Genetic and Somatic Effects of Carbon-14

Trophic transfer of carbon-14 from algae to zebrafish leads to its blending in biomolecules and the dysregulation of metabolism via isotope effect

Carbon-14 (C-14) has been a major contributor to the human radioactive exposure dose, as it is released into the environment from the nuclear industry in larger quantities compared to other radionuclides. This most abundant nuclide enters the biosphere as organically bound C-14 (OBC-14), posing a potential threat to public health. Yet, it remains unknown how this relatively low radiotoxic nuclide induces health risks via chemical effects, such as isotope effect. By establishing a trophic transfer model involving algae (Scenedesmus obliquus), daphnia (Daphnia magna) and zebrafish (Danio rerio), we demonstrate that rapid incorporation and transformation of inorganic C-14 by algae into OBC-14 facilitates the blending of C-14 into the biomolecules of zebrafish. We find that internalized C-14 is persistently retained in the brain of zebrafish, affecting DNA methylation and causing alterations in neuropathology. Global isotope tracing metabolomics with C-14 exposure further reveals the involvement of C-14 in various critical metabolic pathways, including one-carbon metabolism and nucleotide metabolism. We thus characterize the kinetic isotope effects for 12C/14C in the key reactions of these metabolic pathways through kinetic experiments and density functional theory computations, showing that the isotopic substitution of carbon in biochemicals regulates metabolism by disrupting reaction ratios via isotope effects. Our results suggest that inorganic C-14 discharged by the nuclear industry can be biotransformed into OBC-14 to impact metabolism via isotope effects, providing new insights into understanding the health risk of C-14, which is traditionally considered as a low radiotoxic nuclide.

Disproportionate Impacts of Radiation Exposure on Women, Children, and Pregnancy: Taking Back our Narrative

Narratives surrounding ionizing radiation have often minimized radioactivity's impact on the health of human and non-human animals and the natural environment. Many Cold War research policies, practices, and interpretations drove nuclear technology forward by institutionally obscuring empirical evidence of radiation's disproportionate and low-dose harm-a legacy we still confront. Women, children, and pregnancy development are particularly sensitive to exposure from radioactivity, suffering more damage per dose than adult males, even down to small doses, making low doses a cornerstone of concern. Evidence of compounding generational damage could indicate increased sensitivity through heritable impact. This essay examines the existing empirical evidence demonstrating these sensitivities, and how research institutions and regulatory authorities have devalued them, willingly sacrificing health in the service of maintaining and expanding nuclear technology (Nadesan 2019). Radiation's disproportionate impacts should now be the research and policy focus, as society is poised to make crucial and long-lasting decisions regarding climate change mitigation and future energy sources (Brown 2019b).

Archaeology enters the 'atomic age': a short history of radiocarbon, 1946-1960

Today, the most powerful research technique available for assigning chronometric age to human cultural objects is radiocarbon dating. Developed in the United States in the late 1940s by an alumnus of the Manhattan Project, radiocarbon dating measures the decay of the radioactive isotope carbon-14 (C14) in organic material, and calculates the time elapsed since the materials were removed from the life cycle. This paper traces the interdisciplinary collaboration between archaeology and radiochemistry that led to the successful development of radiocarbon dating in the early 1950s, following the movement of people and ideas from Willard Libby's Chicago radiocarbon laboratory to museums, universities and government labs in the United States, Australia, Denmark and New Zealand. I show how radiocarbon research built on existing technologies and networks in atomic chemistry and physics but was deeply shaped by its original private philanthropic funders and archaeologist users, and ultimately remained to the side of many contemporaneous Cold War scientific and military projects.

Reactive Neuroblastosis in Huntington's Disease: A Putative Therapeutic Target for Striatal Regeneration in the Adult Brain

The cellular and molecular mechanisms underlying the reciprocal relationship between adult neurogenesis, cognitive and motor functions have been an important focus of investigation in the establishment of effective neural replacement therapies for neurodegenerative disorders. While neuronal loss, reactive gliosis and defects in the self-repair capacity have extensively been characterized in neurodegenerative disorders, the transient excess production of neuroblasts detected in the adult striatum of animal models of Huntington's disease (HD) and in post-mortem brain of HD patients, has only marginally been addressed. This abnormal cellular response in the striatum appears to originate from the selective proliferation and ectopic migration of neuroblasts derived from the subventricular zone (SVZ). Based on and in line with the term "reactive astrogliosis", we propose to name the observed cellular event "reactive neuroblastosis". Although, the functional relevance of reactive neuroblastosis is unknown, we speculate that this process may provide support for the tissue regeneration in compensating the structural and physiological functions of the striatum in lieu of aging or of the neurodegenerative process. Thus, in this review article, we comprehend different possibilities for the regulation of striatal neurogenesis, neuroblastosis and their functional relevance in the context of HD.

The scientist's education and a civic conscience

A civic science curriculum is advocated. We discuss practical mechanisms for (and highlight the possible benefits of) addressing the relationship between scientific knowledge and civic responsibility coextensively with rigorous scientific content. As a strategy, we suggest an in-course treatment of well known (and relevant) historical and contemporary controversies among scientists over science policy or the use of sciences. The scientific content of the course is used to understand the controversy and to inform the debate while allowing students to see the role of scientists in shaping public perceptions of science and the value of scientific inquiry, discoveries and technology in society. The examples of the activism of Linus Pauling, Alfred Nobel and Joseph Rotblat as scientists and engaged citizens are cited. We discuss the role of science professors in informing the social conscience of students and consider ways in which a treatment of the function of science in society may find, coherently, a meaningful space in a science curriculum at the college level. Strategies for helping students to recognize early the crucial contributions that science can make in informing public policy and global governance are discussed.

