The dangers of ionizing radiation due to radioactivity and X-rays were not immediately recognized.
Early health dangers
Radioactive decay
Radioactive decay | Early health dangers
The dangers are not immediately recognized. Sorry. I cannot find the answer based on the context. Burns, hair loss to mention a few Sorry. I cannot find the answer based on the context.
who was lise meitner?
user
She was an Austrian-Swedish physicist.
assistant
in which country did she live in her early days?
user
In the Leopoldstadt district of Vienna
assistant
any particular educational institution that she attended as a student?
user
University of Vienna
assistant
why did she have to flee from germany?
user
Because she lost her Austrian citizenship.
assistant
why?
user
Sorry. I cannot find the answer based on the context.
assistant
can you mention any of her contributions?
user
She completed the work on beta ray spectrum that she had begun with Hahn and Baeyer, and also her own study of the uranium decay chain.
assistant
could you please elaborate the last reaction?
user
It refers to a series of radioactive decays of different radioactive decay products as a sequential series of transformations - a.k.a. "radioactive cascade".
assistant
can you mention any health hazard caused by this decay?
user
The dangers of ionizing radiation due to radioactivity and X-rays were not immediately recognized.
Radioactive decay | Early health dangers
Radioactive materials produce ionizing radiation which may be very harmful to living organisms. Damage from even a short exposure to radioactivity may have long term adverse health consequences. Exposure may occur from nuclear fallout when nuclear weapons are detonated or nuclear containment systems are compromised. During World War II, the United States Army Air Forces dropped atomic bombs on the Japanese cities of Hiroshima and Nagasaki, leading to extensive contamination of food, land, and water. In the Soviet Union, the Mayak industrial complex (otherwise known as Chelyabinsk-40 or Chelyabinsk-65) exploded in 1957. The Kyshtym disaster was kept secret for several decades.
Anthropogenic hazard | Radioactive materials
Visceral fear is not widely aroused by, for example, the daily emissions from coal burning, although, as a National Academy of Sciences study found, this causes 10,000 premature deaths a year in the US population of 317,413,000. Medical errors leading to death in U.S. hospitals are estimated to be between 44,000 and 98,000. It is "only nuclear radiation that bears a huge psychological burden – for it carries a unique historical legacy".
Radioactive contamination | Social and psychological effects
The health risks – particularly the development of solid cancers in organs – rise proportionally with exposure" says Richard R. Monson, associate dean for professional education and professor of epidemiology, Harvard School of Public Health, Boston.
Radiation hormesis | Statements by leading nuclear bodies
The total ingested dose was largely from iodine and, unlike the other fission products, rapidly found its way from dairy farms to human ingestion. Similarly in dose reconstruction, for those evacuated at different times and from various towns, the inhalation dose was dominated by iodine (40%), along with airborne tellurium (20%) and oxides of rubidium (20%) both as equally secondary, appreciable contributors. Long term hazards such as caesium tends to accumulate in vital organs such as the heart, while strontium accumulates in bones and may thus be a risk to bone-marrow and lymphocytes. Radiation is most damaging to cells that are actively dividing.
Chernobyl disaster | Effects of main harmful radionuclides
In health physics, neutron radiation is a type of radiation hazard. Another, more severe hazard of neutron radiation, is neutron activation, the ability of neutron radiation to induce radioactivity in most substances it encounters, including bodily tissues. This occurs through the capture of neutrons by atomic nuclei, which are transformed to another nuclide, frequently a radionuclide. This process accounts for much of the radioactive material released by the detonation of a nuclear weapon. It is also a problem in nuclear fission and nuclear fusion installations as it gradually renders the equipment radioactive such that eventually it must be replaced and disposed of as low-level radioactive waste.
Neutron radiation | Health hazards and protection
Radioactive contamination is a potential danger for living organisms and results in external hazards, concerning radiation sources outside the body, and internal dangers, as a result of the incorporation of radionuclides inside the body (often by inhalation of particles or ingestion of contaminated food). In humans, single doses from 0.25 Sv produce first anomalies in the amount of leukocytes. This effect is accentuated if the absorbed dose is between 0.5 and 2 Sv, in whose first damage, nausea and hair loss are suffered. The strip ranging between 2 and 5 Sv is considered the most serious and include bleeding, ulcers and risk of death; values exceeding 5 Sv involve immediate death.
Bioremediation of radioactive waste | Ecological and human health consequences
Decay heat accidents are where the heat generated by the radioactive decay causes harm. In a large nuclear reactor, a loss of coolant accident can damage the core: for example, at Three Mile Island a recently shutdown (SCRAMed) PWR reactor was left for a length of time without cooling water. As a result, the nuclear fuel was damaged, and the core partially melted. The removal of the decay heat is a significant reactor safety concern, especially shortly after shutdown. Failure to remove decay heat may cause the reactor core temperature to rise to dangerous levels and has caused nuclear accidents.
Nuclear and radiation accidents and incidents | Decay heat
Over longer periods of exposure to radiation, cancer becomes the main health risk. Long term radiation exposure can also lead to in utero effects on human development and transgenerational genetic damage.
Nuclear holocaust | Nuclear fallout
As radon decays, it produces radioactive decay products. If the contaminated dust of these "radon daughters" are inhaled, they can lodge in the lungs and increase the risk of developing lung cancer. Iodine in food is absorbed by the body and preferentially concentrated in the thyroid where it is needed for the functioning of that gland. When Iodine-131 is present in high levels in the environment from hydraulic fracturing flowback and blowouts, it can be absorbed through contaminated food and water, and will also accumulate in the thyroid. As it decays, it may cause damage to the thyroid. The primary risk from exposure to high levels of iodine-131 is the chance occurrence of radiogenic thyroid cancer in later life.
Hydraulic fracturing and radionuclides | Health impact
About 350–600 cattle were affected by superficial burns and localized temporary loss of dorsal hair; the army later bought 75 most affected cows as the discolored regrown hair lowered their market value. The cows were shipped to Los Alamos and Oak Ridge, where they were observed. They healed, now sporting large patches of white fur; some looked as if they had been scalded. The fallout produced by the Castle Bravo test was unexpectedly strong. A white snow-like dust, nicknamed by the scientists "Bikini snow" and consisting of contaminated crushed calcined coral, fell for about 12 hours upon the Rongelap Atoll, depositing a layer of up to 2 cm.
Radiation burn | Radioactive fallout
The caesium precipitated with ferric ferrocyanide (Prussian blue) would be the only waste requiring special burial sites. The aim is to get annual exposure from the contaminated environment down to 1 mSv above background. The most contaminated area where radiation doses are greater than 50 mSv/year must remain off limits, but some areas that are currently less than 5 mSv/year may be decontaminated, allowing 22,000 residents to return. Caesium-137 in the environment is substantially anthropogenic (human-made). Caesium-137 is produced from the nuclear fission of plutonium and uranium, and decays into barium-137. Before the construction of the first artificial nuclear reactor in late 1942 (the Chicago Pile-1), caesium-137 had not occurred on Earth in significant amounts for about 1.7 billion years.
