Estimation of cancer risk due to radiation exposure for some daily consumption of foods.

AIMS: Considering the increasing concern about the cancer risk caused by environmental radiological effects related to the food consumption, the study was carried out evaluate the activity concentrations and cancer risk assessments of 226 Ra,232 Th, and 40 K in 72 food samples collected from different suppliers in Tehran Province of Iran. SUBJECTS AND METHODS: The specific activity concentration was determined by means of a high-resolution high-purity germanium gamma-spectroscopy system. The collected various sample groups were wheat, rice, meat, milk, and mushroom. RESULTS: The maximum concentration of 226 Ra and 232 Th was found in the wheat sample, equal to 0.7862 Bq/kg and 0.968 Bq/kg, respectively, whereas for 40 K, it was 598.35 Bq/kg in the milk sample. The annual effective dose rate ranged from 2.47 µSv/y in mushroom to 64.66 µSv/y in rice. The average excess lifetime cancer risk (ELCR) was varied from 1.60 × 10-5 for mushroom to 4.20 × 10-4 for milk, with the total ELCR value from main daily diets 1.37 × 10-3, which was a little more than the acceptable ELCR limit of 10-3. CONCLUSIONS: The ELCR due to five main daily diets was a little more than the acceptable ELCR limit of 10-3 for radiological risk in general.

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.

Usefulness of the whole-body counter for infants and small children (BABYSCAN) as a risk communication tool after the Fukushima Daiichi nuclear power plant incident.

Responding to the radiation-related concerns of parents/guardians with infants/small children is an important public health issue for regional recovery after radioactive contamination. This study summarizes the results of a systematic internal contamination screening of infants/small children, aged 0-6 years, using BABYSCAN and individual counselling sessions with physicians about radiation concerns from 2014 to 2018 in Minamisoma City. Of 3,114 participants, no one was found to have internal contamination with radioactive caesium with a detection limit of 50 Bq/body. The questionnaire survey showed a decreasing trend of concerns about food contamination and playing outside as possible causes of internal contamination over time. Because people's concerns were diverse in counselling sessions, individual responses are required. This study showed that examinations using BABYSCAN provide an opportunity for direct dialogue between the parents/guardians of infants/small children and experts. This can be considered a model case for risk communication conducted by the local government after a radioactive contamination incident.

A statistical model for estimating the radiocesium transfer factor from soil to brown rice using the soil exchangeable potassium content.

To reduce radiocesium uptake by rice, large amounts of potassium fertilizer have been applied to paddy fields contaminated by radiocesium released from the Fukushima Dai-ichi Nuclear Power Plant owned by the Tokyo Electric Power Company. The Fukushima Prefectural Government recommended maintenance of the soil exchangeable K content up to 200 mg K kg-1 before conventional fertilization in rice production. We constructed an equation to predict the transfer factor from soil to brown rice using the soil exchangeable K content. This equation was then used to calculate the appropriate soil exchangeable K content, which ensures a low risk (5%) of brown rice exceeding the standard limit (100 Bq kg-1 for grains) established in 2012. The equations were constructed using field data obtained by an investigation (measurement of the 137Cs concentrations in soil and brown rice and measurement of the soil exchangeable K content at harvest) that was performed from 2012 to 2015 in 321 paddy fields distributed all over Fukushima Prefecture. We found that the stochastic fluctuation of the transfer factor approximately follows a lognormal distribution under the given environmental conditions. Four factors are considered in predicting the logarithmic quantity of the transfer factor: (1) the linear influence of the logarithm of the exchangeable K content in soil, (2) the non-linear influence of the logarithm of the exchangeable K content in soil, (3) three districts in the Fukushima Prefecture and (4) the year. The linear model of the logarithm of exchangeable K content in soil was adopted by the RD criterion, which indicates the absolute goodness of models for prediction. The predictive ability of the model increased by 29% after including the logarithm of the exchangeable K content in soil (factor 1), while the predictive ability further increased by 10% after including spatial and temporal information (factors 3 and 4). The validity of the exchangeable K content recommended by the Fukushima Prefectural Government was re-examined using the proposed equations, which indicated that the conventional recommendation was appropriate at 2012 but is not fully appropriate under the current situation in which the radiocesium concentration in soil has decreased.

