp;Ngoc Vuong ,&nbsp;Jeff Whyte ,&nbsp;Michel Gauthier ,&nbsp;Debora Quayle","doi":"10.1016/j.jenvrad.2024.107570","DOIUrl":"10.1016/j.jenvrad.2024.107570","url":null,"abstract":"<div><div>Radon studies were conducted in two Canadian cities, in Halifax, Nova Scotia, and Winnipeg, Manitoba, to evaluate trends in indoor radon before and after the 2010 National Building Code of Canada was adopted into the legally binding provincial building codes in 2011. Participants were recruited in neighbourhoods characterized by newer housing developments. A postcard campaign in each city offered free radon testing to every house in the target areas, and free testing kits were mailed to study participants. Indoor radon measurements and house questionnaires were completed by 225 eligible participants in Halifax and 171 eligible participants in Winnipeg, using alpha-track radon detectors deployed for three months during the heating season in 2021–2022. Multivariate logistic regression analyses were conducted to evaluate the association between indoor radon and the period of construction, the area in contact with the ground, the number of storeys, the type of heating system, the water source, and the type of ventilation. These analyses were focussed on the detached study houses because the majority of the participants lived in a detached house, and significant associations were identified for the period of construction and the floor where the radon detector was located. An odds ratio of 1.91 (1.04–3.50) for the detached Halifax study houses built after 2011 was associated with having a higher than geometric mean radon concentration (p = 0.033), nearly double the likelihood. There was no evidence of significant change in the indoor radon after 2011 in the detached Winnipeg study houses. A lower likelihood – almost half - for measurement conducted on a main/upper floor compared to in the basement was associated with a radon concentration above the respective geometric mean for each city: an odds ratio of 0.48 (0.27–0.86) for the detached Halifax study houses (p = 0.012), and of 0.45 (0.32–0.64) for the detached Winnipeg study houses (p = 0.022). Radon is the second most important cause of lung cancer, after smoking, and the results of this study support strengthening the radon preventive measures required in new low-rise housing to reduce the associated lung cancer burden in Canada.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"280 ","pages":"Article 107570"},"PeriodicalIF":1.9,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142621836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Species-specific trends of plutonium, radiocesium, and potassium-40 levels in three fish species of the Yenisei river (Siberia, Russia)","authors":"Tatiana A. Zotina ,&nbsp;Michail S. Melgunov ,&nbsp;Dmitry V. Dementyev ,&nbsp;Yuliyana V. Alexandrova ,&nbsp;Anton D. Karpov","doi":"10.1016/j.jenvrad.2024.107561","DOIUrl":"10.1016/j.jenvrad.2024.107561","url":null,"abstract":"<div><div>The Yenisei is the largest river in the Northern Hemisphere receiving controlled radioactive discharges from nuclear facilities. The paper presents a comparative study of temporal trends of artificial radionuclides plutonium (^239,240Pu) and radiocesium (¹³⁷Cs), and a natural isotope of the essential macronutrient potassium (⁴⁰K) in samples of three commercial fish species (Northern pike, Baikal grayling, and Siberian dace) occupying different positions in a trophic network in the Yenisei River (Siberia, Russia). Samples of fish were caught in the Yenisei in 2011–2020 during a period of significant changes in controlled radioactive releases into the river. The study has shown no increase in plutonium concentration in fish samples within two years after the upsurge in controlled Pu discharge into the river (2018–2020). Average activity concentration of ^239,240Pu (mBq∙kg⁻¹ d.w., range, mean ± sd) in muscle of grayling (0.6–31.8, 10.9 ± 8.6) was higher (p &lt; 0.01) than in muscle of dace (1.0–4.4, 2.4 ± 1.2) and pike (1.1–11, 3.8 ± 2.9). This can be attributed to the feeding of grayling on benthic invertebrates rich in Pu. The concentration of Pu tended to increase in muscle of pike with the increasing size of the fish. Average activity concentration of ¹³⁷Cs (Bq∙kg⁻¹ d.w., range, mean ± sd) in muscle of pike, a piscivorous fish (1.8–23.4, 7.7 ± 5.1), was significantly higher (p &lt; 0.001) than the average activity concentration of ¹³⁷Cs in muscle of dace (0.7–5.7, 2.7 ± 1.6) and grayling (1.3–7.2, 2.5 ± 1.7). A similar effect was revealed for ⁴⁰K. This can be attributed to biomagnification of ¹³⁷Cs and ⁴⁰K in food chains. The results will draw a baseline for assessment of dose-dependent ecological risks for wild fish itself and fish consumers, add field-based facts to the fundamental knowledge of behavior of artificial radionuclides in freshwater food chains, and suggests a hypothesis for consequent experimental studies.