Nutraceuticals as Potential Radionuclide Decorporation Agents.

Exposure of individuals to radioactive material as a result of ingestion of contaminated food and water is an increasing public health concern. Unfortunately, there are limited treatment modalities for dealing with these types of potentially toxic exposures. Recent research suggests that many plant-based nutraceuticals may possess metal-binding properties. This preliminary study investigated the ability of genistein, curcumin, quercetin, and lentinan to bind metals considered internal contamination risks, namely cesium, uranium, cobalt, and strontium, in a variety of matrices. The efficacy of these nutraceuticals in protecting cultured cells from metal-induced toxicity was also explored. Results showed that none of the compounds bound cesium or strontium. However, genistein, curcumin, and quercetin could bind uranium. Curcumin and quercetin also bound cobalt and could also protect cultured cells from metal-induced cytotoxicity. Lentinan did not bind any of the metals tested. Metal binding was also pH dependent, with no binding observed at lower pH values. This project showed that nutraceuticals could function as chelators for metals considered internal radionuclide contamination hazards. Further investigations are required in order to determine whether these compounds will become a new nontoxic arsenal of pharmaceutical compounds with which to treat radionuclide contamination.

Estimation of Dietary Intake of Radionuclides and Effectiveness of Regulation after the Fukushima Accident and in Virtual Nuclear Power Plant Accident Scenarios.

Evaluation of radiation exposure from diet is necessary under the assumption of a virtual accident as a part of emergency preparedness. Here, we developed a model with complete consideration of the regional food trade using deposition data simulated by a transport model, and estimated the dietary intake of radionuclides and the effectiveness of regulation (e.g., restrictions on the distribution of foods) after the Fukushima accident and in virtual accident scenarios. We also evaluated the dilution factors (i.e., ratios of contaminated foods to consumed foods) and cost-effectiveness of regulation as basic information for setting regulatory values. The doses estimated under actual emission conditions were generally consistent with those observed in food-duplicate and market-basket surveys within a factor of three. Regulation of restricted food distribution resulted in reductions in the doses of 54⁻65% in the nearest large city to the nuclear power plant. The dilution factors under actual emission conditions were 4.4% for radioiodine and 2.7% for radiocesium, which are ~20 times lower than those used in the Japanese provisional regulation values after the Fukushima accident. Strict regulation worsened the cost-effectiveness for both radionuclides. This study highlights the significance and utility of the developed model for a risk analysis of emergency preparedness and regulation.

Estimation of concentration of radionuclides in skeletal muscle from blood, based on the data from abandoned animals in Fukushima.

The damage caused by the earthquake on 11 March, 2011 resulted in a serious nuclear accident in Japan. Due to the damage to the Fukushima Daiichi Nuclear Power Plant (FNPP), large amounts of radioactive substances were released into the environment. In particular, one of the largest safety concerns is radioactive cesium (134 Cs and 137 Cs). Due to the FNPP nuclear accident, a 20 km area was restricted from human activity, and various types of domestic animals were left in the zone. We collected the organs and tissues from sacrificed animals to obtain scientific data to evaluate the internal deposition of radioactive compounds. At first, we found there is a strong correlation between blood 137 Cs and organ 137 Cs with data from 44 cattle, indicating that skeletal muscle is the target organ of deposition of radioactive cesium. Second, we analyzed the relationship between blood 137 Cs and muscle 137 Cs within relatively lower radioactive concentration, suggesting that estimation of concentration of 137 Cs is possible from blood concentration of 137 Cs. Finally, we developed computer software to estimate the muscle 137 Cs concentration from blood samples. Our study contributes to the food safety of livestock products.

A method for estimating radioactive cesium concentrations in cattle blood using urine samples.

In the region contaminated by the Fukushima nuclear accident, radioactive contamination of live cattle should be checked before slaughter. In this study, we establish a precise method for estimating radioactive cesium concentrations in cattle blood using urine samples. Blood and urine samples were collected from a total of 71 cattle on two farms in the 'difficult-to-return zone'. Urine 137 Cs, specific gravity, electrical conductivity, pH, sodium, potassium, calcium, and creatinine were measured and various estimation methods for blood 137 Cs were tested. The average error rate of the estimation was 54.2% without correction. Correcting for urine creatinine, specific gravity, electrical conductivity, or potassium improved the precision of the estimation. Correcting for specific gravity using the following formula gave the most precise estimate (average error rate = 16.9%): [blood 137 Cs] = [urinary 137 Cs]/([specific gravity] - 1)/329. Urine samples are faster to measure than blood samples because urine can be obtained in larger quantities and has a higher 137 Cs concentration than blood. These advantages of urine and the estimation precision demonstrated in our study, indicate that estimation of blood 137 Cs using urine samples is a practical means of monitoring radioactive contamination in live cattle.

