Survey on radioactive contamination in Beijing following the Japanese Fukushima nuclear accident.

The radioactive contamination in Beijing caused by the Japanese Fukushima nuclear accident was monitored. In this research, samples of air, rainwater, surface water and vegetables in Beijing were collected and measured to estimate the radioactive contamination levels in Beijing. During the period from the 15th to the 41st day after the first emission of radioactive material (first emission) from the Japanese Fukushima nuclear power station (NPS) on 12 March 2011, obvious radioactive contamination was found in the Beijing air samples. The maximum concentration of I-131 was 5.89 mBq m(-3) in the air samples detected on the 22nd day after the first emission, and the maximum concentration of Cs-137 and Cs-134 was found on the 20th day after the first emission. Except for one sample of rainwater, no artificial radionuclides associated with Fukushima were found in surface water. The measurement results showed that there was no harm to the health of local Beijing residents.

What happened when medical staff in Beijing, China wore over-apron dosemeters?

The wearing method of personal dosemeters for medical staff changed from under to outside the operator's protective apron in April 2020. We measured the radiation dose Hp(10) for medical staff in Beijing from September 2020 to October 2021. The study population consisted of 3291 medical staff. All participants were divided into three groups. After excluding unusually low doses, the collected data higher than the detection limit involved 811 (7.8%) of 10 395 readings from 479 (14.6%) of 3291 staff. The mean equivalent dose was 1.4 mSv/3 months, with an SD of 2.3 mSv. The calculated average annual effective doses of radiation workers in the three groups after the interventional procedures from September 2020 to October 2021 ranged from 0.47 to 0.63 mSv/year, with median values of 0.32, 0.23 and 0.26 mSv/year, respectively.

YouTube Videos Related to the Fukushima Nuclear Disaster: Content Analysis.

BACKGROUND: YouTube (Alphabet Incorporated) has become the most popular video-sharing platform in the world. The Fukushima Daiichi Nuclear Power Plant (FDNPP) disaster resulted in public anxiety toward nuclear power and radiation worldwide. YouTube is an important source of information about the FDNPP disaster for the world. OBJECTIVE: This study's objectives were to examine the characteristics of YouTube videos related to the FDNPP disaster, analyze the content and comments of videos with a quantitative method, and determine which features contribute to making a video popular with audiences. This study is the first to examine FDNPP disaster-related videos on YouTube. METHODS: We searched for the term "Fukushima nuclear disaster" on YouTube on November 2, 2019. The first 60 eligible videos in the relevance, upload date, view count, and rating categories were recorded. Videos that were irrelevant, were non-English, had inappropriate words, were machine synthesized, and were <3 minutes long were excluded. In total, 111 videos met the inclusion criteria. Parameters of the videos, including the number of subscribers, length, the number of days since the video was uploaded, region, video popularity (views, views/day, likes, likes/day, dislikes, dislikes/day, comments, comments/day), the tone of the videos, the top ten comments, affiliation, whether Japanese people participated in the video, whether the video recorder visited Fukushima, whether the video contained theoretical knowledge, and whether the video contained information about the recent situation in Fukushima, were recorded. By using criteria for content and technical design, two evaluators scored videos and grouped them into the useful (score: 11-14), slightly useful (score: 6-10), and useless (score: 0-5) video categories. RESULTS: Of the 111 videos, 43 (38.7%) videos were useful, 43 (38.7%) were slightly useful, and 25 (22.5%) were useless. Useful videos had good visual and aural effects, provided vivid information on the Fukushima disaster, and had a mean score of 12 (SD 0.9). Useful videos had more views per day (P<.001), likes per day (P<.001), and comments per day (P=.02) than useless and slightly useful videos. The popularity of videos had a significant correlation with clear sounds (likes/day: P=.001; comments/day: P=.02), vivid information (likes/day: P<.001; comments/day: P=.007), understanding content (likes/day: P=.001; comments/day: P=.04). There was no significant difference in likes per day (P=.72) and comments per day (P=.11) between negative and neutral- and mixed-tone videos. Videos about the recent situation in Fukushima had more likes and comments per day. Video recorders who personally visited Fukushima Prefecture had more subscribers and received more views and likes. CONCLUSIONS: The possible features that made videos popular to the public included video quality, videos made in Fukushima, and information on the recent situation in Fukushima. During risk communication on new forms of media, health institutes should increase publicity and be more approachable to resonate with international audiences.

SHOULD WE BEGIN REGULATING THE RADIATION SAFETY OF CABINET X-RAY SYSTEMS?

