Can we remove iodine-131 from tap water in Japan by boiling? - Experimental testing in response to the Fukushima Daiichi Nuclear Power Plant accident

Safeguarding drinking water: A brief insight on characteristics, treatments and risk assessment of contamination

Water pollution stands as a critical worldwide concern, bearing extensive repercussions that extend to human health and the natural ecosystem. The sources of water pollution can be diverse, arising from natural processes and human activities and the pollutants may range from chemical and biological agents to physical and radiological contaminants. The contamination of water disrupts the natural functioning of the system, leading to both immediate and prolonged health problems. Various technologies and procedures, ranging from conventional to advanced, have been developed to eliminate water impurities, with the choice depending on the type and level of contamination. Assessing risks is a crucial element in guaranteeing the safety of drinking water. Till now, research is continuing the removal of contaminates for the sake of supplying safe drinking water. The study examined physical, inorganic, organic, biological and radiological contaminants in drinking water. It looked at where these contaminants come from, their characteristics, the impact they have and successful methods used in real-world situations to clean the contaminated water. Risk assessment methodologies associated with the use of unsafe drinking water as future directives are also taken into consideration in the present study for the benefit of public concern. The manuscript introduces a comprehensive study on water pollution, focusing on assessing and mitigating risks associated with physical, inorganic, organic, biological and radiological contaminants in drinking water, with a novel emphasis on future directives and sustainable solutions for public safety.

Parameter Values for Estimation of Internal Doses from Ingestion of Radioactive Fallout from Nuclear Detonations

ABSTRACT

This paper suggests values or probability distributions for a variety of parameters used in estimating internal doses from radioactive fallout due to ingestion of food. Parameters include those needed to assess the interception and initial retention of radionuclides by vegetation, translocation of deposited radionuclides to edible plant parts, root uptake by plants, transfer of radionuclides from vegetation into milk and meat, transfer of radionuclides into non-agricultural plants and wildlife, and transfer from food and drinking water to mother's milk (human breast milk). The paper includes discussions of the weathering half-life for contamination on plant surfaces, biological half-lives of organisms, food processing (culinary factors), and contamination of drinking water. As appropriate, and as information exists, parameter values or distributions are specific for elements, chemical forms, plant types, or other relevant characteristics. Information has been obtained from the open literature and from publications of the International Atomic Energy Agency. These values and probability distributions are intended to be generic; they should be reviewed for applicability to a given location, time period, or season of the year, as appropriate. In particular, agricultural practices and dietary habits may vary considerably both with geography and over time in a given location.

Cu/Cu2O-immobilized cellulosic filter for enhanced iodide removal from water

We developed a Cu/Cu₂O-immobilized filter-type adsorbent for efficient iodide anion removal. A cellulose filter (CF) was used as a support, and its surface was modified using acrylic acid to enhance copper immobilization. The modified filter (CF-AA) exhibited 10x higher copper adsorption than the unmodified filter. Cu/Cu₂O was prepared on CF-AA by using a simple hydrothermal method to obtain CF-AA-Cu, and the prepared Cu/Cu₂O was characterized with scanning electron microscopy/energy-dispersive spectroscopy, x-ray photoelectron spectroscopy, and thermogravimetric analysis. While CF and Cu₂O themselves exhibited limited iodide adsorption performance, CF-AA-Cu exhibited fast adsorption kinetics with a half-life of 60 min as well as a high adsorption capacity of 10.32 mg/g, as obtained using the Langmuir adsorption isotherm model. Moreover, it exhibited high selectivity for iodide when high concentrations of other anions were present. The adsorption mechanism was proved by means of material characterization before and after adsorption. The coexistence of Cu⁰, Cu⁺, and Cu²⁺ in CF-AA-Cu make it effective in broader pH conditions via the redox reaction between Cu⁰ and Cu²⁺. Overall, iodide adsorbents in the form of filters with high adsorption capacity, selectivity, and ability over a wide pH range are potentially useful for removing iodide from water.

Nanometals-Containing Polymeric Membranes for Purification Processes

A recent trend in the field of membrane research is the incorporation of nanoparticles into polymeric membranes, which could produce synergistic effects when using different types of materials. This paper discusses the effect of the introduction of different nanometals such as silver, iron, silica, aluminum, titanium, zinc, and copper and their oxides on the permeability, selectivity, hydrophilicity, conductivity, mechanical strength, thermal stability, and antiviral and antibacterial properties of polymeric membranes. The effects of nanoparticle physicochemical properties, type, size, and concentration on a membrane's intrinsic properties such as pore morphology, porosity, pore size, hydrophilicity/hydrophobicity, membrane surface charge, and roughness are discussed, and the performance of nanocomposite membranes in terms of flux permeation, contaminant rejection, and antifouling capability are reviewed. The wide range of nanocomposite membrane applications including desalination and removal of various contaminants in water-treatment processes are discussed.