Radioactive cesium and potassium in cattle living in the 'zone in preparation for the lifting of the evacuation order' of the Fukushima nuclear accident.

To contribute to the reconstruction of livestock industry in Fukushima, radioactive cesium (134 Cs, 137 Cs) and potassium (4 °K) were measured in various tissues of beef cattle living in an area where the evacuation order will be lifted in the near future. Radioactive cesium concentration was less than 100 Bq/kg in most of the samples. Skeletal muscles and kidney had the highest concentrations of radioactive cesium, whereas the liver was lowest among samples, excepting blood. Radioactive cesium concentration in the sirloin, tenderloin and top round was significantly higher than that in the neck muscle. Radioactive cesium concentration in the urine was not correlated with that in the blood, but the relationship became proportional when corrected with urinary 4 °K. Distribution of 4 °K was similar but not identical to that of radioactive cesium. These results suggest that it will be possible to resume livestock production in this area after the decontamination measures are completed and the evacuation order is lifted. Contamination level of living cattle can be estimated not only by blood samples but also by urine samples. If 50-100 Bq/kg of cesium is detected in the neck muscle at a slaughterhouse, the cattle should be reinspected using a sample from different muscles.

Effects of indoor and outdoor cultivation conditions on 137 Cs concentrations in cultivated mushrooms produced after the Fukushima Daiichi Nuclear Power Plant accident.

BACKGROUND: Radiocesium (134 Cs and 137 Cs) in mushrooms has been a matter of public concern after the accident at Fukushima Daiichi Nuclear Power Plant. To minimize the internal dose by ingestion of cultivated mushrooms, the Japanese government set a guideline level with respect to the radiocesium concentration in bed-logs and mushroom beds; however, the effects of indoor and outdoor cultivation methods on radiocesium concentrations in cultivated mushrooms were not clear. RESULTS: The effects of indoor and outdoor cultivation on the radiocesium concentrations in mushroom were examined using published food monitoring data. 137 Cs concentration data in Lentinula edodes from the Aizu area in Fukushima Prefecture and seven prefectures outside Fukushima were used for the analysis. No statistically significant 137 Cs concentration differences were found between these two cultivation methods. Using detected 137 Cs data in shiitake, the geometric means from each prefecture were less than one-quarter of the standard limit (100 Bq kg-1 ) for total radiocesium under both cultivation conditions. CONCLUSION: It was suspected that re-suspended radiocesium might have been taken up by mushrooms or that radiocesium might have been absorbed into the mushrooms from the soil in the outdoor cultures. However, neither effect was significant for cultivated mushrooms in the areas examined. © 2016 Society of Chemical Industry.

The Current Limits for Radionuclides in Food in Japan.

After the TEPCO Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident, the current limits in Japan on the radionuclide contamination of food [100 Bq kg for general foods, 50 Bq kg for milk and infant foods, and 10 Bq kg for drinking water as radioactive cesium (Cs + Cs)] were established on the basis of an effective dose of 1 mSv y, consistent with international standards to mitigate the exposure of the general public to radiation. Measures that include recalling or restriction of food have been taken in cases when these limits were violated. As a result of these efforts, the actual effective doses of radioactive cesium (Cs + Cs) in foods approximately 1 y after the FDNPP accident were below 0.01 mSv y. However, there is little information on the current status of these limits in the literature, which necessitates a comprehensive review of the information that exists. In this paper, the concept behind the introduction of these limits, the methods by which they were derived, and the results of monitoring food accordingly, are reviewed. This information will be helpful in the case of a future accident, and it will also help to enhance the understanding of the current limits and to relieve the anxieties of the general public concerning radiation exposure from radionuclides in food.

Current Measures on Radioactive Contamination in Japan: A Policy Situation Analysis.