Preparation and application of steeps of tea as new simulations of urine for the performance testing programme of 14C

(14)C is one of the radionuclides for which the Canadian Nuclear Safety Commission has developed performance testing programmes (PTPs). During the PTP exercises, clients receive samples of natural urine containing spiked radionuclides, for testing. In these programmes, urine has disadvantages. These include (1) slow collection times from donors, (2) unpleasant smell and (3) potential to transmit diseases. To assist in solving some of these problems, the Canadian National Calibration Reference Centre for Bioassay and In Vivo Monitoring has conducted research with tea solutions, to find simpler, safer and more readily available alternatives to urine. This paper provides a new technique by which steeps of black tea have been successfully prepared for the (14)C PTP. The results of tea solutions compared well with those of urine. It was concluded that tea steeps, of which the spectroscopic and colour quenching properties have been adjusted, do provide appropriate urine simulations, suitable for use in PTPs.

Evaluation of tea as a matrix in a dual (3H/14C) performance testing program in Canada

Urine is the most popular matrix used in performance testing programs (PTP) and inter-comparison programs (ICP) for bioassay. Because it comes from humans, there are concerns regarding its biosafety. For large programs, its collection can take several hours or days to complete. In addition, natural urine has an unpleasant smell, which tends to worsen with increasing storage time. In order to solve some of these problems, the Bioassay Section at the Radiation Protection Bureau in Health Canada has been investigating the use of tea in both PTP and ICP exercises. A method based on diluting tea steeps and scanning them in the UV-VIS range of the light spectrum to select appropriate concentrations as simulated urine for the programs has been published. So far, however, only single H and single C in tea have been studied. The results were found to be compatible and very successful under the S-106 standard of the Canadian Nuclear Safety Commission. This report is an extension of similar investigations and shows that tea samples spiked with both H and C (DUAL) are also compatible and produce excellent PTP results.

Recycling greenhouse gas fossil fuel emissions into low radiocarbon food products to reduce human genetic damage

Radiocarbon from nuclear fallout is a known health risk. However, corresponding risks from natural background radiocarbon incorporated directly into human genetic material have not been fully appreciated. Here we show that the average person will experience between 3.4 × 10¹⁰ and 3.4 × 10¹¹ lifetime chromosomal damage events from natural background radiocarbon incorporated into DNA and histones, potentially leading to cancer, birth defects, or accelerated aging. This human genetic damage can be significantly reduced using low radiocarbon foods produced by growing plants in CO₂ recycled from ordinary industrial greenhouse gas fossil fuel emissions, providing additional incentive for the carbon sequestration.

Natural background radioactive carbon and the natural death rate of people

A brief analysis of the known data on the potential danger of radiocarbon incorporation into DNA structure shows that the great genetic importance of transmutational transformations of DNA-incorporated 14C is theoretically and experimentally proved. This effect exists both in huge and small radiation doses (similar to doses of 14C natural background radiation). Therefore, the human death rate can be assumed to be dependent on natural and anthropogenous fluctuations of atmospheric 14C. Calculation methods of the age parameter dynamics of the natural human death rate are offered. It is shown that when calculating the parameters of the natural death rate, the use of Gompertz's formula is reasonable provided that the data on the general death rate are taken for the age interval "60 to 85 years." The ratios reflecting the regular and casual errors of the parameters R and a of Gompertz's equation, caused by people's casual deaths, were determined. A comparison of the historical dynamics of people's natural death rates in the last 150 years with the variations of 14C of the natural background during the same period showed that these are coordinated phenomena, the strong correlation of which indicates the possibility of their functional dependence. The 14C-concentration increase in an organism is the result of its increase in the surrounding biospheric composition, causing an increase in the natural death rate and vice versa: The increase of a person's life expectancy is caused by a decrease of 14C concentration.

Radiation exposure from long-lived beta emitters in clinical investigation

Potential hazards restrict the use of 14C in clinical investigation. Nevertheless, 14C, in readily metabolized compounds, continues to be administered and in relatively large doses. The compounds are converted to intermediates and products with longer half-lives than their half-lives. These longer biological half-lives have not always been taken into account, although calculations of radiation exposure can be markedly altered by their inclusion. The minimum dose of 14C needed to accomplish a study must also be considered, and benefits relative to risks in the administration must be assessed in terms of the kind and total number of subjects required. Similar considerations apply to the administration of 3H-labeled compounds. Furthermore, in assessing risks, the limited information available on the localization and concentration of the isotopes in the body should be taken into account. There are also concerns with regard to administrations in growth situations and to an individual on multiple occasions. Within those constraints, 14C and 3H can be given with relative safety.

Tritium Distribution in Ground Water around Large Underground Fusion Explosions

Tritium will be released in significant amounts from large underground nuclear fusion explosions in the Plowshare Program. The tritium could become highly concentrated in nearby ground waters, and could be of equal or more importance as a possible contaminant than other long-lived fission-product and induced radionuclides. Behavior of tritiated water in particular hydrologic and geologic environments, as illustrated by hypothetical explosions in dolomite and tuff, must be carefully evaluated to predict under what conditions high groundwater concentrations of tritium might occur.