Enhanced removal of iodide ions by nano Cu2O/Cu modified activated carbon from simulated wastewater with improved countercurrent two-stage adsorption

A newly developed adsorbent nano Cu₂O/Cu-modified activated carbon composite (nano Cu₂O/Cu-C) was used to remove radioactive iodide ions (I^-) from simulated wastewater. The emphasis of this research is to improve adsorption performance and obtain higher I^- removal efficiency compared with the single-stage adsorption. To fully develop the amount of adsorption by nano Cu₂O/Cu-C, and to increase the decontamination factor (DF) of I^-, an improved countercurrent two-stage adsorption (ICTA) process was introduced. In the ICTA process, measures dealing with desorption of loaded adsorbent in the stage-two adsorption were taken and more extensive application of countercurrent two-stage adsorption (CTA) process could be made after the improvement to ICTA process in this study. Furthermore, in order to analyze the process and determine the I^- concentration in the effluent, a calculation method was devised based on the Langmuir isotherm equations and adsorption accumulation principle. The mean DFs were 177, 166, and 89.7, respectively, when the initial I^- concentrations were 5.00, 10.0, and 20.0 mg/L; and the adsorbent dosage was 1.25 g/L. These results were approximately 8.76, 8.97, and 6.79 times higher, respectively, than with conventional single-stage adsorption. The experimental values of the I^- concentration were higher than the calculated ones, which could be ascribed to desorption of the residual loaded adsorbent and formation of CuI in the adsorption at stage 1. Formation of CuI in the adsorption at stage 1 was considered to be the predominant reason.

Japanese Food Data Challenge the Claimed Link between Fukushima's Releases and Recently Observed Thyroid Cancer Increase in Japan

Internal, high-dose exposure with radioiodine is known to increase the risk for thyroid cancer in children and adolescents. Ingestion of contaminated food is generally regarded a dominant route of internal exposure. We analyzed the huge data set of the post-Fukushima food monitoring campaign and deployed a conservative model for the estimation of the doses to the general public in a worst-case scenario. Our data suggest that the committed equivalent ingestion doses to the thyroids of the affected Japanese public, even in the utmost conservative approach, remained below the limit on ingestion of radioiodine in foodstuffs and beverages of 50 mSv (as thyroid equivalent dose). This level of 50 mSv is also the intervention level for the administration of stable iodine, mainly after inhalation. Our study hence suggests that, based on the food data, the internal exposure of Japanese residents was too low to cause a statistically discernible increase in thyroid cancer, even if the contribution from inhalation is taken into account. The data also indicate that the governmental efforts in the food monitoring campaign were successful and cut the thyroid doses to the public by a factor of approximately 3 compared to a scenario without any monitoring.

A Simple and Rapid Method for Reducing Radiocesium Concentrations in Wild Mushrooms ( Cantharellus and Boletus ) in the Course of Cooking

Many species of mushrooms are known accumulators of radioactive cesium (¹³⁷Cs and ¹³⁴Cs). Even years and decades after major nuclear accidents, especially those at Chernobyl and Fukushima, mushrooms exhibit high concentrations of these radionuclides. We investigated a simple method for reducing the activity of radiocesium in wild mushrooms (chanterelles, Cantharellus cibarius ; and boleti, Boletus edulis ) during cooking. The juice generated while cooking mushrooms contains a relatively high fraction of the total cesium. The amount of juice can be increased by washing the mushrooms with water prior to cooking. By removing the juice, up to 29% of the radiocesium can be easily removed from chanterelles. Because boleti have a lower affinity for cesium, activity levels were lower in boleti than in chanterelles. The fraction of radiocesium in the juice was lower in boleti than in chanterelles.

Analysis of Japanese radionuclide monitoring data of food before and after the Fukushima nuclear accident

In an unprecedented food monitoring campaign for radionuclides, the Japanese government took action to secure food safety after the Fukushima nuclear accident (Mar. 11, 2011). In this work we analyze a part of the immense data set, in particular radiocesium contaminations in food from the first year after the accident. Activity concentrations in vegetables peaked immediately after the campaign had commenced, but they decreased quickly, so that by early summer 2011 only a few samples exceeded the regulatory limits. Later, accumulating mushrooms and dried produce led to several exceedances of the limits again. Monitoring of meat started with significant delay, especially outside Fukushima prefecture. After a buildup period, contamination levels of meat peaked by July 2011 (beef). Levels then decreased quickly, but peaked again in September 2011, which was primarily due to boar meat (a known accumulator of radiocesium). Tap water was less contaminated; any restrictions for tap water were canceled by April 1, 2011. Pre-Fukushima (137)Cs and (90)Sr levels (resulting from atmospheric nuclear explosions) in food were typically lower than 0.5 Bq/kg, whereby meat was typically higher in (137)Cs and vegetarian produce was usually higher in (90)Sr. The correlation of background radiostrontium and radiocesium indicated that the regulatory assumption after the Fukushima accident of a maximum activity of (90)Sr being 10% of the respective (137)Cs concentrations may soon be at risk, as the (90)Sr/(137)Cs ratio increases with time. This should be taken into account for the current Japanese food policy as the current regulation will soon underestimate the (90)Sr content of Japanese foods.