BACKGROUND: The Great East Japan Earthquake on 11th March 2011 and the subsequent Fukushima Dai-ichi nuclear power plant disaster caused radioactive contamination in the surrounding environment. In the immediate aftermath of the accident the Government of Japan placed strict measures on radio-contamination of food, and enhanced radio-contamination monitoring activities. Japan is a pilot country in the WHO Foodborne Disease Burden Epidemiology Reference Group (FERG), and through this initiative has an opportunity to report on policy affecting chemicals and toxins in the food distribution network. Nuclear accidents are extremely rare, and a policy situation analysis of the Japanese government's response to the Fukushima Dai-ichi nuclear accident is a responsibility of Japanese scientists. This study aims to assess Japan government policies to reduce radio-contamination risk and to identify strategies to strengthen food policies to ensure the best possible response to possible future radiation accidents. METHODS AND FINDINGS: We conducted a hand search of all publicly available policy documents issued by the Cabinet Office, the Food Safety Commission, the Ministry of Health, Labor and Welfare (MHLW), the Ministry of Agriculture, Forestry and Fishery (MAFF) and prefectural governments concerning food safety standards and changes to radiation and contamination standards since March 11th, 2011. We extracted information on food shipment and sales restrictions, allowable radio-contamination limits, monitoring activities and monitoring results. The standard for allowable radioactive cesium (Cs-134 and Cs-137) of 100 Bq/Kg in general food, 50 Bq/Kg in infant formula and all milk products, and 10 Bq/Kg in drinking water was enforced from April 2012 under the Food Sanitation Law, although a provisional standard on radio-contamination had been applied since the nuclear accident. Restrictions on the commercial sale and distribution of specific meat, vegetable and fish products were released for areas at risk of radioactive contamination. Monitoring of radioactive materials in food products in the prefectures has been mainly conducted before shipment to restrict the distribution of radio-contaminated foods. Between March 2011 and March 2012, 133,832 tests of non-commercial and commercial products were conducted, and 1,204 tests (0.9%) were found to violate the provisional standards. Since April 2012, 278,275 tests were conducted, and 2,372 tests (0.9%) were found to violate the revised standards. MHLW assessment of representative market baskets of foodstuffs at 15 locations throughout Japan between February and March 2014 found very low estimated dietary intake of radioactive cesium (0.0007-0.019 mSv/year), as did assessments of the contents of an average day's food. Monitoring of fisheries products in coastal areas affected by the nuclear accident found very limited and declining radio-contamination of live fish outside of Fukushima prefecture. Fisheries monitoring is of limited geographical scope and covers only certain fishes. CONCLUSIONS: Area-specific bans on production and distribution have been effective in preventing radioactive contamination in the Japanese food market. Currently there is no major concern about radioactive cesium concentrations in retail foodstuffs in Japan, and very low levels of contamination at the production and wholesale stage. However, because the residue limits and food safety policies were revised on an ad hoc, emergency basis after the nuclear accident, the monitoring procedure needs to be reviewed based on objective and scientifically rational criteria. A transparent and objective scientific framework is needed for prioritizing foodstuffs for inspection and revising Prefecture-specific restrictions. Monitoring of fishes and other seafood products in the wild should be regularized and the information made more publicly accessible, and monitoring activities expanded to identify foodstuffs that are no longer a food safety risk. Consultation with producers and consumers should be more formalized to ensure their concerns are incorporated into regular policy reviews in an appropriate and transparent manner. However, despite the limited available knowledge on best practice in food control and enforcement of provisional radio-contamination limits after the accident, current Japanese policy is sufficient to protect the Japanese public from major risk of radio-contamination from the commercial food market.

Effectiveness of Protective Activities for Rehabilitation of the Forage Lands in Russia and Belarus Contaminated as a Result of the Chernobyl Accident.

Regularities of changes in the content of (137)Cs in green fodder during the remote period after the CNPP accident depending on application of agro-technical and agrochemical activities are analyzed. It is revealed that the use of mineral fertilizers reduces receipt of (137)Cs from the soil to forage and further to a food chain. It is also established that agrochemical activities are more effective than agro-technical ones.

[Radiological Aspects of Transition of Russian Areas Affected by the Chernobyl Accident to Normal Activities].

Dynamics of radiation situation in settlements, agriculture and forestry on the Russian Federation areas af- fected by the Chernobyl accident is presented. A set of challenging problems on public radiation protection and rehabilitation of territories was determined. The main objective at a long-term period after the accident is a stage-wise return of the affected areas to normal activity without any radiological criteria restrictions. For practical realization of this process it is necessary to change the national statutes and regulations consid- ering the contemporary international approaches, to pass to the current exposure situation and to establish reference levels, to define criteria of transition of the areas affected after the Chernobyl accident to normal activity. The change of conceptual approaches will allow one to revise the boundaries of settlement zoning and to develop the regulatory framework on procedures of changing their status from radioactively contami- nated zone to normal activity zone; to develop the regulatory framework on the procedures of transition of agricultural and forest lands classified as radioactively contaminated zones to territories where the traditional husbandry is possible. The Russian Federation has positive experience of transition of areas contaminated as a result of the Chernobyl accident to normal activity.

Software development for estimating the concentration of radioactive cesium in the skeletal muscles of cattle from blood samples.

