Updated findings provide insights into radiation exposure’s impact on cancer risk
by University of California, Irvine, 7 Oct 24, https://medicalxpress.com/news/2024-10-insights-exposure-impact-cancer.html
A major update was made to the International Nuclear Workers Study (INWORKS), an international epidemiological study of workers in the nuclear sector to assess their risks of cancer and non-cancerous diseases.
David Richardson, Ph.D., professor of environmental and occupational health at UC Irvine Joe C. Wen School of Population & Public Health, was the principal investigator for this study and senior author of a publication in The Lancet Haematology that outlines the new findings.
With the study update, Richardson and colleagues sought to understand the associations between low-dose exposure to penetrating forms of ionizing radiation and its effect on risk of leukemia, lymphoma and multiple myeloma.
The researchers assembled a cohort of more than 300,000 radiation-monitored workers from France, the United Kingdom and the United States, employed at nuclear facilities between 1944 and 2016. Using Poisson regression methods, researchers measured the amount of radiation that got absorbed into bone marrow.
Since radiation exposure is a known risk factor for leukemia, excluding chronic lymphocytic leukemia, the study primarily focused on measuring incidence of leukemia and other cancer subtypes such as myelodysplastic syndromes, Hodgkin and non-Hodgkin lymphomas, and multiple myeloma.
The study revealed a positive association between prolonged low-dose exposure to ionizing radiation and mortality from these hematological cancers. The study concluded that health risk remains low at low exposure levels. Nevertheless, the evidence of associations between total radiation exposure and multiple myeloma and myelodysplastic syndromes signals the necessity for future radiation studies to expand the discussion on radiation protection and occupational safety measures on a global scale.
“Our studies of people exposed to low doses of radiation add to our understanding of radiation risks at the exposure levels encountered in many contemporary settings,” said Richardson who is the associate dean for research at Wen Public Health. “Our results can inform radiation protection standards and will provide input for discussions on protections from radiation.”
More information: Klervi Leuraud et al, Leukaemia, lymphoma, and multiple myeloma mortality after low-level exposure to ionising radiation in nuclear workers (INWORKS): updated findings from an international cohort study, The Lancet Haematology (2024). DOI: 10.1016/S2352-3026(24)00240-0
Journal information: The Lancet Haematology
Radon, even at levels below EPA guideline for mitigation, is linked to childhood leukemia
By ONA Editor October 6, 2024 , https://oncologynews.com.au/latest-news/radon-even-at-levels-below-epa-guideline-for-mitigation-is-linked-to-childhood-leukemia/?fbclid=IwY2xjawFvCqBleHRuA2FlbQIxMQABHS5488aZnUZ2hNIA841-HCIezMi-9ZMQB1QfxQQZpYE67Zfdt00GeqwWew_aem_ccu2uE8COyQskZQX6eY3Bw
A study of more than 700 counties across multiple U.S. states found a link between childhood leukaemia and levels of decaying radon gas, including those lower than the federal guideline for mitigation.
The findings are important because there are few established risk factors for cancer in children and the role of the environment has not been explored much, said Oregon State University’s Matthew Bozigar, who led the research.
Radon, a naturally occurring gas, is a product of the radioactive decay of uranium, which is present in certain rocks and soils.
Upon escaping from the ground, radon itself decays and emits radioactive particles that can get within the body and collect in many tissues, where they can damage or destroy the cells’ DNA, which can cause cancer.
Odourless, tasteless and colourless, radon gas dilutes quickly in open air and is generally harmless before it decays, but indoors or in areas with poor air exchange, it can easily concentrate to dangerous levels and is recognised as a significant risk factor for lung cancer.
Radon, measured with small, passive detectors and mitigated through passive or active ventilation in basements and crawl spaces, has not been linked to other cancers, according to the World Health Organisation.
But in an 18-year statistical modelling study of 727 counties spread among 14 states, Bozigar and collaborators not only found a connection between childhood leukaemia and radon, but at concentrations below the Environmental Protection Agency’s recommended guideline for mitigation.
Becquerels per cubic metre is a unit for expressing the concentration of radioactive decay in a given volume of air.
The EPA says no level of radon is safe and advises that mitigation efforts be taken when radon concentration reaches 148 becquerels per cubic metre; the study considered concentrations as low as half of that.
“This is the largest study of its kind in the U.S., but more robust research is necessary to confirm these findings on an individual level and inform decision-making about health risks from radon in this country and globally,” said Bozigar, an assistant professor in the OSU College of Health.
Leukaemia, the most common cancer in children, affects the blood and bone marrow.
About 3,000 new cases of childhood leukaemia – defined in the study and by the National Institutes of Health as involving patients up to age 19 – are diagnosed in the United States each year, according to the NIH.
The annual incidence rate is 4.8 cases per 100,000 children.
Boys are more likely to receive a leukaemia diagnosis than girls, but the research suggests radon increases the likelihood of leukaemia in both sexes.
“Our study design only allows us to identify statistical associations and to raise hypotheses, so studies that can better determine whether radon exposure causes childhood leukaemia are needed,” Bozigar said.
Counties examined in this study were in the states of Washington, California, Idaho, Utah, New Mexico Iowa, Louisiana, Kentucky, Michigan, Georgia, New York, New Jersey, Connecticut and Massachusetts.
The counties are those that during the study period reported their cancer data to the Surveillance, Epidemiology and End Results registry, a programme that collects and analyses cancer information.
Known as SEER, the registry is supported by the National Cancer Institute.
Collaborating with Bozigar were scientists from the National Cancer Institute, Harvard University and Imperial College London.
The research, funded in part by the Environmental Protection Agency, was published in Science of the Total Environment.
For Bozigar, the research has its roots in personal experience.
He grew up in Portland, which has pockets of high radon levels, and noticed what seemed to be a high incidence of cancer, particularly in younger age groups.
There were multiple cancer diagnoses among his own family and friends.
“As an epidemiologist, I started considering possible environmental causes and connected with awesome collaborators who provided important data and other resources to enable innovative new analyses,” he said.
“We are working on many different radon studies, and we are continuing to find harmful effects not limited to the lungs in adults. We will have more to share in the coming months and years as our studies are published.”
Source: Oregon State University
The challenge of long-lived alpha emitters in the Chalk River legacy wastes
Concerned Citizens of Renfrew County and Area, January 22, 2024 (revised September 17, 2024)
Why is so little Chalk River waste suitable for near surface disposal?
Extensive research work at the Chalk River Laboratories on nuclear reactor fuels, and in the early days, on materials for nuclear weapons, produced waste with large quantities of long-lived alpha emitters. This waste is difficult to manage and can even become increasingly radioactive over time.
According to the International Atomic Energy Agency, because of the presence of long-lived alpha emitters, waste from nuclear research facilities is generally classified as intermediate level, and even in some cases, as high level. This waste cannot be put in a near surface disposal facility because its radioactivity will not decay to harmless levels during the period that the facility remains under institutional control.
Alpha emitters decay by throwing off an alpha particle, the equivalent of a helium nucleus, with two protons and two neutrons. The external penetrating power of an alpha particle is low, but alpha emitters have extremely serious health effects if ingested or inhaled. They can lodge in your lungs and cause cancer.
Research at Chalk River and all other nuclear laboratories is ultimately based on three long-lived alpha emitters — thorium-232, uranium-235, and uranium-238. These are the “naturally occurring” or “primordial” radionuclides. They were created by large stars and then incorporated into the Earth and the solar system when they formed some 4.5 billion years ago. The waste inventory proposed by Canadian Nuclear Laboratories for the Near Surface Disposal Facility (NSDF) includes over six tons each of thorium-232 and uranium-238……………………………………………………..
Hazards increase when uranium and thorium are mined and concentrated from ores and used in their pure form. Marie Curie, who spent much of her career isolating radium and polonium from uranium, died of radiation-induced leukemia at age 66. She was buried in a lead-lined tomb because her corpse emitted so much radiation.
When thorium-232, uranium-235, and uranium-238 are irradiated in a reactor, as at Chalk River, they absorb neutrons and produce significant quantities of new, man-made, long-lived alpha-emitters. Irradiated uranium-238 absorbs a neutron and temporarily forms uranium-239. Uranium-239 transmutes to neptunium-239, which quickly transmutes to long-lived plutonium-239, with a half-life of 24,000 years.
Plutonium-239 is “fissile” – it can readily support a chain reaction. It is what the early Chalk River researchers produced for the manufacture of U.S. nuclear weapons, by separating the plutonium from irradiated reactor fuel. They also used the separated plutonium to make “mixed oxide” (MOX) reactor fuel, mixing it with fresh uranium………………………………………….
Detecting alpha emitters in mixed waste is expensive and challenging. Putting inadequately characterized waste in the NSDF would invalidate its safety case.