Evaluation of abundance of artificial radionuclides in food products in South Korea and sources.

Food samples are collected nationwide from January 2016 to February 2017 and their contents of artificial radionuclides are measured to address the growing concerns regarding the radioactive contamination of food products in Korea. Specifically, 900 food samples are collected for this study and their contents of representative artificial radionuclides 134Cs, 137Cs, 239,240Pu, and 90Sr are analyzed. The analysis shows that the activity concentrations of 137Cs in fish range from minimum detectable activity (MDA) to 340 mBq/kg of fresh weight. The concentration factor (CF) determined for 137Cs as a measure of its bioavailability is calculated to be ca. 74 and found to be very similar to that (100) recommended by the International Atomic Energy Agency. With an MDA of <0.221 mBq/kg, the results reveal that 239,240Pu values in fish are below the MDA. The activity concentrations of 137Cs and 90Sr are lower than the MDA in both shellfish and seaweed, while the activity concentrations of 239,240Pu in shellfish range from 0.26 to 2.18 mBq/kg, and for seaweed samples range from 2.07 to 3.38 mBq/kg. The atom ratios of 240Pu/239Pu in shellfish caught at the Korean coast vary from 0.209 to 0.237, with a mean of 0.227. The higher 240Pu/239Pu atom ratio determined in shellfish is thought to be caused by the plutonium transported from the Pacific Proving Grounds rather than other sources such as the Fukushima nuclear power plant accident. The activity concentrations of 137Cs in mushrooms are found to vary from 1.0 to 21.4 Bq/kg, with the highest concentrations observed in the Oak (shiitake) and Sarcodon asparatus. 134Cs is detected in three mushroom specimens collected from Jeju Island and about 3-3.6% of 137Cs present in the wild mushrooms native to the Jeju Island are introduced as a result of the Fukushima nuclear plant accident. The annual effective doses of 137Cs received through consumption of mushrooms and fish are 2.0 × 10-4 mSv yr-1 and 3.9 × 10-5 mSv yr-1, and those values are negligible compared to the annual effective doses limit of 1 mSv yr-1.

Information and statistical support for retrospective study of mortality among people exposed in childhood as a result of the Chornobyl accident and living in contaminated areas of Ukraine: assessment of feasibility. / INFORMATsIY̆NO STATYSTYChNE ZABEZPEChENNIa RETROSPEKTYVNOGO DOSLIDZhENNIa SMERTNOSTI OSIB, OPROMINENYKh U DYTIaChOMU VITsI VNASLIDOK AVARIÏ NA ChORNOBYL'S'KIY̆ AES TA PROZhYVAIuChYKh NA RADIOAKTYVNO ZABRUDNENYKh TERYTORIIaKh UKRAÏNY: OTsINKA PRAKTYChNOÏ MOZhLYVOSTI.

OBJECTIVE: Analysis of information from various sources for its use in epidemiological study on mortality of people (born in 1968-1986) who were children and adolescents at the time of the Chornobyl accident. OBJECT OF STUDY: Information and statistical sources for 1986-2011 on mortality among people who were children and adolescents at the time of the Chornobyl accident and lived on the most radioactive contaminated territories (RCT) of Ukraine (Ivankiv and Polisske regions of Kyiv oblast, Narodychi and Ovruch regions of Zhytomyr oblast). RESEARCH METHODS: theoretical, general scientific, documentary analysis, demographic. RESULTS AND CONCLUSIONS: The study is to determine the suitability of available information and statistical support for measuring and assessing mortality of people exposed in childhood as a result of the Chornobyl accident and liv ing in contaminated areas of Ukraine. A combination of information and statistical data provided by SRU, Ministry of Justice of Ukraine, State Statistics Service (SSS) of Ukraine and NNCRM makes it possible to successfully conduct retrospective cohort studies in any area and for any period.

Reconstruction of individualized doses of subjects from the Ukrainian State Register - of Persons that Affected due to Chornobyl accident and reside in Korosten raion of Zhytomyr oblast. / REKONSTRUKTsIIa INDYVIDUALIZOVANYKh DOZ SUB'IeKTIV DERZhAVNOGO REIeSTRU UKRAÏNY OSIB, IaKI POSTRAZhDALY VNASLIDOK ChORNOBYL'S'KOÏ KATASTROFY, ShchO PROZhYVAIuT' V KOROSTENS'KOMU RAY̆ONI ZhYTOMYRS'KOÏ OBLASTI.