Caesium-137 | Fukushima Daiichi disaster
CBS News reported that the number of doses of potassium iodide available to the public in Japan was inadequate to meet the perceived needs for an extensive radioactive contamination event. Caesium-137 is also a particular threat because it behaves like potassium and is taken up by cells throughout the body. Additionally, it has a long, 30-year half-life. Cs-137 can cause acute radiation sickness, and increase the risk for cancer because of exposure to high-energy gamma radiation. Internal exposure to Cs-137, through ingestion or inhalation, allows the radioactive material to be distributed in the soft tissues, especially muscle tissue, exposing these tissues to the beta particles and gamma radiation and increasing cancer risk.
Radiation effects from the Fukushima Daiichi nuclear disaster | Isotopes of concern
The exposure to fallout has been linked to increase the likelihood of several types of cancer such as leukemia and thyroid cancer. The relationship between I-131 levels and thyroid cancer is continuing to be researched. There are also correlations between fallout exposure levels and diseases such as thyroid disease like hypothyroidism. Populations of the Marshall Islands that received significant exposure to radionuclides have a much greater risk of developing cancer. The Castle Bravo test detonation produced an explosion of approximately 15 megatons and populations neighboring the test site were exposed to high levels of radiation resulting in mild radiation sickness of many (nausea, vomiting, diarrhea).
Nuclear testing at Bikini Atoll | Health impacts
While most of the particles carried by nuclear fallout decay rapidly, some radioactive particles will have half-lives of seconds to a few months. Some radioactive isotopes, like strontium 90 and cesium 137, are very long lived and will create radioactive hot spots for up to 5 years after the initial explosion. Fallout and black rain may contaminate waterways, agriculture, and soil. Contact with radioactive materials can lead to radiation poisoning through external exposure or accidental consumption. In acute doses over a short amount of time radiation will lead to prodromal syndrome, bone marrow death, central nervous system death and gastrointestinal death.
Nuclear holocaust | Nuclear fallout
The majority of premature deaths caused by Chernobyl are expected to be the result of cancers and other diseases induced by radiation in the decades after the event. This will be the result of a large population (some studies have considered the entire population of Europe) exposed to relatively low doses of radiation increasing the risk of cancer across that population. Interpretations of the current health state of exposed populations vary. Therefore, estimates of the ultimate human impact of the disaster have relied on numerical models of the effects of radiation on health. Furthermore, the effects of low-level radiation on human health are not well understood, and so the models used, notably the linear no threshold model, are open to question.
Effects of the Chernobyl disaster | Human health effects Studies
This energy is roughly the weight of the alpha (4 u) divided by the weight of the parent (typically about 200 u) times the total energy of the alpha. By some estimates, this might account for most of the internal radiation damage, as the recoil nucleus is part of an atom that is much larger than an alpha particle, and causes a very dense trail of ionization; the atom is typically a heavy metal, which preferentially collect on the chromosomes. In some studies, this has resulted in an RBE approaching 1,000 instead of the value used in governmental regulations.
Alpha decay | Toxicity
The hazards associated with NORM are inhalation and ingestion routes of entry as well as external exposure where there has been a significant accumulation of scales. Respirators may be necessary in dry processes, where NORM scales and dust become air borne and have a significant chance to enter the body. The hazardous elements found in NORM are radium 226, 228 and radon 222 and also daughter products from these radionuclides. The elements are referred to as "bone seekers" which when inside the body migrate to the bone tissue and concentrate. This exposure can cause bone cancers and other bone abnormalities.
Naturally occurring radioactive material | Hazards
Hahn refused medical evaluation for radiation exposure. EPA scientists believe that Hahn's life expectancy may have been greatly shortened by his exposure to radioactivity, particularly since he spent long periods in the small, enclosed shed with large amounts of radioactive material and only minimal safety precautions, but he refused their recommendation that he be examined at the Enrico Fermi Nuclear Generating Station.
David Hahn | Creation of the neutron source
These mechanisms range from DNA, mRNA and protein repair, to internal lysosomic digestion of defective proteins, and even induced cell suicide—apoptosis Depending on the decay mode and the pharmacokinetics of an element (how the body processes it and how quickly), the threat due to exposure to a given activity of a radioisotope will differ. For instance iodine-131 is a short-lived beta and gamma emitter, but because it concentrates in the thyroid gland, it is more able to cause injury than caesium-137 which, being water soluble, is rapidly excreted through urine. In a similar way, the alpha emitting actinides and radium are considered very harmful as they tend to have long biological half-lives and their radiation has a high relative biological effectiveness, making it far more damaging to tissues per amount of energy deposited.
Radioactive waste | Pharmacokinetics
While the CDC has published one study that no human cancer has been seen as a result of exposure to natural or depleted uranium, exposure to uranium and its decay products, especially radon, are widely known and significant health threats. Exposure to strontium-90, iodine-131, and other fission products is unrelated to uranium exposure, but may result from medical procedures or exposure to spent reactor fuel or fallout from nuclear weapons. Although accidental inhalation exposure to a high concentration of uranium hexafluoride has resulted in human fatalities, those deaths were associated with the generation of highly toxic hydrofluoric acid and uranyl fluoride rather than with uranium itself.
Uranium | Effects and precautions
Issues related to identifying and tracking long-latency diseases have presented another stumbling block to reaching consensus on deaths beyond the immediate fatalities directly attributable to the initial reactor explosion and subsequent ARS. In the years since the accident, delayed, post-disaster deaths due to solid cancers, leukemia, and other long-latency diseases that might be attributable to the accident's release of radioactive debris have remained an ongoing concern. However, the streamlined standards, methods, and sustained research efforts needed to pinpoint, track, and tally such long-latency disease deaths have remained lacking—resulting in gaps in data and divergent estimates. (There is consensus for only one form of long-term physiological effect: thyroid cancer in those who consumed radioactive iodine as children.
Deaths due to the Chernobyl disaster | Long-latency diseases
A comprehensive 2005 study concluded that "the mental health impact of Chernobyl is the largest public health problem unleashed by the accident to date". Frank N. von Hippel, a U.S. scientist, commented on the 2011 Fukushima nuclear disaster, saying that "fear of ionizing radiation could have long-term psychological effects on a large portion of the population in the contaminated areas". Such great psychological danger does not accompany other materials that put people at risk of cancer and other deadly illness. Visceral fear is not widely aroused by, for example, the daily emissions from coal burning, although, as a National Academy of Sciences study found, this causes 10,000 premature deaths a year in the US.
