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3,235
result(s) for
"Radioactive contamination"
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Radiation dose and gene expression analysis of wild boar 10 years after the Fukushima Daiichi Nuclear Plant accident
The Fukushima Daiichi Nuclear Power Plant accident led to contamination with radioactive cesium in an extensive environment in Japan in 2011. We evaluated the concentration of radioactive cesium in the skeletal muscles of 22 wild boars and the expression of
IFN-γ
,
TLR3
, and
CyclinG1
in the small intestine and compared them with those of wild boar samples collected from Hyogo prefecture. The average
137
Cs radioactivity concentration in wild boars in the ex-evacuation zone was 470 Bq/kg. Most of samples still showed radioactivity concentration that exceeded the regulatory limit for foods, but the dose remarkably decreased compared with samples just after the accident.
IFN-γ
expression was significantly higher in wild boars in the ex-evacuation zone than in samples from Hyogo prefecture.
TLR3
expression was also upregulated.
CyclinG1
expression also tended to be high. Hence, wild boars might have received some effects of low-dose radiation, and immune cells were activated to some extent. However, pathological examination revealed no inflammatory cell infiltration or pathological damage in the small intestine of wild boars in the ex-evacuation area. Long-term monitoring would be necessary, but we consider that the living body responds appropriately to a stimulus from a contaminated environment.
Journal Article
Analysis of the development trend of Chinese seafood imports from Southeast Asia after the Fukushima-Daiichi radioactive treated water discharge from Japan
Japan’s decision to discharge the Fukushima-Daiichi radioactive treated water into the Pacific Ocean has drawn widespread international concern regarding radioactive contamination of seafood and its impact on the marine ecosystem and human health. China’s seafood import trade is confronted with a potentially significant threat. In the favorable circumstances created by China’s suspension of seafood imports from Japan, This article analyzes the impact of Japan’s radioactive treated water discharge on seafood safety and human health, as well as the importance of the Chinese market in the international trade of seafood, and analyzes the seafood export data from Southeast Asian countries to China from 2018 to 2024. A significant increase in seafood exports from countries such as Indonesia, Myanmar, and the Philippines to China was observed. Conversely, there has been a notable decline in the export volumes from Vietnam and Thailand. This paper proposes some proactive strategies for Southeast Asian seafood exports to China, including actively familiarizing with China’s import regulations and standards, optimizing export strategies, cultivating a positive and favorable product image, aligning with the needs of Chinese enterprises, and ensuring food safety.
Journal Article
Safety regulations of food and water implemented in the first year following the Fukushima nuclear accident
An earthquake and tsunami of historic proportions caused massive damage across the northeastern coast of Japan on the afternoon of 11 March 2011, and the release of radionuclides from the stricken reactors of the Fukushima nuclear power plant 1 was detected early on the next morning. High levels of radioiodines and radiocesiums were detected in the topsoil and plants on 15 March 2011, so sampling of food and water for monitoring surveys began on 16 March 2011. On 17 March 2011, provisional regulation values for radioiodine, radiocesiums, uranium, plutonium and other transuranic α emitters were set to regulate the safety of radioactively contaminated food and water. On 21 March 2011, the first restrictions on distribution and consumption of contaminated items were ordered. So far, tap water, raw milk, vegetables, mushrooms, fruit, nut, seaweeds, marine invertebrates, coastal fish, freshwater fish, beef, wild animal meat, brown rice, wheat, tea leaves and other foodstuffs had been contaminated above the provisional regulation values. The provisional regulation values for radioiodine were exceeded in samples taken from 16 March 2011 to 21 May 2011, and those for radiocesiums from 18 March 2011 to date. All restrictions were imposed within 318 days after the provisional regulation values were first exceeded for each item. This paper summarizes the policy for the execution of monitoring surveys and restrictions, and the outlines of the monitoring results of 220 411 samples and the enforced restrictions predicated on the information available as of 31 March 2012.