Unfortunately, the NSDF Project lacks adequate waste characterization procedures. If the project is allowed to proceed, workers and future Ottawa valley residents could be exposed to unknown quantities of long-lived alpha emitters and suffer the serious health effects associated with them. https://concernedcitizens.net/2024/09/17/the-challenge-of-long-lived-alpha-emitters-in-the-chalk-river-legacy-wastes/
Radiation levels mysteriously spike along Norway’s border with Russia – as it’s claimed activity has been seen at test site for Putin’s ‘Flying Chernobyl’ nuclear missile
Traces of radioactive Cesium-137 have been
measured along Norway’s border with Russia, it was revealed today. The
radiation levels are ‘clearly’ higher than normal, authorities have said,
and the cause of the mysterious spike is unknown.
One fear is that it could
relate to Russia’s Pankovo test site for the Burevestnik – a
nuclear-powered, nuclear-armed cruise missile – on the Novaya Zemlya
archipelago.
Daily Mail 17th Sept 2024
Tritium into the air?
“You get layers and layers and layers and layers of denial.”
Venting plans at Los Alamos have received scant attention, writes Alicia Inez Guzmán of Searchlight New Mexico
Beyond Nuclear International, 16 Sept 24
Last fall, the international community rose up in defense of the Pacific Ocean. Seafood and salt purveyors, public policy professors, scientists and environmentalists, all lambasted Japan’s release of radioactive wastewater from the disastrously damaged Fukushima Daiichi nuclear plant into the sea.
At the heart of the contention was tritium, an element that, by mass, is 150,000 times more radioactive than the plutonium used in the cores of nuclear weapons. Odorless and colorless, tritium — the radioactive form of hydrogen — combines with oxygen to form water. Just one teaspoon is enough to contaminate 100 billion gallons more water up to the U.S. drinking water standard, according to Arjun Makhijani, an expert on nuclear fusion and author of the monograph, “Exploring Tritium Dangers.”
What didn’t make international headlines — but was quietly taking place on the other side of the world — was Los Alamos National Laboratory’s own plans to vent the same radioactive substance into northern New Mexico’s mountain air. Japan’s releases would take place over three decades. LANL’s would include up to three times more tritium — and take place in a matter of days.
There is no hard timeline for the release, but if the plans are approved by the Environmental Protection Agency, LANL is looking at a period with “sufficiently warm weather,” a spokesperson from the National Nuclear Security Administration wrote by email. That could mean as soon as this summer.
Those controversial plans date back to 2016, when LANL discovered that a potentially explosive amount of hydrogen and oxygen was building up in four containers of tritium waste stored in a decades-old nuclear dump called Area G. The safest and most technically viable solution, the lab decided — and the best way to protect workers — would be to release the pressure and, with it, thousands of curies of tritium into the air.
When advocates caught wind of the venting in March 2020, Covid was in its earliest and most unnerving phase. Pueblo leaders, advocates and environmentalists wrote impassioned letters to the lab and the EPA, demanding that they change or, at the very least, postpone the release until after the pandemic. At the same time, Tewa Women United, a nonprofit founded by Indigenous women from northern New Mexico, issued its first online petition, focusing on tritium’s ability to cross the placental barrier and possibly harm pregnant women and their fetuses. Only after a maelstrom of opposition did the lab pause its plans and begin briefing local tribes and other concerned members of the community.
“We see this as a generational health issue,” said Kayleigh Warren, Tewa Women United’s food and seed sovereignty coordinator. “Just like all the issues of radioactive exposure are generational health issues.”
Last fall, the lab again sought the EPA’s consent. A second petition from Tewa Women United followed. Eight months later, the federal agency’s decision is still pending.
The NNSA, which oversees the health of America’s nuclear weapons stockpile from within the Department of Energy, declined Searchlight New Mexico’s requests for an interview.
The crux of the issue comes down to what is and isn’t known about the state of the containers’ contents. Computer modeling suggests they are pressurized and flammable, but the actual explosive risk has not been measured, the lab has conceded.
Critics have requested that the contents be sampled first to determine whether there is any explosive risk and whether venting is even needed. The EPA says that sampling would require going through the same red tape as venting. The lab, for its part, plans to sample and vent the contents in one fell swoop.
But why, critics wonder, are these containers in this state in the first place? Were they knowingly over packed and left for years to grow into ticking time bombs?…………………………………………………………………………………………………………………………………..
……………..Tritium 101
Plutonium and uranium are familiar to most people, if by name only. But few know anything at all about tritium — a radioactive isotope of hydrogen that is used to make watch dials and EXIT signs glow bright neon. Tritium’s other, lesser-known use is as a “boost gas,” which, when inserted into the hollow core of a plutonium pit, amplifies a nuclear weapon’s yield. Globally, hundreds of atmospheric weapons tests dispersed tritium into the atmosphere, steeping rain, sea, and groundwater with the element and, ultimately, lacing sediment worldwide.
Tritium is widely produced at nuclear reactors and is today tested, handled and routinely released at Los Alamos National Laboratory
Criticisms of this venting have always centered on two of the element’s key characteristics: First, it travels “tens to hundreds of miles,” according to lab documents. Second, when tritium is in the form of water, it becomes omnipresent and easy for bodies to absorb.
“Tritium is unique in this,” wrote Makhijani. “It makes water, the stuff of life, most of the mass of living beings, radioactive.”
Years of LANL reports depict tritium’s ubiquity in the lands and ecosystem within its bounds, a palimpsest of radioactive decay. This is measured in curies, a basic unit that counts the rate of decay second by second.
The lab’s first environmental impact statement, published in 1979, estimated that it had buried close to 262,000 curies of tritium at Area G and released tens of thousands more into the air from various stacks over the decades. The lab had two major accidental releases of tritium around the same time — 22,000 curies in the summer of 1976 and nearly 31,000 curies in the fall of 1977.
Today, trees have taken it into their root systems on Area G’s southeast edge. Rodents scurrying in and out of waste shafts are riddled with the substance, owing to tritium vapors from years past. A barn owl ate those rodents and had 740 times more tritium concentration in its body than the U.S. drinking water standard, the common reference value for indicating tritium contamination. The lab’s honeybee colonies — kept to determine how radioactive contaminants are absorbed — produced tritiated honey up to 380 times more concentrated than the drinking water standard, reports show.
The EPA set the current standard for radioactive emissions at DOE facilities in 1989, but that didn’t stop the lab from releasing thousands of curies of tritium into the air shortly afterward. In 1991, the EPA issued a notice of non-compliance to the lab for not calculating how much of a radiation dose the public received. Another notice followed in 1992.
Concerned Citizens for Nuclear Safety filed a lawsuit two years later alleging that the DOE hadn’t properly monitored radioactive emissions, as required by the Clean Air Act. At the time, a former lab safety officer, Luke Bartlein, observed what he described in an affidavit as a “pattern and practice of deception at LANL with respect to the radionuclide air monitoring system.” It was routine for lab staffers and management to vent glove boxes and other materials contaminated with tritium outside so that the contamination would deliberately “not register” on the stack monitors, he recounted, leading to false emissions reports.
The lab settled in 1997; a consent decree followed and would stay in effect until 2003. The lab says it has maintained low annual emissions ever since……………………………………………………………………………………………………………..
Tewa Women United and others now worry that the region’s famously fitful winds will carry tritium, a consummate shapeshifter, to corners far beyond the lab’s bounds.
The movement will be invisible. First, tritium will transform moisture in the air. Then, that moisture will quickly contaminate other “open water surfaces and biota downwind, including food growing in the area and food in open-air markets, and humans themselves,” according to Ian Fairlie, a London-based radiation consultant for the European Parliament.
A fraction of that tritium can linger in the body, if ingested. In pregnant women, tritium can then stage another imperceptible passage across the placental barrier, concentrating 60 percent more of the element in the fetus than in the mother, according to Makhijani. Radiation exposure can lead to early failed pregnancies and neurological damage in the first weeks of gestation.
While the Nuclear Regulatory Commission has radiation exposure limits for pregnant women in the workplace, there are no specific radiation protections for pregnant women in the public — or their fetuses.
In 1999, Makhijani and more than 100 scientists, activists and physicians across the country and worldwide signed a letter to the National Academy of Sciences. Their ask? To evaluate how radionuclides that cross the placental boundary, including tritium, impact the fetus, a request Makhijani renewed in 2022.
As he put it, tritium — the “most ubiquitous pollutant from both nuclear power and nuclear weapons” — has largely escaped regulatory and scientific scrutiny when it comes to matters of pregnancy.
Cindy Folkers, the radiation and health hazard specialist at Beyond Nuclear, a national advocacy organization, believes the reason is rooted in the radiation establishment’s fear of liability. “You get layers and layers and layers and layers of denial.”
The scant research that does exist comes from pregnant women who survived atomic bombs in Hiroshima and Nagasaki. In 1986, the International Commission on Radiation Protection concluded that exposing a fetus to ionizing radiation, the kind that tritium emits, has a “damaging effect…upon the development of the embryonic and fetal brain.” The area most at risk of harm, it went on, is the forebrain, which controls complex and fundamental functions like thinking and processing information, eating, sleeping and reproduction.