Linear no-threshold model | Mental health effects
The concentration of radium and other daughter products build over time, with several years of excessive exposures. Therefore, from a liability standpoint an employee that has not had respiratory protection over several years could develop bone or other cancers from NORM exposure and decide to seek compensation such as medical expenses and lost wages from the oil company which generated the TENORM and the employer. Radium radionuclides emit alpha and beta particles as well as gamma rays. The radiation emitted from a radium 226 atom is 96% alpha particles and 4% gamma rays. The alpha particle is not the most dangerous particle associated with NORM.
Naturally occurring radioactive material | Hazards
The release of radioactive dust was caused by a human error during a blockage of pebbles in a pipe. Trying to restart the pebbles' movement by increasing gas flow led to stirring up of dust, always present in PBRs, which was then released, radioactive and unfiltered, into the environment due to an erroneously open valve. In spite of the limited amount of radioactivity released (0.1 GBq Co, Cs, Pa), a commission of inquiry was appointed. The radioactivity in the vicinity of the THTR-300 was finally found to result 25% from Chernobyl and 75% from THTR-300. The handling of this minor accident severely damaged the credibility of the German pebble-bed community, which lost significant support in Germany.
Pebble-bed reactor | Thorium high-temperature reactor
The primary fallout hazard is gamma radiation from short-lived radioisotopes, which represent the bulk of activity. Within 24 hours after the burst, the fallout gamma radiation level drops 60 times. Longer-life radioisotopes, typically caesium-137 and strontium-90, present a long-term hazard. Intense beta radiation from the fallout particles can cause beta burns to people and animals coming in contact with the fallout shortly after the blast. Ingested or inhaled particles cause an internal dose of alpha and beta radiation, which may lead to long-term effects, including cancer. The neutron irradiation of the atmosphere itself produces a small amount of activation, mainly as long-lived carbon-14 and short-lived argon-41.
Mushroom cloud | Radioisotopes
Of all the pregnant women who were close enough to be exposed to the "prompt" burst of intense neutron and gamma doses in the two cities, the total number of children born with microcephaly was below 50. No statistically demonstrable increase of congenital malformations was found among the "later conceived children" born to survivors of the nuclear detonations at Hiroshima and Nagasaki. The surviving women of Hiroshima and Nagasaki who could conceive and were exposed to substantial amounts of radiation went on and had children with no higher incidence of abnormalities than the Japanese average. The Baby Tooth Survey founded by the husband and wife team of physicians Eric Reiss and Louise Reiss, was a research effort focused on detecting the presence of strontium-90, a cancer-causing radioactive isotope created by the more than 400 atomic tests conducted above ground that is absorbed from water and dairy products into the bones and teeth given its chemical similarity to calcium.
Nuclear fallout | Long term
The primary radiation danger from pure depleted uranium is due to alpha particles, which do not travel far through air, and do not penetrate clothing. However, in a matter of a month or so, a sample of pure depleted uranium will generate small amounts of thorium-234 and protactinium-234, which emit the more penetrating beta particles at almost the same rate as the uranium emits alpha rays. This is because uranium-238 decays directly to thorium-234, which with a half-life of 24 days decays to protactinium-234, which in turn decays in a matter of hours to the long-lived uranium-234. A quasi-steady state is therefore reached within a few multiples of 24 days.
Depleted uranium | Radiological hazards
For introduction of radionuclides into organism, ingestion is the most important route. Insoluble compounds are not absorbed from the gut and cause only local irradiation before they are excreted. Soluble forms however show wide range of absorption percentages.
Nuclear fission product | Health concerns
With those who do shelter in place, and or evacuate, experiencing a total dose that would be negligible in comparison to someone who just went about their life as normal. Staying indoors until after the most hazardous fallout isotope, I-131 decays away to 0.1% of its initial quantity after ten half-lives – which is represented by 80 days in the care of I-131 cases, would make the difference between likely contracting thyroid cancer or escaping completely from this substance depending on the actions of the individual.
Effects of nuclear explosions on human health | Introduction
This is a drawback for its radioactive form which urges a search for more stable radioisotope materials. Commercial sources of radioactive caesium chloride are well sealed in a double steel enclosure. However, in the Goiânia accident in Brazil, such a source containing about 93 gram of CsCl, was stolen from an abandoned hospital and forced open by two scavengers. The blue glow emitted in the dark by the radioactive caesium chloride attracted the thieves and their relatives who were unaware of the associated dangers and spread the powder. This resulted in one of the worst radiation spill accidents in which 4 people died within a month from the exposure, 20 showed signs of radiation sickness, 249 people were contaminated with radioactive caesium chloride, and about a thousand received a dose exceeding a yearly amount of background radiation.
Caesium chloride | Toxicity
The Nuclear Regulatory Commission has not changed its opinion that there is no excess cancer risk from living near nuclear facilities.
Radiation and Public Health Project | Baby teeth
Exposed to radon, arsenic, radioactive dust, lead, and other toxic compounds, an estimated 10-15,000 deaths are expected from illnesses such as cancer. A barbed-wire fence was built around the local polluted lake in the 1980s, which no longer supports most life.
Oberrothenbach | History
It was calculated that even if hypothetical residents use water on the territory of radioactive waste dumps, the risks would be far below admissible levels. Such results can be explained by underground water purification during its hydrological transportation in surface waters, rains and snowmelt Primary health risks are off-site, posed by radionuclide contamination of agricultural lands and caused, among other factors, by groundwater migration through unconfined aquifer. This process eventually leads to internal irradiation of people using food from the contaminated areas.
Chernobyl groundwater contamination | Health risks
The Fernald School was the site of the 1946–53 joint experiments by Harvard University and MIT that exposed young male children to tracer doses of radioactive isotopes. Documents obtained in 1994 by the United States Department of Energy revealed the following details: The Advisory Committee on Human Radiation Experiments, reporting to the United States Department of Energy in 1994, reported on these experiments: In 1946, one study exposed seventeen subjects to radioactive iron. The second study, which involved a series of seventeen related subexperiments, exposed fifty-seven subjects to radioactive calcium between 1950 and 1953. It is clear that the doses involved were low and that it is extremely unlikely that any of the children who were used as subjects were harmed as a consequence.
Walter E. Fernald Developmental Center | Nuclear medicine research in children
This is, in part, due to self-damage of the crystals by alpha radiation, which weakens the lattice structure.
Radium bromide | Hazards
There are environmental concerns about radioactivity released from Hanford.
Anthropogenic hazard | Radioactive materials
Decay heat is the heat released as a result of radioactive decay. This heat is produced as an effect of radiation on materials: the energy of the alpha, beta or gamma radiation is converted into the thermal movement of atoms. Decay heat occurs naturally from decay of long-lived radioisotopes that are primordially present from the Earth's formation. In nuclear reactor engineering, decay heat continues to be generated after the reactor has been shut down (see SCRAM and nuclear chain reactions) and power generation has been suspended. The decay of the short-lived radioisotopes created in fission continues at high power, for a time after shut down.