STUDY OBJECTIVE: To elaborate an ecological dosimetric model of reconstruction individualized exposure doses of subjects from the State Register of Ukraine (SRU) - of persons, affected due to Chornobyl accident and reside at the radioactive contaminated territory of Korosten raion of Zhytomyr Oblast, and to calculate exposure doses for those persons. MATERIALS AND METHODS: In the paper, an ecological dosimetric model is presented which is elaborated in order to individualize exposure doses of people who reside in Korosten raion of Zhytomyr Oblast and are registered in SRU. The model is based on the results of radio ecological and dosimetric monitoring held in the period of 1986-2013 at the territory of northern oblasts of Ukraine. Annual dose over each post accidental year consists of the two compo nents: (a) annual effective dose of external gamma exposure (due to radioactive fallout on the ground), and (b) internal exposure of the whole body (due to consumption of meal contaminated by radioactive isotopes). For 1986, the dose of internal exposure is evaluated out of all main radionuclides of radioactive accidental fallout, and after 1987 only for radioisotopes of caesium (134Cs and 137Cs). The parameterization of the model is based on the pre vious experience in working out a complex of ecological dosimetric models for estimation of referent exposure doses of Ukrainian population. RESULTS AND CONCLUSIONS: Individualized doses of external and internal exposure (annual and accumulated) are estimated for the population of various age groups that resides in the settlements of Korosten raion (totally about 100 settlements). Separately the doses are presented for rural settlements of the raion and for the city of Korosten for each year of the post accidental period of 1986-2016. Estimates of doses are given that were accumulated: (a) during 15 years just after the accident, (b) for the period of 2000-2016, and (c) for 30 year period after the acci dent. Mean dose accumulated for 30 years after the Chornobyl accident by residents of rural settlements of Korosten raion is estimated as 19.8 mSv, and for inhabitants of the Korosten city as 20.9 mSv. On condition of permanent res idence in the raion, residents of about 66 % settlements of Korosten raion accumulated the doses in the interval 5 20 mSv during 30 years after the accident. For the residents of about 25 % settlements the accumulated dose is in the interval 20-50 mSv, and for 7 % of settlements it exceeds 50 mSv.

Estimating doses from Aboriginal bush foods post-remediation of a uranium mine.

This paper presents a calculator to facilitate assessments of ingestion doses from Aboriginal bush foods. The calculator combines information on traditional diet and land use with radionuclide concentration ratios and ingestion dose coefficients to estimate doses. The calculator was applied to the planned remediation of Ranger uranium mine to derive a set of scaling factors between radionuclide activity concentrations in environmental media and ingestion dose from bush foods. The scaling factors can be used to estimate doses from bush foods once the post-remediation radiological conditions of the mine and surrounding environment are known.

Ingestion intakes of 137Cs by the Czech population: Comparison of different approaches.

Ingestion intakes of 137Cs of the Czech population were calculated in two different ways - either from the measured activity of 137Cs in components of food in combination with statistical data about consumption rates or from retention of 137Cs in the human body obtained by whole body counting or calculated from daily urinary excretion of 137Cs. Data from the time period since 1986 to 2015 are used. The daily ingestion intake was about 25 Bq d-1 in 1986 and is around 0.1 Bq d-1 at present. Both approaches of ingestion intake calculation have their advantages and disadvantages. Ingestion intake calculated from 137Cs body content was assumed to be the most accurate as it requires fewer assumptions than the calculation from food consumption. However, calculation of 137Cs intake from food consumption is an important tool for prediction doses after the release of radionuclides into environment. The best agreement exceeding the intakes from urine measurement 5 times at maximum was achieved when intakes calculated from food also included products from the natural environment. Without this, the ingestion intake could be under-predicted seriously up to 6 times, especially in the longer time after the release of 137Cs into environment. Ingestion intakes up to 11 Bq d-1 in a group of people with significant consumption of game meat containing elevated activity of 137Cs activity were included as a special case. Various groups of foodstuffs had varying effects on the total committed effective dose from 137Cs. Dose estimates for the Czech population from 137Cs ingestion intake achieved 80 µSv in 1986 and not more than 2 µSv currently and were similar to those incurred by the population of neighbouring countries.

