Bomb 137Cs in modern honey reveals a regional soil control on pollutant cycling by plants

Disproportionately High Contributions of 60 Year Old Weapons-137Cs Explain the Persistence of Radioactive Contamination in Bavarian Wild Boars

Radionuclides released from nuclear accidents or explosions pose long-term threats to ecosystem health. A prominent example is wild boar contamination in central Europe, which is notorious for its persistently high 137Cs levels. However, without reliable source identification, the origin of this decades old problem has been uncertain. Here, we target radiocesium contamination in wild boars from Bavaria. Our samples (2019-2021) range from 370 to 15,000 Bq·kg-1 137Cs, thus exceeding the regulatory limits (600 Bq·kg-1) by a factor of up to 25. Using an emerging nuclear forensic fingerprint, 135Cs/137Cs, we distinguished various radiocesium source legacies in their source composition. All samples exhibit signatures of mixing of Chornobyl and nuclear weapons fallout, with 135Cs/137Cs ratios ranging from 0.67 to 1.97. Although Chornobyl has been widely believed to be the prime source of 137Cs in wild boars, we find that "old" 137Cs from weapons fallout significantly contributes to the total level (10-68%) in those specimens that exceeded the regulatory limit. In some cases, weapons-137Cs alone can lead to exceedances of the regulatory limit, especially in samples with a relatively low total 137Cs level. Our findings demonstrate that the superposition of older and newer legacies of 137Cs can vastly surpass the impact of any singular yet dominant source and thus highlight the critical role of historical releases of 137Cs in current environmental pollution challenges.

Anthropogenic uranium signatures in turtles, tortoises, and sea turtles from nuclear sites

Chelonians (turtles, tortoises, and sea turtles) grow scute keratin in sequential layers over time. Once formed, scute keratin acts as an inert reservoir of environmental information. For chelonians inhabiting areas with legacy or modern nuclear activities, their scute has the potential to act as a time-stamped record of radionuclide contamination in the environment. Here, we measure bulk (i.e. homogenized scute) and sequential samples of chelonian scute from the Republic of the Marshall Islands and throughout the United States of America, including at the Barry M. Goldwater Air Force Range, southwestern Utah, the Savannah River Site, and the Oak Ridge Reservation. We identify legacy uranium (235U and 236U) contamination in bulk and sequential chelonian scute that matches known nuclear histories at these locations during the 20th century. Our results confirm that chelonians bioaccumulate uranium radionuclides and do so sequentially over time. This technique provides both a time series approach for reconstructing nuclear histories from significant past and present contexts throughout the world and the ability to use chelonians for long-term environmental monitoring programs (e.g. sea turtles at Enewetok and Bikini Atolls in the Republic of the Marshall Islands and in Japan near the Fukushima Daiichi reactors).

Interactions between micaceous minerals weathering and cesium adsorption

The environmental behavior of radioactive cesium (RCs) in contaminated areas is generally governed by soil and sediment components and natural weathering conditions. In this study, desorption tests and spectroscopic approaches were used to explore the interaction between the weathering of micaceous minerals (i.e., biotite and phlogopite) and the adsorption of Cs⁺ and the critical role of weathering in the environmental behavior of RCs. Results showed that the reaction sequence between weathering and Cs⁺ adsorption significantly affected the surface species of Cs⁺ and the structure of biotite and phlogopite. Regardless of whether it occurred before, after, or during Cs⁺ adsorption, weathering generated more high-affinity adsorption sites, namely, interlayer sites (ITs) and frayed edge sites (FESs), to different extents, and then facilitated the uptake of Cs⁺ at FESs and ITs on micaceous minerals in a poorly exchangeable state. Cs⁺ stabilized the micaceous mineral structure once it was absorbed within collapsed interlayers by hindering cation exchange and preventing further destruction during weathering. As important weathering factors, high temperature and Ca²⁺ content promoted the binding of Cs⁺ in the interlayers of biotite and phlogopite by enhancing interlayer cation exchange. These findings are beneficial for a better understanding of the environmental behaviors of RCs in the hydrosphere and pedosphere.

Discovery of the radio-protecting effect of Ecliptae Herba, its constituents and targeting p53-mediated apoptosis in vitro and in vivo

Radiation protection drugs are often accompanied by toxicity, even amifostine, which has been the dominant radio-protecting drug for nearly 30 years. Furthermore, there is no therapeutic drug for radiation-induced intestinal injury (RIII). This paper intends to find a safe and effective radio-protecting ingredient from natural sources. The radio-protecting effect of Ecliptae Herba (EHE) was discovered preliminarily by antioxidant experiments and the mouse survival rate after ¹³⁷Cs irradiation. EHE components and blood substances in vivo were identified through UPLC‒Q-TOF. The correlation network of "natural components in EHE-constituents migrating to blood-targets-pathways" was established to predict the active components and pathways. The binding force between potential active components and targets was studied by molecular docking, and the mechanism was further analyzed by Western blotting, cellular thermal shift assay (CETSA), and ChIP. Additionally, the expression levels of Lgr5, Axin2, Ki67, lysozyme, caspase-3, caspase-8,8-OHdG, and p53 in the small intestine of mice were detected. It was found for the first time that EHE is active in radiation protection and that luteolin is the material basis of this protection. Luteolin is a promising candidate for RⅢ. Luteolin can inhibit the p53 signaling pathway and regulate the BAX/BCL2 ratio in the process of apoptosis. Luteolin could also regulate the expression of multitarget proteins related to the same cell cycle.