Ionizing radiation damages the cell in two ways. On the one hand, it breaks apart the building blocks from which humans are made, causing rifts in DNA. On the other, it fundamentally changes the chemistry of the cell, breaking apart its water molecules and upsetting its metabolism.
That’s what makes it different from, say, an X-ray, Folkers said. “A machine can be shut off,” but “a radioactive particle that’s inside your body will continue irradiating you.” For a pregnant woman, this adds up to “cumulative biological damage,” the kind that cuts across generations.
“We’re dealing with a life cycle,” Folkers said. “And females are an integral part of that life cycle. Not only are they more damaged by radioactivity, and their risks are higher for cancer, but they are also carrying in them the future generations. So when you’re dealing with a female baby who’s developing in the womb, you are dealing with that child’s children at the very least.”
In other words, a mother is like a Russian nesting doll. She holds a fetus and that fetus, if a female, holds all future eggs. Exposure to her is exposure to future generations.
Alicia Inez Guzmán was raised in the northern New Mexican village of Truchas and has written about histories of place, identity and land use in New Mexico. She brings this knowledge to her current role at Searchlight, where she focuses on nuclear issues and the impacts of the nuclear industry. https://beyondnuclearinternational.org/2024/09/16/tritium-into-the-air/
Christopher Busby: New study: the cause of the cancer epidemic
15 Sept 2024, https://www.youtube.com/watch?v=kMauRgvWnII
Dr Busby presents the results of a study which he carried out to identify the cause of the cancer epidemic which began in 1980. He compared cancer death rates between high fallout and low fallout States in the USA looking for an effect which identified the period of birth of the ten year age groups.
The result showed an astonishing cancer risk effect centred around the peak years of atmospheric test fallout, 1955 to 1965. The result showed a 50% excess risk of dying of cancer in the 55-64 year olds who were born during the fallout years. A earlier version of the study, whic he carried out in 2021 was presented in the journal BMJ Oncology in 2023 and can be found online. Link is https://bmjoncology.bmj.com/content/e…
What this means, he explains, is that it is likely that there is a significant probability that you, or anyone you know who has developed cancer, is a victim of the atmospheric test fallout contamination of Strontium-90 and Uranium-238. The total number of victims of this exceeds 100 million.
He says that those who have been anticipating World War should realise that it has already happened. It was the war of the nuclear military complex against humanity, as Dr John Gofman once said. Further videos in this series Science and reality will take this matter further. He belatedly apologises for placing the high fallout States in the west; they are of course in the south east of USA
COMMENT. Very important. In Australia, through the1960s and even later, repeated bursts of atmospheric fallout from the French nuclear tests . Rainfall from the East was tested for radiation – but the results were kept secret. Prof Ernest Titterton was in charge, and he cancelled the tests anyway. Interesting to study the cancer rates of East coast populations exposed at that time.
The scientific nature of the linear no-threshold (LNT) model used in the system of radiological protection
the LNT concept can be tested in principle and fulfils the criteria of a scientific hypothesis. The fact that the system of radiological protection is also based on ethics does not render it unscientific either
attempts to discredit the LNT approach as being non-scientific lack any sound basis, and are in fact counterproductive with respect to the aims of radiological protection, because they preclude any constructive debate.
Radiation and Environmental Biophysics , 02 September 2024, Andrzej Wojcik & Friedo Zölzer https://link.springer.com/article/10.1007/s00411-024-01092-1—
During the first half of the 20th century, it was commonly assumed that radiation-induced health effects occur only when the dose exceeds a certain threshold. This idea was discarded for stochastic effects when more knowledge was gained about the mechanisms of radiation-induced cancer.
Currently, a key tenet of the international system of radiological protection is the linear no-threshold (LNT) model where the risk of radiation-induced cancer is believed to be directly proportional to the dose received, even at dose levels where the effects cannot be proven directly.
The validity of the LNT approach has been questioned on the basis of a claim that only conclusions that can be verified experimentally or epidemiologically are scientific and LNT should, thus, be discarded because the system of radiological protection must be based on solid science.
The aim of this publication is to demonstrate that the LNT concept can be tested in principle and fulfils the criteria of a scientific hypothesis. The fact that the system of radiological protection is also based on ethics does not render it unscientific either. One of the fundamental ethical concepts underlying the LNT model is the precautionary principle
We explain why it is the best approach, based on science and ethics (as well as practical experience), in situations of prevailing uncertainty.
Introduction
A basic assumption of the international system of radiological protection, as recommended by the International Commission on Radiological Protection (ICRP), is that the risk of radiation-induced cancer is directly proportional to the dose received, without any dose level (threshold) below which the risk is zero (ICRP_99 2005). This so-called linear no-threshold (LNT) model is strongly criticized by, on the one hand, researchers claiming that it underestimates the actual risk, because it does not consider, among other possible modifying factors, bystander effects according to which the relationship is more properly described by a supralinear curve (Mothersill and Seymour 2004).
On the other hand, some researchers claim that adaptation processes reduce the radiation-related risk at low doses, resulting in a threshold dose below which there is either no effect or even health benefit (hormesis) (Sacks et al. 2016; Janiak and Waligorski 2023).
Yet others claim that both mechanistic evidence coming from radiobiology and observational evidence coming from epidemiology suggest that a dose threshold, if any, could not be greater than a few tens of mGy and, thus, the LNT model has a solid basis in results from experimental studies (Laurier et al. 2023). Also, UNSCEAR in a review of biological data, concluded that there remains good justification for the use of a non-threshold model for risk inference given the robust knowledge on the role of mutation and chromosomal aberrations in carcinogenesis (UNSCEAR 2021).
Why is it not possible to reach a consensus regarding the shape of the dose response? At low radiation doses, defined as below 0.1 Gy (UNSCEAR 2012), biological effects are very weak so they are easily influenced by random environmental factors making results difficult to reproduce. A good example are the variable results of adaptive response experiments (Wojcik and Streffer 1994; Wojcik et al. 1996; Wojcik and Shadley 2000). In general, despite new, suggestive epidemiological data (Laurier et al. 2023), mechanistic, experimental approaches with both cell and animal models are unable to provide unequivocal evidence for the existence of a dose threshold below which radiation carries no risk to human health. There is still insufficient knowledge about the sequence of events from the deleterious alteration of biomolecules to the diagnosable disease, i.e. to stochastic cancer or non-cancer effects (UNSCEAR 2021). Also, epidemiological studies mostly lack the necessary statistical power to detect effects at doses below 0.1 Gy (Ruhm et al. 2022).
Disagreement about the interpretation of results is an essential element of science and many famous scientific discoveries were accompanied by controversy and disputes (Sarewitz 2011). Consequently, it is desirable that the debate around LNT continues. However, its validity has been questioned on the basis that it is not a scientific concept and should thus be discarded because the system of radiological protection must be based on solid science (Waltar et al. 2023).
This line of argumentation precludes any constructive debate: no researcher will waste time on a non-scientific concept. More importantly, it is flawed because the system of radiological protection, as designed by the ICRP, is “based on scientific knowledge, ethical values, and more than a century of practical experience” (ICRP_138 2018). It relies wholly on state-of-the art science, understood broadly as knowledge (as distinguished from ignorance or misunderstanding), and the LNT model, being an element of the system, is a scientific concept. The aim of this publication is to demonstrate this.
LNT as a scientific concept
The authors of the recent LNT critique (Waltar et al. 2023) write that LNT lacks a solid scientific base because there are no “actually proven radiation effects at low-doses”. The risk of cancer induced by high doses of radiation, they argue, can be derived from frequentist probabilities which “are based on evidence; namely, on the truthful and verifiable existence of an increase in the frequency of radiation health effects in a cohort of exposed people and are defined as the limit of the relative frequency of incidence of the effect in a series of certifiable epidemiological studies on such cohorts”. In contrast, the risk of cancer in the low dose region is assessed based on “subjective probabilities (sometimes also confusedly termed “Bayesian”), which are conjectured for the low-dose area, expressed as a possible expectation that radiation health effects might occur, and are quantified by a personal belief or expert’s judgement; that is, not necessarily substantiated by the frequency or propensity that the effects actually occur at such levels of dose”. In short: the assumption of no threshold dose for the risk of cancer is not scientific because it cannot be proven.
The claim that whatever cannot be proven in experimental or epidemiological studies is not scientific may be based on a particular reading of Karl Popper´s “critical rationalism”, which suggests a method to distinguish between science and non-science. But if the authors had that approach in mind, their reading of it is wrong: lack of proof does not, in Popper’s view, make a hypothesis unscientific. On the contrary, Popper maintains that nothing whatsoever can really be proven; there are no verifiable truths. What scientists can do is to test a given hypothesis over and over again. If they find satisfactory evidence against it, the hypothesis is “falsified”.