Removal efficiency of radioactive cesium and iodine ions by a flow-type apparatus designed for electrochemically reduced water production

The Fukushima Daiichi Nuclear Power Plant accident on March 11, 2011 attracted people’s attention, with anxiety over possible radiation hazards. Immediate and long-term concerns are around protection from external and internal exposure by the liberated radionuclides. In particular, residents living in the affected regions are most concerned about ingesting contaminated foodstuffs, including drinking water. Efficient removal of radionuclides from rainwater and drinking water has been reported using several pot-type filtration devices. A currently used flow-type test apparatus is expected to simultaneously provide radionuclide elimination prior to ingestion and protection from internal exposure by accidental ingestion of radionuclides through the use of a micro-carbon carboxymethyl cartridge unit and an electrochemically reduced water production unit, respectively. However, the removability of radionuclides from contaminated tap water has not been tested to date. Thus, the current research was undertaken to assess the capability of the apparatus to remove radionuclides from artificially contaminated tap water. The results presented here demonstrate that the apparatus can reduce radioactivity levels to below the detection limit in applied tap water containing either 300 Bq/kg of ¹³⁷Cs or 150 Bq/kg of ¹²⁵I. The apparatus had a removal efficiency of over 90% for all concentration ranges of radio–cesium and –iodine tested. The results showing efficient radionuclide removability, together with previous studies on molecular hydrogen and platinum nanoparticles as reactive oxygen species scavengers, strongly suggest that the test apparatus has the potential to offer maximum safety against radionuclide-contaminated foodstuffs, including drinking water.

Behavior of medically-derived 131I in the tidal Potomac River

Iodine-131 (t1/2=8.04 d) is administered to patients for treatment of thyroid disorders, excreted by patients and discharged to surface waters via sewage effluent. Radionuclides generally behave like their stable analogs; therefore, medically-derived (131)I is useful as a transport-reaction tracer of anthropogenic inputs and the aquatic biogeochemistry of iodine. Iodine-131 was measured in Potomac River water and sediments in the vicinity of the Blue Plains Water Pollution Control Plant (WPCP), Washington, DC, USA. Concentrations measured in sewage effluent from Blue Plains WPCP and in the Potomac River suggest a relatively continuous source of this radionuclide. The range of (131)I concentrations detected in surface water was 0.076±0.006 to 6.07±0.07 Bq L(-1). Iodine-131 concentrations in sediments ranged from 1.3±0.8 to 117±2 Bq kg(-1) dry weight. Partitioning in the sewage effluent from Blue Plains and in surface waters indicated that (131)I is associated with colloidal and particulate organic material. The behavior of medically-derived (131)I in the Potomac River is consistent with the nutrient-like behavior of natural iodine in aquatic environments. After discharge to the river via sewage effluent, it is incorporated into biogenic particulate material and deposited in sediments. Solid phase sediment profiles of (131)I indicated rapid mixing or sedimentation of particulate debris and diagenetic remineralization and recycling on short time scales.

Translocation of radiocesium from stems and leaves of plants and the effect on radiocesium concentrations in newly emerged plant tissues

An accident occurred at the Fukushima Dai-ichi Nuclear Power Plant in March 2011 at which time large amounts of radionuclides were released into the atmosphere and the sea. In early May 2011, it was found that newly emerged tea (Camellia sinensis) leaves contained radiocesium, both (134)Cs and (137)Cs in some areas more than 300 km away from the Fukushima plant. To understand the mechanisms of radiocesium transfer to newly emerged tissues (shoots, leaves and fruits) of other plants in the future, radiocesium concentrations in newly emerged leaves of 14 plant species collected from the sampling areas in and near National Institute of Radiological Sciences in Chiba, Japan. The studied plant types were: (1) herbaceous plants, (2) woody plants with no old leaves at the time of the March accident, and (3) woody plants with old leaves out before the accident. About 40-50 d after the start of the accident, newly emerged leaves from woody plant with old leaves tended to show higher values than other woody or herbaceous plants. Concentrations of radiocesium in newly emerged tissues of trees decreased with time, but they did not decrease to the level of herbaceous plants. The type of the plant and presence of old leaves at the time of the heavy deposition period affected the radiocesium concentrations in newly emerged tissues.

Emergency water supply: a review of potential technologies and selection criteria

Access to safe drinking water is one of the first priorities following a disaster. However, providing drinking water to the affected population (AP) is challenging due to severe contamination and lack of access to infrastructure. An onsite treatment system for the AP is a more sustainable solution than transporting bottled water. Emergency water technologies (WTs) that are modular, mobile or portable are suitable for emergency relief. This paper reviews WTs including membrane technologies that are suitable for use in emergencies. Physical, chemical, thermal- and light-based treatment methods, and membrane technologies driven by different driving forces such as pressure, temperature and osmotic gradients are reviewed. Each WT is evaluated by ten mutually independent criteria: costs, ease of deployment, ease of use, maintenance, performance, potential acceptance, energy requirements, supply chain requirements, throughput and environmental impact. A scoring system based on these criteria is presented. A methodology for emergency WT selection based on compensatory multi-criteria analysis is developed and discussed. Finally, critical research needs are identified.