The 2011 earthquake severely damaged the Fukushima Daiichi Nuclear Power Plant (FNPP), resulting in the release of large quantities of radioactive material into the environment. The deposition of these radionuclides in rice straw as livestock feed led to the circulation of contaminated beef in the market. Based on the safety concern of the consumers, a reliable method for estimating concentrations of radioactive cesium in muscle tissue is needed. In this study, we analyzed the concentrations of radioactive cesium in the blood and skeletal muscle of 88 cattle, and detected a linear correlation between them. We then developed software that can be used to estimate radioactive cesium concentrations in muscle tissue from blood samples. Distribution of this software to the livestock production field would allow us to easily identify high-risk cattle, which would be beyond the safety regulation, before shipping out to the market. This software is planned to be released as freeware. This software would contribute to food safety, and aid the recovery of the livestock industry from the damage creacted by the 2011 Tohoku earthquake and tsunami.

A discussion on the benefits of radiological food guidelines under normal conditions.

Most existing guidelines to control radionuclides in commercial food were established for nuclear emergency or post-emergency situations. They provide guideline levels only for those radionuclides representative of a nuclear or radiological emergency. Under normal conditions, naturally occurring radionuclides in food could be the main concern for radiological protection and food safety. From the perspective of radiological protection and food safety, guidelines to control radionuclides in foodstuffs are needed in non-emergency situations. The WHO's drinking water guidelines are a good example of radiological guidelines for non-emergency situations which address man-made radionuclides as well as naturally occurring radionuclides. Food safety should meet the same or comparable standards as the standards for drinking water quality. Benefits of having radiological guidelines for commercial food, some practical considerations and proposed criteria to set such guidelines for three food categories are discussed here.

Radiological risks of neutron interrogation of food.

In recent years there has been growing interest in the use of neutron scanning techniques for security. Neutron techniques with a range of energy spectra including thermal, white and fast neutrons have been shown to work in different scenarios. As international interest in neutron scanning increases the risk of activating cargo, especially foodstuffs must be considered. There has been a limited amount of research into the activation of foods by neutron beams and we have sought to improve the amount of information available. In this paper we show that for three important metrics; activity, ingestion dose and Time to Background there is a strong dependence on the food being irradiated and a weak dependence on the energy of irradiation. Previous studies into activation used results based on irradiation of pharmaceuticals as the basis for research into activation of food. The earlier work reports that (24)Na production is the dominant threat which motivated the search for (24)Na(n,γ)(24)Na in highly salted foods. We show that (42)K can be more significant than (24)Na in low sodium foods such as Bananas and Potatoes.

Collaboration of local government and experts responding to increase in environmental radiation level due to the nuclear disaster: focusing on their activities and latest radiological discussion.

Activities were introduced in Kashiwa city in the Tokyo metropolitan area to correspond to the elevated environmental radiation level after the disaster of the Fukushima Daiichi nuclear power plant. These were based on a strong cooperation between local governments and experts. Ambient dose rate and radioactivity of foodstuff produced inside of the city have been monitored. Representative ambient dose rates around living environments have almost already become their original levels of the pre-accident because of the decontamination activity, natural washout and effective half-lives of radioactivity. The internal annual dose due to radioactive cesium under the policy of 'Local Production for Local Consumption' is estimated as extremely low comparing the variation range due to natural radioactivity. Systematic survey around a retention basin has been started. All of these latest monitoring data would be one of the core information for the policy making as well as a cost-benefit discussion and risk communication.

Sample size allocation for food item radiation monitoring and safety inspection.

The objective of this study is to identify a procedure for determining sample size allocation for food radiation inspections of more than one food item to minimize the potential risk to consumers of internal radiation exposure. We consider a simplified case of food radiation monitoring and safety inspection in which a risk manager is required to monitor two food items, milk and spinach, in a contaminated area. Three protocols for food radiation monitoring with different sample size allocations were assessed by simulating random sampling and inspections of milk and spinach in a conceptual monitoring site. Distributions of (131)I and radiocesium concentrations were determined in reference to (131)I and radiocesium concentrations detected in Fukushima prefecture, Japan, for March and April 2011. The results of the simulations suggested that a protocol that allocates sample size to milk and spinach based on the estimation of (131)I and radiocesium concentrations using the apparent decay rate constants sequentially calculated from past monitoring data can most effectively minimize the potential risks of internal radiation exposure.

Cesium radioactivity in peripheral blood is linearly correlated to that in skeletal muscle: analyses of cattle within the evacuation zone of the Fukushima Daiichi Nuclear Power Plant.