If they do not find evidence against it, it is “corroborated”. The more “corroboration” we have, the more certain we can be of that particular hypothesis, but we can still not consider it “verified”. So, the criterion of “scientific” vs. “unscientific” is not “verifiability”, but “falsifiability” (Popper 1961). Popper´s method has been severely criticized for reasons that will not be discussed here. The interested reader is referred to relevant publications (Maxwell 1972; Feyerabend 2010). Despite this ongoing discussion in science theory, however, there is no doubt that the lack of positive proof for a certain model does not render it unscientific. This is true for the LNT model as well. It can, in principle, be tested. For instance, recent epidemiological studies with large numbers of people undergoing medical radiology did not show any indication of a threshold for cancer induction by radiation (Laurier et al. 2023). The latest addition to this growing body of evidence is the EPI-CT study, in which almost a million children who had to undergo a CT examination were followed for several years and their risk of hematological malignancies was quantified. A significant increase was found in the dose group of 10–15 mGy (Bosch de Basea Gomez et al. 2023). With even larger numbers, and more precise and consistent methods of dosimetry as well as diagnosis of disease, it will be possible to corroborate the LNT model even more convincingly. Of course, this will always apply to particular dose ranges and particular effects, but with those caveats in mind, the model can certainly be considered “falsifiable” and, therefore, scientific. To summarize: epidemiological studies have, until now, not been able to falsify LNT (Laurier et al. 2023). Let us have a look at attempts to falsify LNT by other approaches.
Conclusions from UNSCEAR reports on the shape of the dose response for cancer and derivation of dose limits by the ICRP
In developing its recommendations, the ICRP relies on results from the field of natural science on mechanisms and levels of health effects induced by ionising radiation. These are regularly summarised by UNSCEAR (www.unscear.org). As stated above, the epidemiological evidence on the shape of the dose response curve in the dose range relevant for planned exposure scenarios of people does not falsify LNT, but does not allow drawing firm conclusions due to lack of statistical power.
Since 1994, UNSCEAR has published four reports that look into biological effects induced by low dose exposure, with the aim of examining whether they support the assumption of the LNT concept. The 1994 report focused on adaptive responses in cells, experimental animals and humans and concludes that evidence does not exist to support the assumption that adaptive responses convey beneficial effects to the organism that would outweigh the detrimental effects of exposure to radiation (UNSCEAR 1994).
The 2000 report did not specifically focus on adaptive responses but aimed at providing an overview of data available on the relationship between radiation exposure and the induction of cancer and hereditary disease (UNSCEAR 2000). It concludes that, although mechanistic uncertainty remains, studies on DNA repair and cellular/molecular processes of radiation tumorigenesis provide no good reason to assume that there will be a low-dose threshold for the induction of tumours in general.
In support of this, the authors of the report discuss DNA double strand breaks (DSB) originating from single ionizing tracks of radiation that occur in the low dose range. Although their incidence is low, they may arise from the more likely single strand lesions, when these occur in close proximity on opposed DNA strands. Furthermore, the report points out that single ionization tracks were shown to induce locally multiply damaged sites (LMDS). LMDS pose a particular problem for the cellular DNA repair system and will most likely be misrepaired, leading to a mutation and potentially – cancer. This evidence is important in view of existing opinions that low doses of radiation merely increase the level of the naturally occurring oxidative damage that has no negative consequences because cells are well equipped to cope with it (Tubiana 2005). Of course, oxidative damage does occur naturally and appropriate repair processes exist, but its spatial distribution is different from that caused by the ionisation tracks of photons and particles in the form of locally multiply damaged sites.
The aim of the next report, published in 2006, was “to evaluate how non-targeted effects may affect risks associated with radiation exposure, the understanding of radiation-induced carcinogenesis, and the mechanistic basis for interpreting epidemiological data on radiation effects” (UNSCEAR 2006). The report concludes that data currently available do not require changes in radiation risk coefficients for cancer and hereditary effects of radiation in humans.
The last report was published in 2021 (UNSCEAR 2021). Its focus is on biological mechanisms of radiation actions at doses mostly in the low to moderate range relevant for cancer risk inference. Consequently, it looks at available knowledge on DNA damage and repair, chromatin remodelling and epigenetics, gene and protein expression, non-targeted effects, the immune system and modelling of cancer mechanisms. In accordance with the previous reports, it concludes that accumulated knowledge on mechanisms of effects directly related to cancer induction imply a dose-risk relationship without a threshold at least down to 10 mGy and that “little in the way of robust data could be identified that would prompt the need to change the current approach taken for low-dose radiation cancer risk inference as used for radiation protection purposes and for the purpose of comparison with other risks”. In summary, neither epidemiological nor mechanistic studies provide unequivocal evidence for the shape of the dose-response curve, although they confirm that the LNT concept is falsifiable in principle – at least for certain dose ranges.
The ethical basis of radiological protection as a scientific concept
If it is not possible to quantify the risk of stochastic effects at low doses, how did the ICRP arrive at the dose limits that are currently recommended? A historical reconstruction of the considerations underlying the setting of dose limits was recently published by one of us (Zolzer 2022). Here, as well as elsewhere in radiological protection, assumptions about risks at small doses need to be made. If recommendations for radiological protection would have to be based on scientific evidence alone, one might point to the (undeniable and undenied) uncertainties about the LNT concept and remain doubtful as to its applicability. As stated above, however, the ICRP’s system is “based on scientific knowledge, ethical values, and more than a century of practical experience” (ICRP_138 2018). Usually, of course, ethics and practice per se are not considered scientific (which in itself is open to debate), but it needs to be emphasised that the role which they play for the system of radiological protection does not render that system unscientific.
“Ethics” can mean different things. It can denote a set of beliefs and values regarding what is right and what is wrong, and as such can be used in combinations like “the ethics of a particular individual”, “the ethics of a particular group”, or “the ethics of a particular society, culture, or religion“. The same word, however, can also designate a branch of philosophy, sometimes called “moral philosophy”, which systematically studies this kind of beliefs and values. “Ethics” in this sense is clearly a rational endeavour. It examines standards of rightness and wrongness, and their application to practical problems, but it does not single out a concrete standard, i.e. it does not become prescriptive.
What is right and what is wrong can only be established within the context of a particular ethical system. Utilitarian ethics, for instance, recognizes as the criterion of right and wrong nothing but the “greatest happiness of the greatest number” (Bentham 1776), whereas in deontological ethics everything depends on “treating humanity, whether in your own person or that of another, never merely as a means to an end” (Kant 1785). There are other systems, of course. Virtue ethics, for instance, has recently received renewed interest (Aristotle being an early proponent). It is concerned not so much with actions and their consequences, but with people’s characters and dispositions. Consistent ethical judgement is possible on the basis of either of these theories, but they do not always lead to the same result. Thus, there is no such thing as an ethics which is universally applicable and binding for all.
Coming back to radiological protection, it may be interesting to note that around the turn of the 21st century several authors, among them members of ICRP, argued that the three principles of radiological protection – justification, optimization, and dose limitation – are based on one or the other classical theory of Western moral philosophy as outlined above. The ICRP itself in its first publication fully dedicated to the topic of ethics (ICRP_138 2018) has discussed this kind of arguments in an appendix to that publication. In the main body of the report, however, they took a different approach. Recognizing that radiological protection is a world-wide endeavour, it was decided to take as a point of departure a certain set of moral values which are common (or at least acceptable) to people from different cultural backgrounds. These values did not have to be invented from scratch but had been referred to implicitly or explicitly in earlier publications of the IRCP.
The approach is similar to an ethical theory suggested in 1979 by Beauchamp and Childress and widely applied in medicine, called the “principles of biomedical ethics” (Beauchamp 1979). The authors originally worked on quite different basic assumptions, one being a utilitarian, the other a deontological ethicist, but they realised that in spite of belonging to different schools of thought, they could still agree on a number of “principles” which allowed them to solve most ethical dilemmas in clinical practice. They identified these principles as Respect of autonomy, Non-maleficence, Beneficence, and Justice. All of them, they maintained, had prima facie validity, i.e. all of them seem applicable at first sight without any particular ranking, but in certain clinical situations not all of them can be applied in the same way, one or the other having to take precedence. This they called “balancing the principles” and they discussed many examples of how to determine the relative importance of each principle in particular situations.
What the ICRP proposed in Publication 138 is very similar, but it does not copy the Beauchamp and Childress approach one-to-one. The fundamental concepts are called “values” instead of “principles”, because that term is already used for justification, optimization and dose limitation, and more importantly, the four “core values” are slightly different: Beneficence/Non-maleficence, Prudence, Justice, and Dignity. Their application in different contexts, as well as the necessity to “balance” them against each other, is discussed in Publication 138, as well as Publication 153 on “Radiological Protection in Veterinary Practice” and in the up-coming publication on “Ethics in Radiological Protection for Medical Diagnosis and Treatment”. We will not go into any detail here, but just state again that the ethics of radiological protection, as practiced by the ICRP, is not a promotion of subjective convictions or preferences, or a reflection of “personal beliefs”, but is well in line with current trends in moral philosophy.