Decay heat | Introduction
Like Fallon, Nevada, the nearby population is quite small, including approximately 9,000 children within 10 km of the plant. Over a one and a half year period, six cases of leukemia and one case of aplastic anemia were identified among children in this area, a 41.5 increase over national incidence rates. Four more cases were diagnosed during a subsequent two-year period. Public health officials began to suspect that high levels of airborne tritium “might be involved either directly or as an indicator for earlier releases of other short-lived radionuclides”.
Elbmarsch | Cancer cluster
Care must be taken to avoid using nuclei that undergo fission or neutron capture that causes radioactive decay of nuclei, producing gamma rays. Neutrons readily pass through most material, and hence the absorbed dose (measured in Grays) from a given amount of radiation is low, but interact enough to cause biological damage. The most effective shielding materials are water, or hydrocarbons like polyethylene or paraffin wax. Water-extended polyester (WEP) is effective as a shielding wall in harsh environments due to its high hydrogen content and resistance to fire, allowing it to be used in a range of nuclear, health physics, and defense industries.
Neutron radiation | Health hazards and protection
The phenomena of radioactive bioaccumulation, bioconcentration and biomagnification, however, are especially known to sea level. They are caused by the recruitment and retention of radioisotopes by bivalves, crustaceans, corals and phytoplankton, which then amounted to the rest of the food chain at low concentration factors.
Bioremediation of radioactive waste | Ecological and human health consequences
In addition to fission product poisons, other materials in the reactor decay to materials that act as neutron poisons. An example of this is the decay of tritium to helium-3. Since tritium has a half-life of 12.3 years, normally this decay does not significantly affect reactor operations because the rate of decay of tritium is so slow. However, if tritium is produced in a reactor and then allowed to remain in the reactor during a prolonged shutdown of several months, a sufficient amount of tritium may decay to helium-3 to add a significant amount of negative reactivity. Any helium-3 produced in the reactor during a shutdown period will be removed during subsequent operation by a neutron-proton reaction.
Neutron poison | Decay poisons
The heat removal is usually achieved through several redundant and diverse systems, and the heat is often dissipated to an 'ultimate heat sink' which has a large capacity and requires no active power, though this method is typically used after decay heat has reduced to a very small value. The main cause of release of radioactivity in the Three Mile Island accident was a pilot-operated relief valve on the primary loop which stuck in the open position. This caused the overflow tank into which it drained to rupture and release large amounts of radioactive cooling water into the containment building.
Nuclear and radiation accidents and incidents | Decay heat
Nuclear accidents can have dramatic consequences to their surroundings, but their global impact on cancer is less than that of natural and medical exposures. The most severe nuclear accident is probably the Chernobyl disaster. In addition to conventional fatalities and acute radiation syndrome fatalities, nine children died of thyroid cancer, and it is estimated that there may be up to 4,000 excess cancer deaths among the approximately 600,000 most highly exposed people. Of the 100 million curies (4 exabecquerels) of radioactive material, the short lived radioactive isotopes such as I Chernobyl released were initially the most dangerous. Due to their short half-lives of 5 and 8 days they have now decayed, leaving the more long-lived Cs (with a half-life of 30.07 years) and Sr (with a half-life of 28.78 years) as main dangers.
Radiation-induced cancer | Accidental
Although relatively little of those products are created as the result of the slow decay of thorium, a proper assessment of the radiological toxicity of Th must include the contribution of its daughters, some of which are dangerous gamma emitters, and which are built up quickly following the initial decay of Th due to the absence of long-lived nuclides along the decay chain. As the dangerous daughters of thorium have much lower melting points than thorium dioxide, they are volatilised every time the mantle is heated for use. In the first hour of use large fractions of the thorium daughters Ra, Ra, Pb, and Bi are released.
Thorium | Radiological
The three diverging jet stream layers conducted radionuclides across the US to Canada, the Gulf of Mexico and the Atlantic Ocean. Some 86 workers at the site were exposed to radioactivity, but according to the Department of Energy none received a dose exceeding site guidelines and, similarly, radiation drifting offsite was not considered to pose a hazard by the DOE. In March 2009, TIME magazine identified the Baneberry Test as one of the world's worst nuclear disasters. Two US Federal court cases resulted from the Baneberry event. Two NTS workers who were exposed to high levels of radiation from Baneberry died in 1974, both from acute myeloid leukemia.
Yucca Flat | Baneberry
This was discovered in the earliest nuclear reactors built by the Manhattan Project for plutonium production. As a result, the designers made provisions in the design to increase the reactor's reactivity (the number of neutrons per fission that go on to fission other atoms of nuclear fuel). Xe reactor poisoning played a major role in the Chernobyl disaster. By a neutron capture, Xe is transformed ("burned") to Xe, which is effectively stable and does not significantly absorb neutrons.
Iodine pit | Fission products decay and burnup
Caesium-137, with a half-life of 30.17 years, is one of the two principal medium-lived fission products, along with Sr, which are responsible for most of the radioactivity of spent nuclear fuel after several years of cooling, up to several hundred years after use. It constitutes most of the radioactivity still left from the Chernobyl accident and is a major health concern for decontaminating land near the Fukushima nuclear power plant. Cs beta decays to barium-137m (a short-lived nuclear isomer) then to nonradioactive barium-137, and is also a strong emitter of gamma radiation. Cs has a very low rate of neutron capture and cannot be feasibly disposed of in this way, but must be allowed to decay.
Isotopes of caesium | Caesium-137
Prussian blue helps the body excrete caesium-137. Strontium-90 behaves like calcium, and tends to deposit in bone and blood-forming tissue (bone marrow). 20–30% of ingested Sr-90 is absorbed and deposited in the bone. Internal exposure to Sr-90 is linked to bone cancer, cancer of the soft tissue near the bone, and leukemia. Risk of cancer increases with increased exposure to Sr-90.
Radiation effects from the Fukushima Daiichi nuclear disaster | Isotopes of concern
Radiation poisoning, also called "radiation sickness" or a "creeping dose", is a form of damage to organ tissue due to excessive exposure to ionizing radiation. The term is generally used to refer to acute problems caused by a large dosage of radiation in a short period, though this also has occurred with long-term exposure to low-level radiation. Many of the symptoms of radiation poisoning occur as ionizing radiation interferes with cell division. There are numerous lethal radiation syndromes, including prodromal syndrome, bone marrow death, central nervous system death and gastrointestinal death.