Unravelling the origin of long-term stability for Cs+ and Sr2+ solidification inside sodalite

Cesium (Cs⁺) and strontium (Sr²⁺) ions are the main fission byproducts in the reprocessing of spent nuclear fuels for nuclear power plants. Their long half-live period (30.17 years for ¹³⁷Cs and 28.80 years for ⁹⁰Sr) makes them very dangerous radionuclides. Hence the solidification of Cs⁺ and Sr²⁺ is of paramount importance for preventing them from entering the human food chain through water. Despite tremendous efforts for solidification, the long-term stability remains a great challenge due to the experimental limitation and lack of good evaluation indicators for such long half-life radionuclides. Using density functional theory (DFT), we investigate the origin of long-term stability for the solidification of Cs⁺ and Sr²⁺ inside sodalite and establish that the exchange energy and the diffusion barrier play an important role in gaining the long-term stability both thermodynamically and kinetically. The acidity/basicity, solvation, temperature, and diffusion effect are comprehensively studied. It is found that solidification of Cs⁺ and Sr²⁺ is mainly attributed to the solvation effect, zeolitic adsorption ability, and diffusion barriers. The present study provides theoretical evidence to use geopolymers to adsorb Cs⁺ and Sr²⁺ and convert the adsorbed geopolymers to zeolites to achieve solidification of Cs⁺ and Sr²⁺ with long-term stability.

Ultralow-cost portable device for cesium detection via perovskite fluorescence

Public anxiety and concern from cesium pollution in oceans have been back on the agenda since tons of nuclear waste water were announced to be poured into oceans. Cesium ion can easily enter organisms and bioaccumulate in animals and plants, thus its harm is chronic to humans through food chains. Here we showed a kind of hybrid ionic liquid membrane (HILM) for detection of cesium ion in seawater through CsPbBr₃ perovskite fluorescence. With sustainability in mind, HILM was built frugally. The lowest cost of HILM is below 3 cents per piece. The HILM can detect cesium ion quickly with eye-readable fluorescence signal. Ultracheap, portable, easy-to-use on-site detection device could offer benefit for personal security and applications in environment science and ecology in the future decades.

Rape, sunflower and forest honeys for long-term environmental monitoring: Presence of indicator elements and non-photosynthetic carbon in old Hungarian samples

In this paper, we present the time-dependent elemental composition and AMS radiocarbon dating results of 36 rape, sunflower and forest honey samples, collected between 1985 and 2018 in geographically close locations. Based on the elemental information, we conclude that bee products regardless the type provide useful environmental information of the previous decades, such as the decreasing trend of airborne Pb emission can be traced. However, radiocarbon results agree less with the atmospheric bomb peak. Random offsets were observed in the specific radiocarbon activity of the honey samples indicating that rape, sunflower and forest honey samples are not as reliable materials for radiocarbon dating as acacia honeys. The radiocarbon results show that the rape, sunflower and forest honey samples can contain non-photosynthetic carbon, presumably derived from the soil. Thus, the complex application of honey samples for environmental reconstruction requires the species-separated investigation of bee products to reveal their adaptability for assessment approaches.

Review of harmful chemical pollutants of environmental origin in honey and bee products

Honey is a natural food with many pro-health properties, which comprises a wide variety of valuable ingredients. It can also be the source of chemical contaminants of environmental origin, including POPs that can contribute to adverse health effects to human. Monitoring the degree of pollution of honey/bee products with hazardous chemicals is important from a nutraceutical point of view. In the present work, overview of recent literature data on chemical pollutants in honey/bee products originating from the environment was performed. Their MLs, MRLs and EDI were discussed. It can be concluded that huge amount of research concerned on the presence of TMs and pesticides in honey. Most of the studies have shown that honey/bee products sampled from urban and industrialized areas were more contaminated than these sampled from ecological and rural locations. More pollutants were usually detected in propolis and bee pollen than in honey. Based on their research and regulations, authors stated, that most of the toxic pollutants of environmental origin in honey/bee products are at levels that do not pose a threat to the health of the potential consumer. The greatest concern relates to pesticides and TMs, because in some research MLs in individual samples were highly exceeded.

Cesium in Biology, Pancreatic Cancer, and Controversy in High and Low Radiation Exposure Damage-Scientific, Environmental, Geopolitical, and Economic Aspects

Radionuclide contamination in terrestrial ecosystems has reached a dangerous level. The major artificial radionuclide present in the environment is cesium-137 (137-Cs). In humans, animals, and plants cesium ion (Cs+) behaves like potassium ion (K+) and it is localized mainly inside the cells. Pancreas and salivary glands secrete Cs in the intestine thus eliminating about 14% of ingested Cs with the feces, the remaining 86% is eliminated by the kidney with the urine. Ingested radiocesium can also cause in humans several cases of pancreatitis with secondary diabetes (type 3c), which are both on the rise in the world. The Author studied the correlation between the geographical map of mortality from pancreatic cancer (PC) and the map of nuclear plant accidents, atomic bomb testing, and radioactive fallout. The worldwide death rate of PC is increasing, but the exact cause is still not known. Published data in medical literature at World, European and Italian levels are reviewed and compared. 137-Cs, with a half-life of about 30 years, is still present in the environment for about 300-600 years. Autoradiographic studies in mice have shown that 137-Cs is concentrated in greater quantity in the pancreas, particularly in exocrine cells, where most malignant PCs originate. Some methods of radiocesium removal and PC prevention are also suggested. But there is still a persistent, and not entirely disinterested, the controversy between damage from high and low exposure to ionizing radiations.