Prudence is not part of the Beauchamp and Childress set of principles, or values, but does play an important role for radiological protection. The ICRP itself has pointed this out. The 1956/57 amendment to the 1954 recommendation (ICRP_1958, 1958) already stated that ‘it is prudent to limit the dose of radiation received by gametes (…) to an amount of the order of the natural background’, and a similar statement appeared in Publication 1 (ICRP_1 1959), where prudence again played an important role in the justification of dose limits. The ICRP recognised that its recommendations could no longer be based on well-documented tissue reactions, but had to take account of stochastic effects for which there was no more than a certain plausibility. And even though the risks were hard to quantify for the time being, one had to make an attempt to weigh them against the expected benefits of activities involving radiation exposure. This is why ICRP recommended early on ‘that every effort be made to reduce exposure (…) to the lowest possible level’ (ICRP_1955, 1955), ‘that all doses be kept as low as practicable’ (ICRP_1 1959), or ‘that all doses be as low as readily achievable, economic and social consequences being taken into account’ (ICRP_9 1966). All three formulation are obviously early formulations of the ALARA principle, “doses should all be kept as low as reasonably achievable, taking into account economic and societal factors” (ICRP_103 2007). ICRP also suggested that dose limitation ‘necessarily involves a compromise between deleterious effects and social benefits’ (1959) (ICRP_1 1959) and that one has to find ‘a level at which the assumed risk is deemed to be acceptable to the individual and to society in view of the benefits derived from such activities’ (ICRP_9 1966).
In the latest general recommendations (ICRP_103 2007), the ICRP states that “it is prudent to take uncertainties (…) into account”, even when it comes to the estimates of threshold doses for deterministic effects. More importantly, the “so-called linear-non-threshold (LNT) model is considered by the Commission to be the best practical approach to managing risk from radiation exposure… The Commission considers that the LNT model remains a prudent basis for radiological protection at low doses and low dose rates.” Furthermore, in spite of lacking evidence in humans for radiation effects on offspring and next generations, “the Commission prudently continues to include the risk of heritable effects in its system of radiological protection” and “considers that it is prudent to assume that life-time cancer risk following in-utero exposure will be similar to that following irradiation in early childhood, i.e., at most, about three times that of the population as a whole.” In Appendix A, the stress is again on practicality: “The LNT model is not universally accepted as biological truth, but rather, because we do not actually know what level of risk is associated with very-low-dose exposure, it is considered to be a prudent judgement for public policy aimed at avoiding unnecessary risk from exposure.”
In one of the passages just quoted, the ICRP mentions that its emphasis on prudence is “commensurate with the ‘precautionary principle’ (UNESCO 2005)” (for further information on the principle, see (Martuzzi and Bertollini 2004; Tallacchini 2005). This has raised red flags for some, who tend to think that radiological protection is overdone anyway and actually “crippling the beneficial effects that controlled radiation offers to a modern society” (Waltar et al. 2023). It cannot be emphasized enough, however, that the precautionary principle is often (willingly or unwillingly) misinterpreted. It does not say that with the slightest suspicion of a risk, however small it may be, all related activities should be stopped. It does not, as some have put it, provide blanket authorization for technophobia. One of the most widely used versions of the principle states: “When an activity raises threats of harm to human health or the environment, precautionary measures should be taken even if some cause and effect relationships are not fully established scientifically.” This is the so-called ”Wingspread Statement”, issued in 1998 by a diverse group of scientists, philosophers, lawyers and environmental activists from the United States, Canada and Europe. . The wording is similar to that of the “Rio Declaration” six years earlier, which says, “Where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation.”
Note that the “Rio Declaration” calls for “cost-effective measures”, which suggests a similar weighing of risks and benefits as the recommendation to keep doses “as low as reasonably achievable, taking into account economic and societal factors” (see above). Admittedly, not every version of the ‘precautionary principle’ contains this qualification. Quite often, the emphasis is very much on avoiding risks. This is perhaps the main reason why the ICRP preferred prudence as a core value: it contains the notion of a careful consideration of both, the negative as well as the positive consequences of an action or practice. In a way, it is precaution combined with solidarity, if by the latter we understand (for want of a better term) “taking into account economic and societal consequences”.
As this brief discussion also indicates, the precautionary principle is not beyond criticism, and may need further explication (Hansson 2020). That does not mean, however, that its substance would be controversial. In our context it may mean this: those in charge of setting the rules of radiological protection cannot excuse themselves on the grounds of uncertainties in our scientific knowledge; they have to act upon plausible indications of risks, while not losing sight of the reasonability of their actions, taking into account economic and societal factors. This requires critical evaluation of the existing evidence, as well as exercising their responsibilities in terms of the “core values” mentioned above. The ICRP itself (ICRP_138 2018) has put it as follows: “Neither prudence nor the precautionary principle should be interpreted as demanding zero risk, choosing the least risky option, or requiring action just for the sake of action. The experience of over half a century of radiological risk management applying the optimisation principle can be considered as a reasoned and pragmatic application of prudence and/or the precautionary principle”. It is not impossible, of course, that at some point a revision of the system of radiological protection will become necessary, perhaps even a reassessment of the LNT model, but that must be left to rational analysis and discussion and cannot be pushed through by sowing doubts regarding the scientific anchoring of radiological protection as it is practised now.
Conclusions
There is no doubt that, in order to be accepted by stakeholders and society at large, the system of radiological protection must be based on solid science. A common misconception, however, is that only conclusions that can be positively “proven” experimentally or epidemiologically are “scientific”. Notably, the assumption of direct proportionality with radiation dose for certain health effects (the linear no-threshold model) has been called unscientific because results describing effects after very low doses are inconclusive.
Here we argue that it is not positive “proof” which renders a hypothesis “scientific”, but its fundamental “testability”. Currently, direct evidence in support of the LNT model is available down to a few tens of mSv. Testing it at even smaller doses seems possible in principle, but such studies are not available yet and must be left for the future. In situations like this, ethical considerations take on special importance – which does not render the whole system unscientific either.
Here we argue that it is not positive “proof” which renders a hypothesis “scientific”, but its fundamental “testability”. Currently, direct evidence in support of the LNT model is available down to a few tens of mSv. Testing it at even smaller doses seems possible in principle, but such studies are not available yet and must be left for the future. In situations like this, ethical considerations take on special importance – which does not render the whole system unscientific either.
Leukaemia, lymphoma, and multiple myeloma mortality after low-level exposure to ionising radiation in nuclear workers (INWORKS): updated findings from an international cohort study
Klervi Leuraud, PhDa klervi.leuraud@irsn.fr ∙ Dominique Laurier, PhDa ∙ Michael Gillies, MScb ∙ Richard Haylock, PhDb ∙ Kaitlin Kelly-Reif, PhDc ∙ Stephen Bertke, PhDc∙ et al. August 30, 2024 Link: https://www.thelancet.com/journals/lanhae/article/PIIS2352-3026(24)00240-0/abstract
Summary
Background
A major update to the International Nuclear Workers Study (INWORKS) was undertaken to strengthen understanding of associations between low-dose exposure to penetrating forms of ionising radiation and mortality. Here, we report on associations between radiation dose and mortality due to haematological malignancies.
Methods
We assembled a cohort of 309 932 radiation-monitored workers (269 487 [87%] males and 40 445 [13%] females) employed for at least 1 year by a nuclear facility in France (60 697 workers), the UK (147 872 workers), and the USA (101 363 workers). Workers were individually monitored for external radiation exposure and followed-up from Jan 1, 1944, to Dec 31, 2016, accruing 10·72 million person-years of follow-up. Radiation-mortality associations were quantified in terms of the excess relative rate (ERR) per Gy of radiation dose to red bone marrow for leukaemia excluding chronic lymphocytic leukaemia (CLL), as well as subtypes of leukaemia, myelodysplastic syndromes, non-Hodgkin and Hodgkin lymphomas, and multiple myeloma. Estimates of association were obtained using Poisson regression methods.
Findings
The association between cumulative dose to red bone marrow, lagged 2 years, and leukaemia (excluding CLL) mortality was well described by a linear model (ERR per Gy 2·68, 90% CI 1·13 to 4·55, n=771) and was not modified by neutron exposure, internal contamination monitoring status, or period of hire. Positive associations were also observed for chronic myeloid leukaemia (9·57, 4·00 to 17·91, n=122) and myelodysplastic syndromes alone (3·19, 0·35 to 7·33, n=163) or combined with acute myeloid leukaemia (1·55, 0·05 to 3·42, n=598). No significant association was observed for acute lymphoblastic leukaemia (4·25, –4·19 to 19·32, n=49) or CLL (0·20, –1·81 to 2·21, n=242). A positive association was observed between radiation dose and multiple myeloma (1·62, 0·06 to 3·64, n=527) whereas minimal evidence of association was observed between radiation dose and non-Hodgkin lymphoma (0·27, –0·61 to 1·39, n=1146) or Hodgkin lymphoma (0·60, –3·64 to 4·83, n=122) mortality.