Journal Article
Assessment of radioactive substance transfer and its ecological and health impacts on the Nasser Lake ecosystem
This study investigates the distribution, transfer, and potential ecological risks of naturally occurring radioactive materials, including radon-222 (
222
Rn), radium-226 (
226
Ra), thorium-232 (
232
Th), and potassium-40 (
40
K), in the aquatic ecosystem of Nasser Lake, Egypt. As Egypt’s largest freshwater reservoir and a critical source of drinking water and fish, Nasser Lake plays a key role in environmental stability and public health. A total of 40 environmental samples—sediment, water, aquatic plants, and fish—were collected from 10 strategically selected sites around the lake. Gamma spectroscopy using sodium iodide activated with thallium [NaI(Tl)] detectors and AlphaGUARD radon monitoring systems was employed to measure radionuclide activity concentrations. Spatial distribution patterns were analyzed using Geographic Information System (GIS) techniques to identify zones of elevated radioactivity. The highest concentrations of
226
Ra,
232
Th and
40
K were recorded in sediment samples near the High Dam, reaching 10.99 ± 0.42 Bq kg
−1
, 23.94 ± 1.91 Bq kg
−1
, and 277.38 ± 23.86 Bq kg
−1
, respectively. A strong positive correlation (Pearson’s r = 0.913) was observed between
226
Ra and
222
Rn exhalation rates, confirming that sediment accumulation significantly contributes to local radiological emissions. Bioaccumulation studies showed progressive uptake of radionuclides along the aquatic food chain, with fish exhibiting a bioaccumulation factor (BAF) of 0.74 for
226
Ra. Estimated annual radiation doses from fish consumption reached up to 6.435 microsieverts per year (µSv y
−1
), remaining below international reference levels established by the World Health Organization (WHO). However, the combination of localized contamination near the High Dam and high fish consumption in nearby communities may present long-term radiological exposure risks. These findings highlight the importance of continuous monitoring of radioactive contaminants in sediment, water, and aquatic organisms in Nasser Lake. The study also provides a transferable framework for assessing the behavior of technologically enhanced naturally occurring radioactive materials (TENORM) in freshwater environments and supports the goals of the United Nations Sustainable Development Goals (SDGs) for clean water and good health.
Journal Article
Radiological risk assessment of natural radioactivity in imported rice consumed in Ghana and its implications for food safety and public health
Rice is a staple food in many developing countries, and its role in public health has been a focus of research for decades. In Ghana, a developing country in sub-Saharan Africa, per capita rice consumption is estimated at 50 kg per person per year (2023/2024 marketing year). Meanwhile, in the same period, Ghana’s milled rice production was estimated at 1.009 million metric tons, covering about 59% of the national consumption needs. And this is while, many developing countries often lack well-defined regulatory frameworks for pre-import evaluation of critical safety parameters in food products. To bridge the consumption gap, Ghana imports a significant portion of its rice, with imports forecasted at 950,000 metric tons. Despite the significance of imported rice in the national food supply, there is a notable lack of comprehensive radiological assessments focused on these products. Therefore, this study attempts to address this gap by analyzing radioactive contaminants—radium-226, radium-228, and potassium-40 —in imported rice consumed in Ghana. A total of 50 rice samples, with an average of 10 samples per brand from 5 distinct brands were collected from major markets in Accra, Kumasi, Tamale and analyzed using gamma-ray spectrometry with a High Purity Germanium (HPGe) detector. The mean activity concentrations were 2.13 ± 0.85 Bq/kg for
226
Ra, 3.69 ± 1.47 Bq/kg for
228
Ra, and 51.82 ± 7.93 Bq/kg for
40
K, all within international safety limits. The estimated total annual effective dose for an average adult was 408.44 µSv/y well below recommended international thresholds. The excess lifetime cancer risk (ELCR) was also calculated, with results indicating a negligible impact on public health. These findings highlight the importance of continuous monitoring of radioactive contaminants in imported food products to ensure consumer safety. Additionally, the study provides critical insights for policymakers, emphasizing the need for regulatory measures to control radioactivity levels in imported foods. This research supports Ghana’s public health initiatives and alignment with global food safety standards.