Radiation measurements were conducted at 22 cabinet X-ray systems in Beijing, China, between 2015 and 2019. The median dose rates in the closed-drapes position were 0.11, 0.14, 0.12, 0.14, 0.34 and 0.17 µGy h-1 at the operator position and 5 cm from the surface of the left side, right side, top, entrance and exit, respectively. When a scattering object was passed through the entrance/exit (open-drapes position), the dose rates of eight systems ranged from 1.19 to 6.72 µGy h-1 (median: 3.75 µGy h-1). From 2015 to 2019, we monitored the personal dose equivalent Hp (10) 589 times. The personal dose equivalent of three workers exceeded 1 mSv year-1. However, the integrity of equipment shielding needs to be checked regularly to ensure safe operation. The regulation of radiation protection by employers, technician support institutes or government departments is thus warranted to limit the radiation exposure of workers and the public.

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.

Radiocesium concentrations in wild boars captured within 20 km of the Fukushima Daiichi Nuclear Power Plant.

The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in 2011 released large amounts of artificial radioactive substances into the environment. In this study, we measured the concentration of radiocesium (134Cs + 137Cs) in 213 muscle samples from wild boars (Sus scrofa) captured in Tomioka town, which is located within 20 km of the FDNPP. The results showed that 210 (98.6%) muscle samples still exceeded the regulatory radiocesium limit (100 Bq/kg) for general foods. Radiocesium (134Cs + 137Cs) levels ranged from 87.1-8,120 Bq/kg fresh mass (FM), with a median concentration of 450 Bq/kg FM. The median committed effective dose was estimated to be 0.070-0.26 µSv/day for females and 0.062-0.30 µSv/day for males. The committed effective dose for one-time ingestion of wild boar meat could be considered extremely low for residents in Tomioka. The relatively high levels of radioactivity found in this study suggest that the high variability of food sources may have led to the large accumulation of radioactive substances. These results suggest that comprehensive long-term monitoring is needed to identify risk factors affecting recovery from a nuclear disaster.

Environmental Remediation of the difficult-to-return zone in Tomioka Town, Fukushima Prefecture.

Temporal variations in ambient dose rates in a restricted area designated as "difficult-to-return" for residents of Tomioka Town, Fukushima Prefecture were evaluated in a car-borne survey during 2018-2019. The median dose rates in the "Decontaminated area" in the difficult-to-return zone decreased rapidly from 1.0 µSv/h to 0.32 µSv/h; however, the median dose rates in the "Non-decontaminated area" and "Radioactive waste storage area" fluctuated between 1.1-1.4 µSv/h and 0.46-0.61 µSv/h, respectively. The detected rate of the cesium-137 (137Cs) (137Cs-detected points per all measuring points) in the "Decontaminated area" also decreased rapidly from 64% to 6.7%, accompany with decreasing in ambient dose rates. On the other hand, the detection of 137Cs in the "Radioactive waste storage area" and "Non-decontaminated area" decreased from 53% to 17% and 93% to 88%, respectively. We confirmed that the dose rates in the Decontaminated area dramatically decreased due to decontamination work aiming to help residents return home. Moreover, the estimated external exposure dose of workers during the present survey was 0.66 mSv/y in the Decontaminated area and 0.55 mSv/y in the Radioactive waste storage area, respectively. This case of Tomioka Town within the "difficult-to-return zone" may be the first reconstruction model for evaluating environmental contamination and radiation exposure dose rates due to artificial radionuclides derived from the nuclear disaster.

Chemical content and source apportionment of 36 heavy metal analysis and health risk assessment in aerosol of Beijing.

The concentration levels of 36 airborne heavy metals and atmospheric radioactivity in total suspended particulate (TSP) samples were measured to investigate the chemical characteristics, potential sources of aerosols, and health risk in Beijing, China, from September 2016 to September 2017. The TSP concentrations varied from 6.93 to 469.18 µg/m3, with a median of 133.97 µg/m3. The order for the mean concentrations of heavy metals, known as hazardous air pollutants (HAPs), was as follows: Mn > Pb > As > Cr > Ni > Se > Cd > Co > Sb > Hg > Be; Non-Designated HAPs Metals: Ca > Fe > Mg > Al > K > Na > Zn > P > Ba > Ti > Cu > Sr > B > Sn > I > V > Rb > Ce > Mo > Cs > Th > Ag > U > Pt. The median concentration of As was higher than China air quality standard (6 ng/m3). The gross α and ß concentration levels in aerosols were (1.84 ± 1.59) mBg/m3 and (1.15 ± 0.85) mBg/m3, respectively. The enrichment factor values of Cu, Ba, B, Ce, Tl, Cs, Pb, As, Cd, Sb, Hg, Fe, Zn, Sn, I, Mo, and Ag were higher than 10, which indicated enriched results from anthropogenic sources. Pb, As, and Cd are considered to originate from multiple sources; fireworks released Ba during China spring festival; Fe, Ce, and Cs may come from stable emissions such as industrial gases. The health risks from anthropogenic metals via inhalation, ingestion, and dermal pathway were estimated on the basis of health quotient as well as the results indicated that children faced the higher risk than adults during the research period. For adults, the health risk posed by heavy metals in atmospheric particles was below the acceptable level.