Interpretation
This study reports a positive association between protracted low dose exposure to ionising radiation and mortality due to some haematological malignancies. Given the relatively low doses typically accrued by workers in this study (16 mGy average cumulative red bone marrow dose) the radiation attributable absolute risk of leukaemia mortality in this population is low (one excess death in 10 000 workers over a 35-year period). These results can inform radiation protection standards and will provide input for discussions on the radiation protection system.
Funding
National Cancer Institute, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Institut de Radioprotection et de Sûreté Nucléaire, Orano, Electricité de France, UK Health Security Agency.
Translation
For the French translation of the abstract see Supplementary Materials section.
References – (many)
Labour Government must give ‘absolute commitment’ to nuclear test veterans
The Nuclear Free Local Authorities have called on the new Labour
Government to give an ‘absolute commitment’ to righting the injustice
and recompensing the suffering of British nuclear test veteran community
which has lasted for over seventy years.
NFLA 29th Aug 2024
Concerns raised for health professionals exposed to radiation at work
https://www.skynews.com.au/lifestyle/health/concerns-raised-for-health-professionals-exposed-to-radiation-at-work/video/6216ed317c9b0392811b3e850b8c5f23 18 Aug 24
The rise of x-ray-guided operations has raised concerns for health professionals who are now being exposed to more radiation at work.
The game-changing procedures have reduced the need for serious surgeries, improving health outcomes for many Australians with heart problems and other diseases.
“There are multiple steps that the hospitals take to reduce the exposure, however, a certain degree of exposure is inevitable,” said Interventional and Instructional Cardiologist Dr Samer Noaman.
TODAY. Low dose ionising radiation as a cause of illness and death
It’s not fashionable to talk about low level radiation as causing illness. If it gets mentioned at all, well, we tentatively state low level radiation as linked with or associated with illness.
Nice and vague. We all know that you can’t respectably experiment on humans, to get absolute proof.
The nuclear lobby doesn’t mind admitting to the harmful effects of immediate high doses of ionising radiation. Those effects are so bad for the relatively few individuals that suffer them, – why it almost seems to prove that low doses are OK, (even good for you as the “hormesis” fans claim)! It’s easier to dwell on, and deplore the effects of high dose radiation on one person, which is, for some unknown reason, now the most popular topic on my nuclear-news website.
What is ignored, especially by the nuclear lobby, is the collective effect over time, of low level radiation. Nobody seems to have a figure for this. But there have been several thoroughly researched epidemiological studies, showing the harmful effects on exposed populations. The most recent was published in the British Medical Journal (BMJ Aug 16, 2023 accessible free of charge).
The thing is – people can get their head around the idea of one individual having a painful illness and death.
The less dramatic thought is – say for example – if 10 million people were exposed over time to low level radiation, and their risk of fatal cancer was increased from the normal risk of 5%, by another 8% (as the BMJ study showed) that would result in one million three hundred thousand fatal cancers.
When we pause to think about this less exciting information about slowly developing illness of great numbers of people – it’s pretty serious!
So this is the collective effect of low level radiation – that doesn’t get talked about.
One huge study recently has been based on dual research – i.e. on epidemiological research and experimentation on mice. This kind of study is similar to the work of Sir Richard Doll in the 1950s proving that cigarette-smoking causes cancer.
Now the corporate world prefers terms like “linked” and “associated with’ – terms that blur the reality of the scandals of environmental pollution and health. And there’s no bigger scandal than the pervasive lie that low level ionising radiation does not matter.
Long-run exposure to low-dose radiation reduces cognitive performance
Science Direct, Journal of Environmental Economics and Management, Benjamin Elsner , Florian Wozny Volume 118, March 2023, 102785
Abstract
This paper examines the effect of long-run exposure to low-dose radiation on cognitive performance. We focus on the fallout from the Chernobyl accident, which increased the level of ground radiation in large parts of Europe. To identify a causal effect, we exploit unexpected rainfall patterns in a critical time window after the disaster as well as the trajectory of the radioactive plume, which determine local fallout but have no plausible direct effect on test scores. Based on geo-coded survey data from Germany, we show that people exposed to higher radiation perform significantly worse in standardized cognitive tests 25 years later. An increase in initial exposure by one standard deviation reduces cognitive test scores by around 5% of a standard deviation.
1. Introduction
The last 40 years have seen a drastic increase in radiation exposure. Today, the average person in Europe and America receives about twice the annual dose of radiation compared with in 1980 (NCRP, 2009). This increase is almost entirely due to man-made sources of radiation, such as medical procedures, nuclear power and nuclear weapons. Procedures such as CT scans, X-rays, mammograms or radiotherapy expose patients to low doses of radiation, and their use has been steadily increasing over the past decades. Moreover, the fallout from nuclear disasters such as Chernobyl and Fukushima or a nuclear bomb can expose people thousands of miles from the epicenter.
Medical research shows that subclinical radiation can damage human cells, which has potential knock-on effects on health and cognition and that these effects may occur at all ages. The existing literature has mostly focused on the effect of in-utero exposure, documenting significant adverse effects of radiation exposure during pregnancy on education and labor market outcomes many years later (Almond et al., 2009, Heiervang et al., 2010, Black et al., 2019). However, there is little evidence on the long-term effects of exposure to low-dose radiation after birth. Documenting such effects is important, not least because of the number of potentially affected people: the number of people alive at any one point is substantially greater than the number of fetuses in the womb.
In this paper, we exploit plausibly exogenous variation of the Chernobyl fallout to study the impact of exposure to low-dose radiation on cognitive test scores 25 years after the disaster. We focus on Germany, which received a significant amount of fallout due to weather conditions in the aftermath of the disaster in 1986. Because of the long half-life of the radioactive matter, people who continuously lived in areas with higher initial fallout have been exposed to higher radiation levels for over 30 years. For people exposed after birth, there are two plausible biological channels through which radiation can affect cognitive test scores: a direct effect on the brain because radiation can damage brain cells, and an indirect effect through general health, which may lead to fatigue, thus reducing test performance.
Our dataset – the National Educational Panel Study (NEPS), a representative geo-coded survey – allows us to link fine-grained data on fallout levels in a person’s municipality of residence since 1986 to a battery of standardized cognitive tests done 25 years after the disaster. At the time of the disaster, over half of our sample were adolescents or adults, allowing us to estimate the long-run effect of exposure at these ages.
The central identification challenge is a potential correlation between the local amount of radiation and residential sorting. The local amount of radiation is driven by a combination of several factors, for example wind speed, rainfall, altitude or soil composition. Some of these factors may have also influenced residential sorting prior to 1986, thus potentially leading to omitted variable bias. ………………………………………………………………………
Our central finding is that people exposed to higher levels of radiation from 1986 onward performed significantly worse in cognitive tests 25 years later. A one-standard-deviation higher initial exposure in 1986 reduces test scores by around 5% of standard deviation. Over the course of 25 years, the additional radiation dose of a one-standard-deviation higher initial exposure is roughly equivalent to the dose from 6 chest X-rays or 1.65 mammograms, which indicates that the long-term effects of low-dose radiation can be non-trivial. An additional analysis shows that these effects are not driven by selective migration after the Chernobyl disaster.
This result feeds into two domains of the public debate on radiation. One is about the costs and benefits of nuclear power in many countries. While nuclear power offers the advantage of supplying vast amounts of energy at zero carbon emissions, it comes with the cost of potential disasters. In the last 35 years we have seen two major disasters. Given the proliferation of nuclear power along with the emergence of conflicts like the current war in Ukraine, it is possible that more nuclear disasters may follow. Our results, along with those in other studies, point to significant external costs of nuclear power generation and document an important effect of nuclear disasters on the population. Another public debate, more broadly, deals with exposure to man-made radiation. For example, today the average American receives twice the annual radiation dose compared to in 1980, which is mainly due to medical procedures such as X-rays, mammograms or CT scans (NCRP, 2009). Our results can inform the debate about the long-term consequences of this increase in radiation exposure. The radiation dose from medical procedures is similar to the additional radiation dose Germans in highly affected areas received after Chernobyl. And although these procedures offer high benefits for patients, our findings suggest that they come with a health cost due to a higher radiation exposure.