Journal Article
Risk assessment of radioisotope contamination for aquatic living resources in and around Japan
Food contamination caused by radioisotopes released from the Fukushima Dai-ichi nuclear power plant is of great public concern. The contamination risk for food items should be estimated depending on the characteristics and geographic environments of each item. However, evaluating current and future risk for food items is generally difficult because of small sample sizes, high detection limits, and insufficient survey periods. We evaluated the risk for aquatic food items exceeding a threshold of the radioactive cesium in each species and location using a statistical model. Here we show that the overall contamination risk for aquatic food items is very low. Some freshwater biota, however, are still highly contaminated, particularly in Fukushima. Highly contaminated fish generally tend to have large body size and high trophic levels.
Journal Article
Radiocesium concentrations in mushrooms collected in Kawauchi Village five to eight years after the Fukushima Daiichi Nuclear Power Plant accident
Following the Fukushima Daiichi Nuclear Power Plant accident in March 2011, radionuclides such as iodine-131, cesium-134 and cesium-137 were released into environment. In this study, we collected wild mushrooms from the Kawauchi Village of Fukushima Prefecture, located less than 30 km southwest of the Fukushima nuclear power plant, to evaluate their radiocesium (134Cs+137Cs) concentrations and the risk of internal radiation exposure in local residents. 342 mushroom samples were collected from 2016 to 2019. All samples were analysed for radiocesium content by a high-purity germanium detector. Among 342 mushroom samples, 260 mushroom samples (76%) were detected the radiocesium exceeding the regulatory limit of radiocesium (100 Bq/kg for general foods in Japan). The median of committed effective dose from ingestion of wild mushrooms was in the range of 0.015-0.053 mSv in 2016, 0.0025-0.0087 mSv in 2017, 0.029-0.110 mSv in 2018 and 0.011-0.036 mSv in 2019 based on the assumption that Japanese citizens consumed wild mushrooms for 1 year. Thus, our study showed that although radiocesium is still detected in mushrooms collected in Kawauchi village even after 5 to 9 years later, the committed effective dose due to consuming mushrooms was lower than 1 mSv per year. Long-term comprehensive follow-up should monitor radiocesium concentrations in wild mushrooms to support the recovery of the community after the nuclear disaster.
Journal Article
Evaluation of the radioactive contamination in fungi genus Boletus in the region of Europe and Yunnan Province in China
Numerous species of wild-grown mushrooms are among the most vulnerable organisms for contamination with radiocesium released from a radioactive fallout. A comparison was made on radiocesium as well as the natural gamma ray-emitting radionuclide (⁴⁰K) activity concentrations in the fruiting bodies of several valued edible Boletus mushrooms collected from the region of Europe and Yunnan Province in China. Data available for the first time for Boletus edulis collected in Yunnan, China, showed a very weak contamination with ¹³⁷Cs. Radiocesium concentration activity of B. edulis samples that were collected between 2011 and 2014 in Yunnan ranged from 5.2 ± 1.7 to 10 ± 1 Bq kg⁻¹ dry matter for caps and from 4.7 ± 1.3 to 5.5 ± 1.0 Bq kg⁻¹ dry matter for stipes. The mushrooms Boletus badius, B. edulis, Boletus impolitus, Boletus luridus, Boletus pinophilus, and Boletus reticulatus collected from the European locations between 1995 and 2010 showed two to four orders of magnitude greater radioactivity from ¹³⁷Cs compared to B. edulis from Yunnan. The nuclide ⁴⁰K in B. badius was equally distributed between the caps and stipes, while for B. edulis, B. impolitus, B. luridus, B. pinophilus, and B. reticulatus, the caps were richer, and for each mushroom, activity concentration seemed to be more or less species-specific.
Journal Article