Analysis of Natural and Anthropogenic Radionuclide Content in Palm Date Fruit of the United Arab Emirates: A Baseline Study.

The purpose of this study is to contribute to a wider effort of establishing an environmental radiation baseline for the United Arab Emirates (UAE) before the startup of the country's first nuclear reactor in 2017. An investigation of gamma-emitting radionuclide concentrations in palm dates grown in the UAE was performed. Palm date samples of 10 varieties originating from several local commercial date palm farms of the UAE were collected and analyzed. The study targeted the naturally occurring radionuclides, such as U, Th, and K, in addition to any potential anthropogenic radionuclides, such as Cs and others. Gamma spectrometry revealed measured activity concentrations for U (Ra), Th (Ra), and K that ranged from 0.61 to 0.80 Bq kg, 0.10 to 0.23 Bq kg, and 191 to 362 Bq kg, respectively, on a dry-weight basis, and calculated activity concentrations on a wet basis ranged from 0.52 to 0.69 Bq kg, 0.09 to 0.22 Bq kg, and 168 to 297 Bq kg, respectively. No Cs or other anthropogenic radionuclides could be detected in this study. All measurements were performed using a coaxial HPGe detector with 40% relative efficiency quoted by the manufacturer. Efficiency calibration correction factors were calculated using Angle software.

A review of the Fukushima nuclear reactor accident: radiation effects on the thyroid and strategies for prevention.

PURPOSE OF REVIEW: This is a summary of the nuclear accident at the Tokyo Electric Power Company Fukushima Daiichi Nuclear Power Stations (FDNPS) on 11 March 2011 to be used as a review of the radiation effects to the thyroid and strategies of prevention. RECENT FINDINGS: The amount of radioiodine released to the environment following the Fukushima accident was 120 Peta Becquerel, which is approximately one-tenth of that in the Chernobyl accident. Residents near the FDNPS were evacuated within a few days and foodstuffs were controlled within 1 or 2 weeks. Therefore, thyroid radiation doses were less than 100 mSv (intervention levels for stable iodine administration) in the majority of children, including less than 1 year olds, living in the evacuation areas. Because the incidence of childhood thyroid cancer increased in those residing near the site following the Chernobyl accident, thyroid screening of all children (0-18 years old) in the Fukushima Prefecture was started. To date, screening of more than 280 000 children has resulted in the diagnosis of thyroid cancer in 90 children (approximate incidence, 313 per million). Thus, although the dose of radiation was much lower, the incidence of thyroid cancer appears to be much higher than that following the Chernobyl accident. SUMMARY: A comparison of the thyroidal consequences following the Fukushima and Chernobyl nuclear reactor accidents is discussed. We also summarize the recent increased incidence in thyroid cancer in the Fukushima area following the accident in relation to increased thyroid ultrasound screening and the use of advanced ultrasound techniques. VIDEO ABSTRACT: http://links.lww.com/COE/A8.

Comprehensive whole-body counter surveys of Miharu-town school children for three consecutive years after the Fukushima NPP accident.

Comprehensive whole-body counter surveys covering over 93% of the school children between the ages of 6 and 15 in Miharu town, Fukushima Prefecture, have been conducted for three consecutive years, in 2011, 2012 and 2013. Although the results of a questionnaire indicate that approximately 60% of the children have been regularly eating local or home-grown rice, in 2012 and 2013 no child was found to exceed the (137)Cs detection limit of 300 Bq/body.

Radioactivity inspection of Taiwan for food products imported from Japan after the Fukushima nuclear accident.

The 3-11 Earthquake occurred in Japan last year had greatly damaged the lives and properties and also caused the core meltdown accident in the Fukushima nuclear power plant followed by the leakage of radioactive materials into biosphere. In order to protect against the detriment of radiation from foods which were imported from Japan, the Institute of Nuclear Energy Research (INER) in Taiwan started to conduct radioactivity inspection of food products from Japan after the accident. A total of about 20,000 samples had been tested from March 24 2011 to March 31 2012.