With this paper, we contribute to three strands of literature. First, our findings contribute to the literature on the effect of pollution on human capital. This literature has produced compelling results for two types of effects. One strand focuses on exposure during pregnancy or early childhood and documents adverse long-term effects of pollution. Another strand focuses on adults and estimates the short-run effect of fluctuations in pollution on outcomes such as productivity, test scores and well-being.1 Our study, in contrast, examines the long-run effects among people exposed after early childhood. These effects are important, not least because of the number of people affected. The cohorts in our sample represent around 24 million people, compared to 200,000 children who were in the womb at the time of Chernobyl. Even if the individual effect is smaller for people exposed after early childhood, our study shows that the environment can have adverse consequences for large parts of the population and, therefore, exposure after early childhood deserves more attention in the literature.
Second, this paper adds new evidence to the emerging literature on pollution and cognitive functioning……………………………………………………….
……………………., this paper contributes to the broader literature on the effects of low-dose radiation. Two recent reviews of the epidemiological literature by Pasqual et al. (2020) and Collett et al. (2020) conclude that there is significant evidence that exposure to low-dose radiation early in life has negative effects on health and cognitive performance.
……………………………….. our results point to even wider-reaching adverse effects of nuclear disasters. Germany is over 1200 km from Chernobyl, and our study shows that large parts of the population have been adversely affected.
2. Historical background and review of the medical literature
2.1. The Chernobyl disaster and its impact in Germany
2.1. The Chernobyl disaster and its impact in Germany
The Chernobyl nuclear disaster in 1986 is one of the two largest nuclear accidents in history. It occurred after a failed simulation of a power cut at a nuclear power plant in Chernobyl/Ukraine on April 26, 1986, which triggered an uncontrolled chain reaction and led to the explosion of the reactor. In the two weeks following the accident, several trillion Becquerel of radioactive matter were emitted from the reactor, stirred up into the atmosphere, and – through strong east winds – carried all over Europe.2 The most affected countries were Belarus, Ukraine as well as the European part of Russia, although other regions, such as Scandinavia, the Balkans, Austria and Germany also received considerable amounts of fallout. The only other accident with comparable levels of fallout was the Fukushima disaster in Japan in 2011 (Yasunari et al., 2011).
Post-Chernobyl radiation in Germany.
………………………………….From 1986 to 1989, the governments of West and East Germany rolled out a comprehensive program to measure radiation across the country. At over 3,000 temporary measuring points, gamma spectrometers measured the radiation of Cs137. Based on the decay of the isotopes, all measurements were backdated to May 1986.
………………………………………….Radiation exposure of the German population.
Humans can be exposed to radiation in three ways, namely through inhaling radioactive particles, ingesting contaminated foods, as well as external exposure, whereby radiation affects the body if a person is present in a place with a given level of radioactivity in the environment. Exposure to radiation through air and ground can be directly assigned to – and therefore be strongly correlated with – a person’s place of residence ……………………………………………………………………………………………………………………………..
Information about the nuclear disaster and reactions of the German public
……………………………………………………………………………………. 2.2. Effects of radiation on the human body
The effect of radiation on the human body is by no means limited to high-dose radiation, such as the one experienced by survivors of nuclear bombs or clean-up workers at the site of the Chernobyl reactor. The medical literature has shown that exposure to subclinical radiation – at doses most people are exposed to, for example due to background radiation, medical procedures, or the fallout from Chernobyl in large parts of Europe – can negatively affect cognition, physical health and well-being. Moreover, while the effects of subclinical radiation may be strongest during pregnancy and early childhood, radiation exposure can have adverse effects throughout a person’s life.
Plausible channels.
Radiation exposure can affect cognitive test scores through four types of channels:
- 1.A direct effect on cognition, as radiation can impair the functioning of brain cells.
- 2.An indirect effect through physical health; radiation can impair the functioning of organs and lead to greater fatigue, which in turn may negatively affect test scores.
- 3.An indirect effect through mental health; a review by Bromet et al. (2011) suggests that people’s worry about the long-term consequences of radiation for physical health may lower their well-being and lead to poor mental health.
- 4.Indirect effects through behavioral responses, such as internal migration or changes in life style. To the extent that these effects reflect avoidance behavior, they will dampen the negative biological effects.5
In the following, we summarize the evidence from two types of study: one based on observational studies with humans, the other based on experimental studies with mice and rats. While both arguably have their weaknesses – one is non-experimental, the other has limited external validity – together they show that an effect of radiation on cognitive test scores is biologically plausible.
Observational studies.
The effect of radiation on cognitive performance is an active field of research in radiobiology and medicine. Radiation affects the human body through ionization, a process that damages the DNA and can lead to the dysfunction or death of cells (Brenner et al., 2003). Until the 1970s the human brain was considered radio-resistant, that is, brain cells were assumed to be unaffected by radiation. This view changed when lasting cognitive impairments were found in cancer patients who underwent radiotherapy. Studies find cognitive impairments among 50%–90% of adult brain cancer patients who survive more than six months after radiotherapy. The cognitive impairment can manifest itself in decreased verbal and spatial memory, lower problem-solving ability and decreased attention, and is often accompanied by fatigue and changes in mood ……………………………………………….
Laboratory evidence on rats and mice.
The experimental evidence with rodents confirms the evidence found among human cancer patients. Rats who were treated with brain irradiation experience a reduction in cognitive ability, although the biological processes differ between young and old rats………………………………………
While these studies confirm that radiation can plausibly affect cognitive functioning across the life cycle, they are mostly based on once-off radiation treatments. In contrast, after Chernobyl, the German population was constantly exposed to higher ground radiation for many years. A recent experiment on mice by Kempf et al. (2016) is informative about the effect of regular exposure to low-dose radiation. Among mice who were exposed for 300 days, the researchers detected a decrease in cognitive functioning and a higher incidence of Alzheimer’s disease.
Impact on overall health……………………………………….
3. Data and descriptive statistics…………………………………………………..
3.1. The NEPS data
Our main data source is the NEPS, a rich representative dataset on educational trajectories in Germany. ………………………………………………………………………………………………….
3.2. Estimation sample
Our sample includes all survey participants who were born before Chernobyl. We exclude participants born after Chernobyl because the survey only sampled birth cohorts up to December 1986, leaving us with few participants who were born after Chernobyl. Moreover, because we are interested in the effect of post-natal exposure, excluding them ensures that our estimates are not confounded by exposure in utero, which operates through a different biological channel. ……………………………………………………………………………………………………………………………………..
3.3. Cognitive tests………………………………………………………………………………………………………
3.4. Municipality- and County-level Data
Data on ground deposition……………………………………………………………………………………………
Linkage between individual and regional data.………………………………………………………………………..
Additional data.…………..
3.5. Descriptive statistics………………………………………………………………………………………………………………………………………..
4. Empirical strategy
4.1. Empirical model………………………………………………………………………………………
4.2. Identification challenge and balancing checks……………………………………………………………………………………
4.3. Instrumental variable strategy……………………………
IV component I: local rainfall during a critical time window.………………………………………………………………………………….
IV component II: available radioactive matter in the plume……………………………………………………………
First stage and instrument relevance………………………………………………………………………………..
Instrument validity………………………………………………………………………………………………………………
5. Radiation and cognitive skills: Results
5.1. The effect of initial exposure on cognitive performance………………………………………………………………….
5.2. The effect of average exposure,1986–2010…………………………………………………
5.3. Internal migration as a potential channel………………………………………………………………
5.4. Effect magnitude and discussion…………………………………………………………………
5.5. Robustness checks………………………………………………………………………..
6. Conclusion
In this paper, we have shown that radiation – even at subclinical doses – has negative long-term effects on cognitive performance………………………………………………………………………………………..
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Appendix A. Supplementary data………………………………….. more https://www.sciencedirect.com/science/article/pii/S0095069623000037
Red Cross Hospital in Japan continuing to treat nuclear bomb victims – the hibakusha
The waiting room of the Red Cross hospital in downtown Hiroshima is always
crowded. Nearly every available seat is occupied, often by elderly people
waiting for their names to be called. Many of these men and women don’t
have typical medical histories, however. They are the surviving victims of
the American atomic bomb attack 79 years ago.
Not many Americans have Aug. 6 circled on their calendars, but it’s a day that the Japanese can’t forget. Even now, the hospital continues to treat, on average, 180
survivors — known as hibakusha — of the blasts each day.
When the United States dropped an atomic weapon on Hiroshima on Aug. 6, 1945, the
entire citizenries of both countries were working feverishly to win World
War II. For most Americans, the bomb represented a path to victory after
nearly four relentless years of battle and a technological advance that
would cement the nation as a geopolitical superpower for generations. Our
textbooks talk about the world’s first use of a nuclear weapon.
Many today in Hiroshima and Nagasaki, where the United States detonated a bomb
just three days later, talk about how those horrible events must be the
last uses of nuclear weapons.