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"280 ","pages":"Article 107561"},"PeriodicalIF":1.9,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142621838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical modelling for the distribution of 137Cs and 131I in the scheldt basin after a potential nuclear accident","authors":"Amit Ravindra Patil ,&nbsp;Fabricio Fiengo Perez ,&nbsp;Jonathan Lambrechts ,&nbsp;Insaf Draoui ,&nbsp;Eric Deleersnijder","doi":"10.1016/j.jenvrad.2024.107568","DOIUrl":"10.1016/j.jenvrad.2024.107568","url":null,"abstract":"<div><div>Using the discontinuous Galerkin method in the SLIM modelling framework, we study the transport in the Scheldt basin and adjacent coastal area of radionuclides possibly emitted by Doel nuclear power plant in the aftermath of an accident. The contamination pathways taken into consideration are direct liquid releases into the water and deposition via the atmosphere. In past nuclear accidents, several radionuclides were released, among which, ¹³¹I and ¹³⁷Cs were considered herein. The hydrodynamics and atmospheric conditions are selected to simulate the worst-case scenario in the domain of interest. The radionuclide deposition towards the North Sea results in ¹³¹I and ¹³⁷Cs being transported to the Belgian coastal region. In case of deposition towards the river, radioactivity from upstream tributaries can reach the estuary within days. Direct liquid releases spread downstream until the mouth of the estuary after about few weeks and extend upstream into the Scheldt River. In all cases, due to tidal influence, the estuary becomes most vulnerable, with radioactivity potentially circulating for over a month. Additionally, higher river discharge resulted in decreased radioactivity levels in the estuary.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"280 ","pages":"Article 107568"},"PeriodicalIF":1.9,"publicationDate":"2024-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142621837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of a methodology for dose assessment and estimate of amount of NORM residues disposable in a conventional landfill","authors":"G. Venoso ,&nbsp;C. Nuccetelli ,&nbsp;F. Leonardi ,&nbsp;C. Di Carlo ,&nbsp;F. Trotti ,&nbsp;R. Ugolini ,&nbsp;J. Mrdakovic Popic ,&nbsp;R. Trevisi ,&nbsp;H. Caplin ,&nbsp;D. Pérez-Sánchez ,&nbsp;L. Février ,&nbsp;L. Urso","doi":"10.1016/j.jenvrad.2024.107564","DOIUrl":"10.1016/j.jenvrad.2024.107564","url":null,"abstract":"<div><div>The final disposal of NORM wastes in conventional landfill generally determines problems of acceptance by the landfill operators, since their willingness to accept Naturally Occurring Radioactive Material (NORM) is often limited due to their concern about the radiological risks and reluctance of the local community to have at local landfills material that despite being cleared is still perceived as ‘radioactive’. In order to raise awareness among landfill operators, and also among other stakeholders on the actual radiological risk of exempted or cleared NORM wastes, it is of interest to estimate the mass of annual wastes containing NORM that can be disposed of in a landfill for conventional waste complying with the annual dose criterion of 1 mSv.</div><div>A methodology was developed considering a hypothetical homogeneous large landfill and assuming that NORM wastes are delivered with an initial activity concentration of 1 kBq kg⁻¹. The methodology uses exposure scenarios and assumptions from <em>Radiation Protection 122 Part 2</em>, the codes RESRAD-ONSITE and OFFSITE, and the most recent dose coefficients from ICRP. The exposure scenarios considered are the “worker handling NORM at an active landfill” and “members of the public living near an active landfill”, For these scenarios, screening levels (called <em>Operational Levels</em> in this work) in terms of activity concentration fulfilling the annual dose criterion of 1 mSv, for members of the public (including all ICRP age groups) and workers at a landfill, have been calculated for each decay chain segments using a generic and conservative approach. The <em>Operational Levels</em> evaluated in this work are almost independent from the landfill size and are relevant to the landfills complying the EU directive 1999/31 requirements.</div><div>The obtained Operational Levels (OL) are all higher than 1 kBq kg⁻¹, for U-238 and Th-232 series radionuclides and 10 Bq g⁻¹ for K-40, which are the general clearance levels adopted in the European Union. The estimated OLs range between 2 kBq kg⁻¹ (for Th-232sec) and about 150 kBq kg⁻¹ (for Po-210). For the U-238 decay chain, the segments with the smallest OLs values are U-238sec (OL = 2.5 kBq kg⁻¹) and Ra-226+ (OL = 3.7 kBq kg⁻¹). For Th-232 chain, the most critical segments are Th-232sec and Th-228+ (OL = 3.8 kBq kg⁻¹). As regards the mass of annual NORM wastes that can be disposed of in a conventional landfill, the levels obtained for Po-210, Pb-210+ and K-40 indicate that from the radiological point of view limitations to the annual admissible mass may occur only for large activity concentrations (i.e. 40 kBq kg⁻¹ and above). For the other segments, instead, limitations can occur for activity concentration levels in residues above 2 kBq kg⁻¹.</div></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"280 ","pages":"Article 107564"},"PeriodicalIF":1.9,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142621835","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}