The accident at the Fukushima Daiichi Nuclear Power Plant (FNPP) released a large amount of radioactive substances into the environment. Furthermore, beef contaminated with radioactive cesium above the 500 Bq/kg safety standard was circulated in the food chain in 2011. Japanese consumers remain concerned about the safety of radioactively contaminated food. In our previous study, we detected a linear correlation between radioactive cesium ((137) Cs) activity in blood and muscle around 500 to 2500 Bq/kg in cattle. However, it was unclear whether the correlation was maintained at a lower radioactivity close to the current safety standard of 100 Bq/kg. In this study, we evaluated 17 cattle in the FNPP evacuation zone that had a (137) Cs blood level less than 10 Bq/kg. The results showed a linear correlation between blood (137) Cs and muscle (137) Cs (Y = 28.0X, R(2) = 0.590) at low radioactivity concentration, indicating that cesium radioactivity in the muscle can be estimated from blood radioactivity. This technique would be useful in detecting high-risk cattle before they enter the market, and will contribute to food safety.

Distribution of radioactive cesium and stable cesium in cattle kept on a highly contaminated area of Fukushima nuclear accident.

Radioactivity inspection of slaughtered cattle is generally conducted using a portion of the neck muscle; however, there is limited information about the distribution of radioactive cesium in cattle. In this study, therefore, we measured not only radioactive cesium but also stable cesium in various tissues of 19 cattle that had been kept in the area highly contaminated by the Fukushima nuclear accident. Skeletal muscles showed approximately 1.5-3.0 times higher concentration of radioactive cesium than internal organs. Radioactive cesium concentration in the tenderloin and top round was about 1.2 times as high as that in the neck muscle. The kidney showed the highest concentration of radioactive cesium among internal organs, whereas the liver was lowest. Radioactive cesium concentration in the blood was about 8% of that in the neck muscle. Characteristics of stable cesium distribution were almost the same as those of radioactive cesium. Correlation coefficient between radioactive cesium and stable cesium in tissues of individual cattle was 0.981 ± 0.012. When a suspicious level near 100 Bq/kg is detected in the neck of slaughtered cattle, re-inspection should be conducted using a different region of muscle, for example top round, to prevent marketing of beef that violates the Food Sanitation Act.

[Reduction of 137caesium contamination in wild boars by supplementing offered food with ammonium-iron-hexa-cyanoferrate]. / Reduktion der 137Cäsium-Aktivität in Wildschweinen durch Zusatz von Ammonium-Eisen-Hexacyanoferrat ("Berliner Blau") zum Kirrfutter.

OBJECTIVE: This replication study investigated whether the 137caesium (137Cs) contamination of wild boars could be relevantly reduced under field conditions by adding ammonium-iron-hexa-cyanoferrate (AFCF; Prussian blue) to the food. MATERIAL AND METHODS: In 285 wild boars that had been shot in six Bavarian hunting territories during the season (November until May) between 01 November 2010 and 10 December 2011 137Cs contamination was analysed. Thirty-five animals originated from two hunting territories in which offered food had been supplemented with 1250 mg AFCF per kilogram food. RESULTS: The control animals showed a mean 137Cs contamination of 522 Bq/kg lean skeletal muscle meat. Direct (univariable) comparisons of the two experimental territories with the four control territories yielded a mean reduction in 137Cs contamination due to Prussian bluefeeding by -211 Bq/kg (p < 0.001). Multivariable models that took potential confounders into account (age, weight, sex, hunting date, territory) estimated the effect to be -344 Bq/kg (p < 0.05). CONCLUSION AND CLINICAL RELEVANCE: This replication study confirmed the finding of Kienzle et al. (12) who described a statistically significant reduction in 137Cs contamination by -380 Bq/kg due to the feeding of Prussian blue in other territories.

[Reduction of radioactive cesium content in beef by soaking in seasoning].

It is important to obtain information about ways of removing radioactive cesium from foods in order to reduce internal radiation exposure from food and to ensure the safety and security of food. In this study, we investigated the change of radioactive cesium content in beef due to soaking in seasoning. Our results revealed that soaking beef in liquid seasoning (salt concentration: 8-10%) for 24 h or in miso seasoning (salt concentration: about 9%) for 7 days decreased the radioactive cesium content by about 20% and 55%, respectively, compared with that present in beef before soaking. Furthermore, soaking beef in 10% salt solution for 7 days while changing the salt solution every day or every three days decreased the radioactive cesium content by about 75%, compared with that present in beef before soaking. Because the seasoning is usually discarded after soaking, the procedure of soaking beef in seasoning is a useful method of reducing the burden of radioactive cesium.