New York Times 6th Aug 2024
https://www.nytimes.com/interactive/2024/08/06/opinion/hiroshima-nagasaki-atomic-bombing.html
The Impact of Nuclear Weapons on Children
Content warning: This report includes graphic stories, illustrations and photographs of extreme violence committed against children; detailed descriptions of children’s injuries, suffering and deaths; references to mental illness, suicide and child neglect; and stories of harm inflicted on pregnant women resulting in miscarriages and stillbirths.
Contents
Part I The Children of Hiroshima and Nagasaki
Part II Children Harmed by Nuclear Testing
Every day, children are killed or injured in armed conflicts around the world. Thousands of children – including many babies – are now counted among the dead in the ongoing wars in Gaza and Ukraine: a blight on humanity.
In both cases, the main perpetrators of violence against children are states armed with nuclear weapons; and in any war involving one or more such states, there is an inherent risk of nuclear catastrophe.
As this report shows in compelling and often gut-wrenching detail, it is children who would suffer the most in the event of a nuclear attack against a city today.
The Impact of Nuclear Weapons on Children is a dire warning to the governments of all nuclear-armed states and to the global public that urgent action is needed to rid the world of nuclear weapons.
By sharing the stories of children killed or injured in the US atomic bombings of Hiroshima and Nagasaki in 1945 and of children harmed by nuclear tests, we hope to honour them and ensure that no one else ever suffers as they have.
Hon. Melissa Parke, Executive Director, ICAN, August 2024
Executive Summary
Nuclear weapons are designed to destroy cities; to kill and maim whole populations, children among them.
In a nuclear attack, children are more likely than adults to die or suffer severe injuries, given their greater vulnerability to the effects of nuclear weapons: heat, blast and radiation. The fact that children depend on adults for their survival also places them at higher risk of death and hardship in the aftermath of a nuclear attack, with support systems destroyed.
Tens of thousands of children were killed when the United States detonated two relatively small nuclear weapons (by today’s standard) over the Japanese cities of Hiroshima and Nagasaki in 1945.
Many were instantly reduced to ash and vapour. Others died in agony minutes, hours, days or weeks after the attacks from burn and blast injuries or acute radiation sickness. Countless more died years or even decades later from radiation-related cancers and other illnesses. Leukaemia – cancer of the blood – was especially prevalent among the young.
In Hiroshima and Nagasaki, the scenes of devastation were apocalyptic: Playgrounds scattered with the dead bodies of young girls and boys. Mothers cradling their lifeless babies. Children with their intestines hanging out of their bellies and strips of skin dangling from their limbs.
At some of the schools close to ground zero, the entire student population of several hundred perished in an instant. At others, there were but a few survivors. In Hiroshima, thousands of school students were working outside to create firebreaks on the morning of the attack. Approximately 6,300 of them were killed.
Those children who, by chance, escaped death carried with them severe physical and psychological scars throughout their lifetimes. What they witnessed and experienced on 6 August and 9 August 1945 and in the days that followed was permanently seared into their memories.
Thousands of children lost one or both parents, as well as siblings. Some “A-bomb orphans” were left to roam the streets, with orphanages exceeding capacity.
Many of the babies who were in their mothers’ wombs at the time of the atomic bombings were also harmed as a result of their exposure to ionising radiation. They had a greater risk of dying soon after birth or suffering from congenital abnormalities such as brain damage and microcephaly, as well as cancers and other illnesses later in life.
Pregnant women in Hiroshima and Nagasaki also experienced higher rates of spontaneous abortions and stillbirths.
In communities around the world exposed to fallout from nuclear testing, children have experienced similar harm from radiation.
Since 1945, nuclear-armed states have conducted more than two thousand nuclear test explosions at dozens of locations, dispersing radioactive material far and wide.
Among the general population, children and infants have been the most severely affected, due to their higher vulnerability to the effects of ionising radiation. Young children are three to five times more susceptible to cancer in the long term than adults from a given dose of radiation, and girls are particularly vulnerable.
In the Marshall Islands, where the United States conducted 67 nuclear tests, children played in the radioactive ash that fell from the sky, unaware of the danger. They called it “Bikini snow” – a reference to the atoll where many of the explosions took place. It burned their skin and eyes, and they quickly developed symptoms of acute radiation sickness.
For decades after the tests, women in the Marshall Islands gave birth to severely deformed babies at unusually high rates. Those born alive rarely survived more than a few days. Some had translucent skin and no discernible bones. They would refer to them as “jellyfish babies”, for they could scarcely be recognised as human beings.
Similar stories have been told by people living downwind or downstream of nuclear test sites in the United States, Kazakhstan, Ma’ohi Nui, Algeria, Kiribati, China, Australia and elsewhere.
We have a collective moral duty to honour the memories of the thousands of children killed in Hiroshima and Nagasaki, as well as those harmed by the development and testing of nuclear weapons globally. And we must pursue the goal of a nuclear-weapon-free world with determination and urgency, lest there be any more victims, young or old.
Under international humanitarian law and the Convention on the Rights of the Child, governments have a legal obligation to protect children against harm in armed conflict. To fulfil this obligation, it is imperative that they work together now to eliminate the scourge of nuclear weapons from the world.
In this report, we describe how nuclear weapons are uniquely harmful to children, based on the experiences of children in Hiroshima and Nagasaki and those living near nuclear test sites. We share their first-hand testimonies and depictions of the toll of nuclear weapons on their lives. And we explain how the ever-present fear of nuclear war – the possibility that entire cities might be destroyed at any given moment – causes psychological harm to children everywhere.
Finally, we make an urgent appeal to all governments to protect current and future generations of children by eliminating nuclear weapons, via the landmark UN Treaty on the Prohibition of Nuclear Weapons, which entered into force in 2021.
Key findings
So long as nuclear weapons exist in the world, there is a very real risk that they will be used again, and that risk at present appears to be increasing.
In the event of their use, it is all but certain that many thousands of children – perhaps hundreds of thousands or more – would be counted among the dead and injured, and they would suffer in unique ways and out of proportion to the rest of the population.
In a nuclear attack, children would be more likely than adults:
- To die from burn injuries, as their skin is thinner and more delicate and burns deeper, more quickly and at a lower temperature;
- To die from blast injuries, given the relative frailty of their smaller bodies;
- To die from acute radiation sickness, as they have more cells that are growing and dividing rapidly and are significantly more vulnerable to radiation effects;
- To be unable to free themselves from collapsed and burning buildings or take other steps in the aftermath that would increase their chances of survival;
- To suffer from leukaemia, solid cancers, strokes, heart attacks and other illnesses years later as a result of the delayed effects of radiation damage to their cells; and
- To suffer privation in the aftermath of the attacks, as well as psychological trauma leading to mental disorders and suicide.
Furthermore, babies who were in their mothers’ wombs at the time of the attack would be at greater risk of:
- Death soon after birth or in early childhood;
- Microcephaly, accompanied by intellectual disability, given the higher vulnerability of the developing brain to radiation damage;
- Other developmental abnormalities;
- Growth impairment due to the reduced functioning of the thyroid; and
- Cancers and other radiation-related illnesses during childhood or later in life.
These horrifying realities should have profound implications for policy-making in countries that currently possess nuclear weapons or those that support their retention as part of military alliances.
They should also prompt organisations dedicated to the protection of children and the promotion of their rights to work to address the grave global threat posed by nuclear weapons.
While children played no part in developing these doomsday devices, it is children who would suffer the most in the event of their future use – one of the myriad reasons why such weapons must be urgently eliminated………………………………………………………………………………………………………………………………………………………….. more https://www.icanw.org/children?utm_campaign=2024_children_launch_an&utm_medium=email&utm_source=ican
Link between unexploded munitions in oceans and cancer-causing toxins determined
by Anisa S. Jimenez, Phys Org, February 18, 2009
During a research trip to Puerto Rico, ecologist James Porter took samples from underwater nuclear bomb target USS Killen, expecting to find evidence of radioactive matter – instead he found a link to cancer. Data revealed that the closer corals and marine life were to unexploded bombs from the World War II vessel and the surrounding target range, the higher the rates of carcinogenic materials.
“Unexploded bombs are in the ocean for a variety of reasons – some were duds that did not explode, others were dumped in the ocean as a means of disposal,” said Porter. “And we now know that these munitions are leaking cancer-causing materials and endangering sea life.”
Data has been gathered since 1999 on the eastern end of the Isla de Vieques, Puerto Rico – a land and sea area that was used as a naval gunnery and bombing range from 1943-2003. Research revealed that marine life including reef-building corals, feather duster worms and sea urchins closest to the bomb and bomb fragments had the highest levels of toxicity. In fact, carcinogenic materials were found in concentrations up to 100,000 times over established safe limits. This danger zone covered a span of up to two meters from the bomb and its fragments.
According to research conducted in Vieques, residents here have a 23% higher cancer rate than do Puerto Rican mainlanders. Porter said a future step will be “to determine the link from unexploded munitions to marine life to the dinner plate.”….. https://phys.org/news/2009-02-link-unexploded-munitions-oceans-cancer-causing.html
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