Effects of nuclear explosions on human health | Radiation poisoning
A Veterinary Corps officer, Captain J. Stevenson, had already been assigned to look after the guard dogs. Laboratory facilities for medical research were limited, but some research was conducted into the effects of radiation, and the absorption and toxic effects of metals, particularly plutonium and beryllium, mainly as a result of accidents. The Health Group began conducting urine tests of laboratory workers in early 1945, and many of these revealed dangerous levels of plutonium. Work on the Water Boiler also occasionally exposed workers to dangerous fission products. There were 24 fatal accidents at Los Alamos between its opening in 1943 and September 1946.
Project Y | Health and safety
Some aging nuclear facilities were not originally intended to operate as long as they have, and the consequences of their waste procedures were not well understood when they were built. One example of this is how the radionuclide tritium is sometimes released into the surrounding environment as a result of nuclear reprocessing, as this was not a foreseen complication in the original waste management orders of operations. It is difficult to diverge from these procedures once a reactor has already been put to use, since any change either risks releasing even more radioactive material or jeopardizes the safety of the individuals working on the disposal.
Radioecology | Radioecological Threats
One tonne of waste, as described above, has measurable radioactivity of approximately 600 TBq equal to the natural radioactivity in one km of the Earth's crust, which if buried, would add only 25 parts per trillion to the total radioactivity. The difference between short-lived high-level nuclear waste and long-lived low-level waste can be illustrated by the following example. As stated above, one mole of both I and I release 3x10 decays in a period equal to one half-life. I decays with the release of 970 keV whilst I decays with the release of 194 keV of energy. 131gm of I would therefore release 45 gigajoules over eight days beginning at an initial rate of 600 EBq releasing 90 kilowatts with the last radioactive decay occurring inside two years.
Nuclear safety and security | Hazards of nuclear material
Caesium-137 reacts with water, producing a water-soluble compound (caesium hydroxide). The biological behaviour of caesium is similar to that of potassium and rubidium. After entering the body, caesium gets more or less uniformly distributed throughout the body, with the highest concentrations in soft tissue. The biological half-life of caesium is about 70 days. A 1961 experiment showed that mice dosed with 21.5 μCi/g had a 50% fatality within 30 days (implying an LD of 245 µg/kg). A similar experiment in 1972 showed that when dogs are subjected to a whole body burden of 3800 μCi/kg (140 MBq/kg, or approximately 44 μg/kg) of caesium-137 (and 950 to 1400 rads), they die within 33 days, while animals with half of that burden all survived for a year.
Caesium-137 | Health risk of radioactive caesium
Studies carried out by the Committee on Medical Aspects of Radiation in the Environment (COMARE) in 2003 reported no evidence of raised childhood cancer in general around nuclear power plants, but did report an excess of leukaemia (cancer of the blood or bone) and non-Hodgkin's lymphoma (NHL, a blood cancer) near two other nuclear installations including Sellafield, the Atomic Weapons Establishment Burghfield and UKAEA Dounreay. COMARE's conclusion was that "the excesses around Sellafield and Dounreay are unlikely to be due to chance, although there is not at present a convincing explanation for them". In earlier reports COMARE had suggested that ""a mechanism involving infection may be a significant factor." The clusters have disappeared in the early 1990s.
Sellafield | Health studies in Cumbria and Seascale
However, this fission product yield is reduced in most reactors because the predecessor, Xe, is a potent neutron poison and frequently transmutes to stable Xe before it can decay to Cs.
Caesium | Isotopes
Radioactive contamination, also called radiological contamination, is the deposition of, or presence of radioactive substances on surfaces or within solids, liquids or gases (including the human body), where their presence is unintended or undesirable (from the International Atomic Energy Agency (IAEA) definition). Such contamination presents a hazard because of the radioactive decay of the contaminants, which produces such harmful effects as ionizing radiation (namely α, β, and γ rays) and free neutrons. The degree of hazard is determined by the concentration of the contaminants, the energy of the radiation being emitted, the type of radiation, and the proximity of the contamination to organs of the body.
Radioactive contamination | Introduction
The Nuclear Regulatory Commission's estimate of the risk each year of an earthquake intense enough to cause core damage to the reactor at Beaver Valley was Reactor 1: 1 in 20,833; Reactor 2: 1 in 45,455, according to an NRC study published in August 2010.
Beaver Valley Nuclear Power Station | Seismic risk
Another health hazard is its decay product, the radioactive gas radon, which constitutes a significant risk even at extremely low concentrations when inhaled. Radium's long half-life of 1600 years means that surfaces coated with radium paint, such as watch faces and hands, remain a health hazard long after their useful life is over. There are still millions of luminous radium clock, watch, and compass faces and aircraft instrument dials owned by the public. The case of the "Radium Girls", workers in watch factories in the early 1920s who painted watch faces with radium paint and later contracted fatal cancer through ingesting radium when they pointed their brushes with their lips, increased public awareness of the hazards of radioluminescent materials, and radioactivity in general.
Radioluminescence | Radium
Such was the outcome of the 1986 Chernobyl nuclear disaster in Ukraine. A comprehensive 2005 study concluded that "the mental health impact of Chernobyl is the largest public health problem unleashed by the accident to date". Frank N. von Hippel, a U.S. scientist, commented on 2011 Fukushima nuclear disaster, saying that "fear of ionizing radiation could have long-term psychological effects on a large portion of the population in the contaminated areas". Evacuation and long-term displacement of affected populations create problems for many people, especially the elderly and hospital patients. Such great psychological danger does not accompany other materials that put people at risk of cancer and other deadly illness.
Radioactive contamination | Social and psychological effects
Today, Ra is considered to be the most toxic of the quantity radioelements, and it must be handled in tight glove boxes with significant airstream circulation that is then treated to avoid escape of its daughter Rn to the environment. Old ampoules containing radium solutions must be opened with care because radiolytic decomposition of water can produce an overpressure of hydrogen and oxygen gas. The world's largest concentration of Ra is stored within the Interim Waste Containment Structure, approximately north of Niagara Falls, New York.
Radium | Hazards
The health and environmental hazards of radioactive thorium consists of effects in plant growth and dangers to humans and animals that involves cancers and disorders when exposed to thorium for periods of time.
Maywood Superfund site | Health and environmental hazards
In nuclear science, the decay chain refers to a series of radioactive decays of different radioactive decay products as a sequential series of transformations. It is also known as a "radioactive cascade". Most radioisotopes do not decay directly to a stable state, but rather undergo a series of decays until eventually a stable isotope is reached. Decay stages are referred to by their relationship to previous or subsequent stages. A "parent isotope" is one that undergoes decay to form a "daughter isotope". One example of this is uranium (atomic number 92) decaying into thorium (atomic number 90). The daughter isotope may be stable or it may decay to form a daughter isotope of its own.
