Therefore, health effects of alpha-ray exposures appear only when alpha-emitting materials are ingested i. Beta rays are produced following spontaneous decay of certain radioactive materials, such as tritium an isotope of hydrogen , carbon, phosphorus, and strontium Depending on its energy i.
As with alpha rays, the major concern for health effects is after their ingestion i. An electromagnetic wave, a gamma ray is similar to ordinary visible light but differs in energy or wavelength.
Sunlight consists of a mixture of electromagnetic rays of various wavelengths, from the longest, infrared, through red, orange, yellow, green, blue, indigo, and violet, to the shortest in wavelength, ultraviolet.
Gamma rays are produced following spontaneous decay of radioactive materials, such as cobalt and cesium A cobalt gamma ray can penetrate deeply into the human body, so it has been widely used for cancer radiotherapy. X rays have the same characteristics as gamma rays, although they are produced differently.
When high-speed electrons hit metals, electrons are stopped and release energy in the form of an electromagnetic wave. This was first observed by Wilhelm Roentgen in , who considered it a mysterious ray, and thus called it an X ray. It can cause damage by breaking chemical bonds.
Types of ionising radiation include: Alpha particles — two protons and two neutrons bound together like a helium nucleus — are large particles that can do lots of damage, but only over short distances. Beta particles — are electrons, which can travel longer distances in air and tissue than alpha particles.
Neutron radiation — consisting of free neutrons which are released during fission but not usually through radioactive decay. Gamma or x-rays , which are electromagnetic radiation similar to light, but with much more energy. Find out more about radiation in our Bernie's Basics: It's radioactive man. But it only lasts as long as you're near the source, once you move away, you are not being irradiated any more.
This usually causes the cell to die. DNA can be repaired, but if the repair is incorrect, it could cause mutation which could lead to cancer later on". As the radiation dose gets higher many sieverts this can kill you very quickly, in a matter of hours if the dose is high enough.
Plutonium and uranium produce a range of radioactive fission products including variations of iodine, caesium, strontium and noble gases such as argon and xenon. Some radioactive substances can remain dangerous in the environment longer than others. Just how long is indicated by the isotope's 'half-life' — the time it takes for half of a radioactive isotope to decay away.
The risk of radiation poisoning following the Fukushima incident will be related to the level of exposure people face, says Crossley. The Japanese government has confirmed three plutonium isotopes Pu, Pu and Pu, have been detected in soil in the exclusion zone near the Fukushima facility. As well as being a by-product of nuclear reactions, it's also part of the fuel mix used at the power station's number three reactor. Plutonium releases mostly alpha radiation, and is a serious health hazard if ingested or inhaled in significant amounts, remaining in the lungs, or absorbed into the blood stream where it moves into bones, liver or other organs exposing surrounding tissue to radiation for decades.
There are also reports of strontium and strontium being discovered in the environment near the plant. These have half lives of 50 days and 30 years, respectively. Strontium can be inhaled, but is usually swallowed in food or water. It's deposited on bone issue and is linked to bone cancer, cancer of soft tissue near the bone and leukemia.
But Crossley says the risk of radioactive strontium causing problems for people is again directly proportional to the amount consumed. High levels of radioactive iodine and caesium and caesium have also been detected in the environment around the plant affecting local produce. Iodine binds to tissue in the thyroid gland, emitting beta particles and can potentially cause DNA mutation and cell death in high doses. This means that any seafood from the area will need to face ongoing screening until contamination levels fall below legally safe amounts, he says.
Caesium is a persistent problem if the soil is heavily contaminated like it was around Chernobyl, says Crossley. You could also inhale it in dust particles," he says. Once ingested, caesium gets distributed fairly uniformly throughout the body with slightly higher concentrations in muscle and lower levels in bone and fat. In the meantime, food products will be screened and not allowed to be sold if they are above legal limits which are set very low. Are there any health benefits of ionising radiation?
Paradoxically, many radioactive substances are also often used in nuclear medicine to diagnose and treat conditions such as thyroid cancer iodine bone cancer strontium and samarium bone scans techniciumm PET scans fluorine knee problems and liver cancer yttrium
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