Dose estimates for the local inhabitants from 210Po ingestion via dietary sources at a proposed uranium mining site in India.

PURPOSE: To study the distribution of (210)Po activity in food in Bagjata in East Singhbhum, India. MATERIALS AND METHODS: (210)Po were analyzed in the food samples of plant origin such as cereals, pulses, fruits, vegetables and food of animal origin such fish, chicken, egg, etc., in and around Bagjata uranium mining area as a part of baseline study after acid digestion. The intake and ingestion dose of the radionuclide was estimated. RESULTS: The general range of (210)Po activity in all the dietary components ranged widely from <0.2-36 Bqkg(-1)(fresh). In the food of plant origin, the minimum activity of (210)Po was estimated in vegetables while maximum in pulses. In food of animal origin, the observed minimum activity of (210)Po was in eggs and the maximum observed was in chicken samples. The intake of (210)Po considering all dietary components was found to be 464 Bq.Y(-1) while the ingestion dose was calculated to be 557 µSv.Y(-1), respectively. The estimated doses are reflecting the natural background dose via the route of ingestion, which is much below the 1 mSv limit set in the International Commission on Radiological Protection (ICRP) recommendations. CONCLUSION: The study confirms that current levels of (210)Po do not pose a significant radiological risk to the local inhabitants.

Food safety regulations: what we learned from the Fukushima nuclear accident.

On 11 March 2011, the magnitude-9.0 earthquake and a substantial tsunami struck off the northeast coast of Japan. The Fukushima nuclear power plants were inundated and stricken, followed by radionuclide releases outside the crippled reactors. Provisional regulation values for radioactivity in food and drink were set on 17 March and were adopted from the preset index values, except that for radioiodines in water and milk ingested by infants. For radiocesiums, uranium, plutonium and transuranic α emitters, index values were defined in all food and drink not to exceed a committed effective dose of 5 mSv/year. Index values for radioiodines were defined not to exceed a committed equivalent dose to the thyroid of 50 mSv/year, and set in water, milk and some vegetables, but not in other foodstuffs. Index values were calculated as radioactive concentrations of indicator radionuclides ((131)I for radioiodines, (134)Cs and (137)Cs for radiocesiums) by postulating the relative radioactive concentration of coexisting radionuclides (e.g., (132)I, (133)I, (134)I, (135)I and (132)Te for (131)I). Surveys were thence conducted to monitor levels of (131)I, (134)Cs and (137)Cs. Provisional regulation values were exceeded in tap water, raw milk and some vegetables, and restrictions on distribution and consumption began on 21 March. Fish contaminated with radioiodines at levels of concern were then detected, so that the provisional regulation value for radioiodines in seafood adopted from that in vegetables were additionally set on 5 April. Overall, restrictions started within 25 days after the first excess in each food or drink item, and maximum levels were detected in leafy vegetables (54,100 Bq/kg for (131)I, and a total of 82,000 Bq/kg for (134)Cs and (137)Cs). This paper focuses on the logic behind such food safety regulations, and discusses its underlying issues. The outlines of the food monitoring results for 24,685 samples and the enforced restrictions will also be described.

Assessment of health safety from ingestion of natural radionuclides in seafoods from a tropical coast, India.

The activities of ²¹°Po and ²¹°Pb were determined in commonly consumed seafoods to evaluate the internal exposure and risk to humans residing Kudankulam coast where a mega nuclear power plant is under construction. The concentration of ²¹°Po in seafoods ranged from 1.2 ± 0.7 to 248 ± 8.1 Bq kg⁻¹. Meanwhile, ²¹°Pb ranged between 1.1 ± 0.05 and 14.8 ± 1.6 Bq kg⁻¹. The committed effective dose (CED) due to ²¹°Po and ²¹°Pb varied from 11.04 to 515.6 and 3.93 to 23.5 µSv yr⁻¹, respectively. The lifetime cancer risk for the public due to ²¹°Po was in the range of 3.47 × 10⁻5- 1.62 × 10⁻³ and it was 4.03 × 10⁻5 - 1.96 × 10⁻4 due to ²¹°Pb. The activity intake, effective dose and cancer risk was found lesser than international guidelines and the seafood intake was considered to be safe for human consumption.