Decay chain | Introduction
This is partly because the timeframes in question when dealing with radioactive waste range from 10,000 to millions of years, according to studies based on the effect of estimated radiation doses. Since the fraction of a radioisotope's atoms decaying per unit of time is inversely proportional to its half-life, the relative radioactivity of a quantity of buried human radioactive waste would diminish over time compared to natural radioisotopes (such as the decay chain of 120 trillion tons of thorium and 40 trillion tons of uranium which are at relatively trace concentrations of parts per million each over the crust's 3 ton mass).
Nuclear power debate | High-level radioactive waste
The doctors selected patients likely to die in the near future. Despite the doctors' prognoses, several lived for decades after. Ebb Cade was an unwilling participant in medical experiments that involved injection of 4.7 micrograms of Plutonium on 10 April 1945 at Oak Ridge, Tennessee. This experiment was under the supervision of Harold Hodge.
Advisory Committee on Human Radiation Experiments | Background
The Chernobyl release was characterised by the physical and chemical properties of the radio-isotopes in the core. Particularly dangerous were the highly radioactive fission products, those with high nuclear decay rates that accumulate in the food chain, such as some of the isotopes of iodine, caesium and strontium. Iodine-131 was and caesium-137 remains the two most responsible for the radiation exposure received by the general population. Detailed reports on the release of radioisotopes from the site were published in 1989 and 1995, with the latter report updated in 2002. At different times after the accident, different isotopes were responsible for the majority of the external dose.
Chernobyl disaster | Relative isotopic abundances
Thomson deliberately exposed a finger to an X-ray tube over a period of time and suffered pain, swelling, and blistering. Other effects, including ultraviolet rays and ozone, were sometimes blamed for the damage, and many physicians still claimed that there were no effects from X-ray exposure at all. Despite this, there were some early systematic hazard investigations, and as early as 1902 William Herbert Rollins wrote almost despairingly that his warnings about the dangers involved in the careless use of X-rays were not being heeded, either by industry or by his colleagues. By this time, Rollins had proved that X-rays could kill experimental animals, could cause a pregnant guinea pig to abort, and that they could kill a foetus.
Radioactive decay | X-rays
Alpha particles are identical with helium-4 nuclei. Alpha particles travel short distances in air, of only 2–3 cm, and cannot penetrate through a dead layer of skin on the human body. However, some radium alpha particle emitters are "bone seekers" due to radium possessing a high affinity for chloride ions. In the case that radium atoms are not expelled from the body, they concentrate in areas where chloride ions are prevalent, such as bone tissue. The half-life for radium 226 is approximately 1,620 years, and will remain in the body for the lifetime of the human — a significant length of time to cause damage.
Naturally occurring radioactive material | Hazards
However, the biological effects of radiation due to radioactive substances were less easy to gauge. This gave the opportunity for many physicians and corporations to market radioactive substances as patent medicines. Examples were radium enema treatments, and radium-containing waters to be drunk as tonics. Marie Curie protested against this sort of treatment, warning that the effects of radiation on the human body were not well understood. Curie later died from aplastic anaemia, likely caused by exposure to ionizing radiation. By the 1930s, after a number of cases of bone necrosis and death of radium treatment enthusiasts, radium-containing medicinal products had been largely removed from the market (radioactive quackery).
Radioactive decay | Radioactive substances
Natural thorium decays very slowly compared to many other radioactive materials, and the emitted alpha radiation cannot penetrate human skin. As a result, handling small amounts of thorium, such as those in gas mantles, is considered safe, although the use of such items may pose some risks. Exposure to an aerosol of thorium, such as contaminated dust, can lead to increased risk of cancers of the lung, pancreas, and blood, as lungs and other internal organs can be penetrated by alpha radiation. Internal exposure to thorium leads to increased risk of liver diseases. The decay products of Th include more dangerous radionuclides such as radium and radon.
Thorium | Radiological
Although people in the incident's worst affected areas have a slightly higher risk of developing certain cancers such as leukemia, solid cancers, thyroid cancer, and breast cancer, very few cancers would be expected as a result of accumulated radiation exposures. Estimated effective doses outside Japan are considered to be below (or far below) the levels regarded as very small by the international radiological protection community. In 2013, the World Health Organization reported that area residents who were evacuated were exposed to so little radiation that radiation-induced health effects were likely to be below detectable levels. The health risks were calculated by applying conservative assumptions, including the conservative linear no-threshold model of radiation exposure, a model that assumes even the smallest amount of radiation exposure will cause a negative health effect.
Fukushima Daiichi nuclear disaster | Risks from ionizing radiation
An example of a short-lived fission product is iodine-131, this can also be formed as an activation product by the neutron activation of tellurium. In both bomb fallout and a release from a power reactor accident, the short-lived isotopes cause the dose rate on day one to be much higher than that which will be experienced at the same site many days later. This holds true even if no attempts at decontamination are made. In the graphs below, the total gamma dose rate and the share of the dose due to each main isotope released by the Chernobyl accident are shown.
Environmental radioactivity | Short lived
The danger of radiation from fallout also decreases rapidly with time due in large part to the exponential decay of the individual radionuclides. A book by Cresson H. Kearny presents data showing that for the first few days after the explosion, the radiation dose rate is reduced by a factor of ten for every seven-fold increase in the number of hours since the explosion. He presents data showing that "it takes about seven times as long for the dose rate to decay from 1000 roentgens per hour (1000 R/hr) to 10 R/hr (48 hours) as to decay from 1000 R/hr to 100 R/hr (7 hours)." This is a fairly rough rule of thumb based on observed data, not a precise relation.
Nuclear fallout | The Seven Ten Rule
Lastly the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) consider that the exposure of the lungs to 1 Bq of Rn (in equilibrium with its decay products) for one year will cause a dose of 61 μSv.
Radium and radon in the environment | In mines
A variety of radionuclides occur naturally in the environment. Elements like uranium and thorium, and their decay products, are present in rock and soil. Potassium-40, a primordial nuclide, makes up a small percentage of all potassium and is present in the human body. Other nuclides, like carbon-14, which is present in all living organisms, are continuously created by cosmic rays. These levels of radioactivity pose little danger but can confuse measurement. A particular problem is encountered with naturally generated radon gas which can affect instruments which are set to detect contamination close to normal background levels and can cause false alarms.
Radioactive contamination | Naturally occurring radioactivity
In adult mammals cell division is slow, except in hair follicles, skin, bone marrow and the gastrointestinal tract, which is why vomiting and hair loss are common symptoms of acute radiation sickness.
Chernobyl disaster | Effects of main harmful radionuclides
Hydrogen and other gases evolved by high-temperature reaction of metals with cooling water, and 3–4 minutes later oxyhydrogen exploded in the calandria. During the incident, some gaseous fission products were vented to the atmosphere, and heavy water in the calandria was contaminated with the cooling water and the fission products. To remove decay heat, the water cooling system was kept operating, leaking contaminated coolant to the floor. About of radioactive materials, contained in about a million gallons (about 4000 m) of water, were dumped to the basement of the reactor building during the next few days.
NRX | Accident
With the completion of the NRX reactor in 1947, AECL's Chalk River Laboratories possessed the world's most powerful research reactor. While the large neutron fluxes available in the reactor led to advances in such fields as condensed matter physics and neutron spectroscopy, many experiments were carried out involving the production of new isotopes. The field of nuclear medicine developed when it was realized that some of these artificially created isotopes could be used to diagnose and treat many diseases, especially cancers. Pioneering medical work done in the late 1940s and early 1950s established cobalt-60 as a useful isotope, as the relatively high-energy gamma rays produced when it undergoes beta decay are able to penetrate the skin of the patient, and deliver a greater portion of the dose directly to the tumor.
Multipurpose Applied Physics Lattice Experiment | Background
Major nuclear reactor accidents include Three Mile Island accident (1979), Chernobyl disaster (1986), and Fukushima (2011). A report in "Lancet" says that the effects of these accidents on individuals and societies are diverse and enduring. Relatively few immediate deaths have occurred, but nuclear-related fatalities are mostly in the hazardous uranium mining industry, which supplies fuel to nuclear reactors. There are also physical health problems directly attributable to radiation exposure, as well as psychological and social effects. The Fukushima accident forced more than 80,000 residents to evacuate from neighborhoods around the crippled nuclear plant. Evacuation and long-term displacement create severe health-care problems for the most vulnerable people, such as hospital inpatients and elderly people.
Nuclear renaissance | Accidents and safety
Intake of radioactive materials into the body tends to increase the risk of cancer, and possibly other stochastic effects. The International Commission on Radiological Protection has proposed a model whereby the incidence of cancers increases linearly with effective dose at a rate of 5.5% per sievert. This model is widely accepted for external radiation, but its application to internal contamination has been disputed. This model fails to account for the low rates of cancer in early workers at Los Alamos National Laboratory who were exposed to plutonium dust, and the high rates of thyroid cancer in children following the Chernobyl accident .
Committed dose | Health effects
One of the striking things about places heavily contaminated by radioactive nuclides is the richness of their wildlife. This is true of the land around Chernobyl, the bomb test sites of the Pacific, and areas near the United States' Savannah River nuclear weapons plant of the Second World War. Wild plants and animals do not perceive radiation as dangerous, and any slight reduction it may cause in their lifespans is far less a hazard than is the presence of people and their pets... I find it sad, but all too human, that there are vast bureaucracies concerned about nuclear waste, huge organisations devoted to decommissioning power stations, but nothing comparable to deal with that truly malign waste, carbon dioxide.
James Lovelock | Nuclear power
The energy and the type of the ionizing radiation emitted by a radioactive substance are also important factors in determining its threat to humans. The chemical properties of the radioactive element will determine how mobile the substance is and how likely it is to spread into the environment and contaminate humans. This is further complicated by the fact that many radioisotopes do not decay immediately to a stable state but rather to radioactive decay products within a decay chain before ultimately reaching a stable state.
Radioactive waste | Physics
There are ongoing concerns around deterioration of the nuclear waste site on the Enewetak Atoll of the Marshall Islands and a potential radioactive spill. Scavenging of abandoned radioactive material has been the cause of several other cases of radiation exposure, mostly in developing nations, which may have less regulation of dangerous substances (and sometimes less general education about radioactivity and its hazards) and a market for scavenged goods and scrap metal. The scavengers and those who buy the material are almost always unaware that the material is radioactive and it is selected for its aesthetics or scrap value. Irresponsibility on the part of the radioactive material's owners, usually a hospital, university or military, and the absence of regulation concerning radioactive waste, or a lack of enforcement of such regulations, have been significant factors in radiation exposures.
Radioactive waste | Accidents
The daughter nuclide of a decay event may also be unstable (radioactive). In this case, it too will decay, producing radiation. The resulting second daughter nuclide may also be radioactive. This can lead to a sequence of several decay events called a "decay chain" (see this article for specific details of important natural decay chains). Eventually, a stable nuclide is produced. Any decay daughters that are the result of an alpha decay will also result in helium atoms being created. An example is the natural decay chain of U: Some radionuclides may have several different paths of decay. For example, approximately 36% of bismuth-212 decays, through alpha-emission, to thallium-208 while approximately 64% of bismuth-212 decays, through beta-emission, to polonium-212.
Radioactive decay | Decay chains and multiple modes
Gastrointestinal death is caused by a dose of radiation between 10 and 50 Gray. Whole body doses cause damage to epithelial cells lining the gastrointestinal tract and this combined with the bone marrow damage is fatal. All symptoms become increasingly severe, causing exhaustion and emaciation in a few days and death within 7–14 days from loss of water and electrolytes. The symptoms of gastrointestinal death are:
Effects of nuclear explosions on human health | Gastrointestinal death
According to the IAEA, in 1960, a person ingested 74 MBq of radium (assumed to be Ra) and this person died four years later. Harold McCluskey survived 11 years (eventually dying from cardio respiratory failure) after an intake of at least 37 MBq of Am (He was exposed in 1976). It is estimated that he suffered doses of 18 Gy to his bone mass, 520 Gy to the bone surface, 8 Gy to the liver and 1.6 Gy to the lungs; it is also claimed that a post mortem examination revealed no signs of cancer in his body. The October 1983 issue of the journal "Health Physics" was dedicated to McCluskey, and subsequent papers about him appeared in the September 1995 issue.
Poisoning of Alexander Litvinenko | Deaths from ingesting radioactive materials
The buildup of short-lived fission products acting as nuclear poisons is called reactor poisoning, or xenon poisoning. Buildup of stable or long-lived neutron poisons is called reactor slagging.
Iodine pit | Introduction
The people of the islands would consume meat or products from animals that had been irradiated, therefore irradiating the consumer. Food shipped into the islands was also affected by contamination through contaminated cooking utensils. Many dairy products, such as milk and yogurt, were contaminated as a result of radionuclides landing on pastures. Iodine-131, a highly radioactive isotope, was ingested or inhaled by many through various forms. The iodine-131 consumed would become concentrated in one's thyroid. On the Marshall Islands, the detonation of Castle Bravo was the cause of most of the radiation exposure to the surrounding populations. The fallout levels attributed to the Castle Bravo test are the highest in history.
Nuclear testing at Bikini Atoll | Health impacts
The radioactivity in the fission product mixture is initially mostly caused by short lived isotopes such as Iodine-131 and Ba; after about four months Ce, Zr/Nb and Sr take the largest share, while after about two or three years the largest share is taken by Ce/Pr, Ru/Rh and Pm. Later Sr and Cs are the main radioisotopes, being succeeded by Tc. In the case of a release of radioactivity from a power reactor or used fuel, only some elements are released; as a result, the isotopic signature of the radioactivity is very different from an open air nuclear detonation, where all the fission products are dispersed.
Nuclear fission product | Decay
Apart from the 57 direct deaths in the accident itself, UNSCEAR predicted in 2005 that up to 4,000 additional cancer deaths related to the accident would appear "among the 600 000 persons receiving more significant exposures (liquidators working in 1986–87, evacuees, and residents of the most contaminated areas)". According to BBC, "It is conclusive that around 5,000 cases of thyroid cancer — most of which were treated and cured — were caused by the contamination. Many suspect that the radiation has caused or will cause other cancers, but the evidence is patchy. Amid reports of other health problems — including birth defects — it still is not clear if any can be attributed to radiation".
Nuclear power debate | Chernobyl steam explosion
It is important to be clear that the contamination gives rise to the radiation hazard, and the terms "radiation" and "contamination" are not interchangeable. The sources of radioactive pollution can be classified into two groups: natural and man made. Following an atmospheric nuclear weapon discharge or a nuclear reactor containment breach, the air, soil, people, plants, and animals in the vicinity will become contaminated by nuclear fuel and fission products. A spilled vial of radioactive material like uranyl nitrate may contaminate the floor and any rags used to wipe up the spill. Cases of widespread radioactive contamination include the Bikini Atoll, the Rocky Flats Plant in Colorado, the Fukushima Daiichi nuclear disaster, the Chernobyl disaster, and the area around the Mayak facility in Russia.
Radioactive contamination | Introduction
In 2013, two years after the incident, the World Health Organization indicated that the residents of the area who were evacuated were exposed to so little radiation that radiation induced health impacts are likely to be below detectable levels. The health risks in the WHO assessment attributable to the Fukushima radioactivity release were calculated by largely applying the conservative Linear no-threshold model of radiation exposure, a model that assumes even the smallest amount of radiation exposure will cause a negative health effect. The WHO calculations using this model determined that the most at risk group, infants, who were in the most affected area, would experience an absolute increase in the risk of cancer (of all types) during their lifetime, of approximately 1% due to the accident.
Fukushima Daiichi nuclear disaster casualties | WHO Report
Following the test, the United States Department of Energy estimated that 253 inhabitants of the Marshall Islands were impacted by the radioactive fallout. This single test exposed the surrounding populations to varying levels of radiation. The fallout levels attributed to the Castle Bravo test are the highest in history. Populations neighboring the test site were exposed to high levels of radiation resulting in mild radiation sickness of many (nausea, vomiting, diarrhea). Several weeks later, many people began suffering from alopecia (hair loss) and skin lesions as well. The exposure to fallout has been linked to increase the likelihood of several types of cancer such as leukemia and thyroid cancer.
Castle Bravo | Health impacts
In a 2013 report, the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) stated the overall health risks from the Fukushima disaster to be far lower than those of Chernobyl. There have been no observed or expected deterministic effects. In pregnancies, there has been no expected increase in spontaneous abortions, miscarriages, perinatal mortality, birth defects, or cognitive impairment. Finally, there was no expected discernible increase in heritable disease or discernible radiation-related increases in any cancers, with the possible exception of thyroid cancer. However, the high detection rates of thyroid nodules, cysts, and cancer may be a consequence of intensive screening.
List of nuclear and radiation accidents by death toll | Fukushima disaster
Delayed nuclear radiation is a form of nuclear decay. When an isotope decays into a very short-lived isotope and then decays again to a relatively long-lived isotope, the products of the second decay are delayed. The short-lived isotope is usually a meta-stable nuclear isomer. For example, gallium-73 decays via beta decay into germanium-73m2, which is short-lived (499ms). The germanium isotope emits two weak gamma rays and a conversion electron. Because the middle isotope is so short-lived, the gamma rays are considered part of the gallium decay. Therefore, the above equations are combined.
Delayed nuclear radiation | Introduction
Extended periods of exposure to Rn and its progeny ultimately induce lung cancer. Alternatively, radon may enter the body through contaminated drinking water or through the decay of ingested radium – making radon diffusion one of the greatest dangers of radium. Thus, Rn is a carcinogen; in fact, it is the second leading cause of lung cancer in the United States after cigarette smoking, with over 20,000 deaths per year attributed to radon-induced lung cancer.
Radon-222 | Occurrence and hazards
Exposure to radioactive waste may cause health impacts due to ionizing radiation exposure. In humans, a dose of 1 sievert carries a 5.5% risk of developing cancer, and regulatory agencies assume the risk is linearly proportional to dose even for low doses. Ionizing radiation can cause deletions in chromosomes. If a developing organism such as a fetus is irradiated, it is possible a birth defect may be induced, but it is unlikely this defect will be in a gamete or a gamete-forming cell. The incidence of radiation-induced mutations in humans is small, as in most mammals, because of natural cellular-repair mechanisms, many just now coming to light.
Radioactive waste | Pharmacokinetics
The consequences of low-level radiation are often more psychological than radiological. Because damage from very-low-level radiation cannot be detected, people exposed to it are left in anguished uncertainty about what will happen to them. Many believe they have been fundamentally contaminated for life and may refuse to have children for fear of birth defects. They may be shunned by others in their community who fear a sort of mysterious contagion. Forced evacuation from a radiation or nuclear accident may lead to social isolation, anxiety, depression, psychosomatic medical problems, reckless behavior, even suicide. Such was the outcome of the 1986 Chernobyl nuclear disaster in the Ukraine.
Linear no-threshold model | Mental health effects
For fission of uranium-235, the predominant radioactive fission products include isotopes of iodine, caesium, strontium, xenon and barium. The threat becomes smaller with the passage of time. Locations where radiation fields once posed immediate mortal threats, such as much of the Chernobyl Nuclear Power Plant on day one of the accident and the ground zero sites of U.S. atomic bombings in Japan (6 hours after detonation) are now relatively safe because the radioactivity has decayed to a low level. Many of the fission products decay through very short-lived isotopes to form stable isotopes, but a considerable number of the radioisotopes have half-lives longer than a day.
Nuclear fission product | Decay
Strontium-90 is not quite as likely as caesium-137 to be released as a part of a nuclear reactor accident because it is much less volatile, but is probably the most dangerous component of the radioactive fallout from a nuclear weapon. A study of hundreds of thousands of deciduous teeth, collected by Dr. Louise Reiss and her colleagues as part of the Baby Tooth Survey, found a large increase in Sr levels through the 1950s and early 1960s. The study's final results showed that children born in St. Louis, Missouri, in 1963 had levels of Sr in their deciduous teeth that was 50 times higher than that found in children born in 1950, before the advent of large-scale atomic testing.
Strontium-90 | Sr contamination in the environment