Issue: Protecting the environment from ionising radiation.
Forum: Environment Commission
Student Officer: WeronikaChilewska
Position: Deputy President
Introduction
Ionising radiation has always been a part of the human environment. Along with natural radioactive sources present in the Earth's crust and cosmic radiation, man-made sources also contribute to our continuous exposure to ionizing radiation.
Environmental radioactive pollution has resulted from past nuclear weapons testing, nuclear waste disposal, accidents at nuclear power plants, as well as from transportation, storage, loss, and misuse of radioactive sources. While there are risks associated with exposure to radiation benefits of nuclear applications in medicine industry and science are well established.
Definition of Key Terms
Ionising radiation
Ionising radiation is radiation that carries enough energy to free electrons from atoms or molecules, thereby ionizing them. Ionizing radiation is made up of energetic subatomic particles, ions or atoms moving at relativistic speeds, and electromagnetic waves on the high-energy end of the electromagnetic spectrum
Radiation protection
Radiation protection, sometimes known as radiological protection, is the science and practice of protecting people and the environment from the harmful effects of ionizing radiation.
Major parties involved
International Atomic Energy Agency
The IAEA is widely known as the world's "Atoms for Peace" organization within the United Nations family. Set up in 1957 as the world's centre for cooperation in the nuclear field, the Agency works with its Member States and multiple partners worldwide to promote the safe, secure and peaceful use of nuclear technologies.
TheInternational Commission on Radiological Protection
The work of the International Commission on Radiological Protection (ICRP) helps to prevent cancer and other diseases and effects associated with exposure to ionising radiation, and to protect the environment.
Since 1928, ICRP has developed, maintained, and elaborated the International System of Radiological Protection used world-wide as the common basis for radiological protection standards, legislation, guidelines, programmes, and practice.
International Commission on Radiation Units and Measurements
The International Commission on Radiation Units and Measurements (ICRU) is a standardization body set up in 1925 by the International Congress of Radiology, originally as the X-Ray Unit Committee until 1950. Its objective "is to develop concepts, definitions and recommendations for the use of quantities and their units for ionizing radiation and its interaction with matter, in particular with respect to the biological effects induced by radiation".[1]
The ICRU is a sister organisation to the International Commission on Radiological Protection (ICRP). In general terms the ICRU defines the units, and the ICRP recommends how they are used for radiation protection.
Important Documents
Atomic Energy Agency’s Fundamental SafetyPrinciples
This publication states the fundamental safety objective and ten associated safety principles, and briefly describes their intent and purpose. The fundamental safety objective — to protect people and the environment from harmful effects of ionizing radiation — applies to all circumstances that give rise to radiation risks. The safety principles are applicable, as relevant, throughout the entire lifetime of all facilities and activities, existing and new, utilized for peaceful purposes, and to protective actions to reduce existing radiation risks. They provide the basis for requirements and measures for the protection of people and the environment against radiation risks and for the safety of facilities and activities that give rise to those risks. These include, in particular, nuclear installations and uses of radiation and radioactive sources, the transport of radioactive material and the management of radioactive waste
The Recommendations of the International Commission on Radiological Protection
These revised Recommendations for a System of Radiological Protection formally replace the Commissions previous, 1990, Recommendations; and update, consolidate, and develop the additional guidance on the control of exposure from radiation sources issued since 1990.
Thus, the present Recommendations update the radiation and tissue weighting factors in the quantities equivalent and effective dose and update the radiation detriment, based on the latest available scientific information of the biology and physics of radiation exposure. They maintain the Commissions three fundamental principles of radiological protection, namely justification, optimisation, and the application of dose limits, clarifying how they apply to radiation sources delivering exposure and to individuals receiving exposure.
Categories of radiationexposure
Because of the variety and complexity of situations that may give rise to radiation exposureand the need to develop an effective system of radiation protection, exposures to radiationare divided into four categories of exposure: occupational, medical, public and environmental.
- Occupational exposures are incurred at work and principally as a result of working directlywith radiation. Exposure to radiation from natural sources is generally excluded fromoccupational exposure, except when the exposure is a direct consequence of a plannedexposure situation.
- Medical exposure is the exposure incurred by patients as part of their medical or dentaldiagnosis or treatment. It also includes doses received by volunteers in a program ofbiomedical research involving their exposure, and doses received by persons (other than thoseoccupationally exposed) who are knowingly exposed while voluntarily helping in the supportand comfort of patients.
- Public exposure covers all exposures of people other than occupational exposure and medicalexposure. Exposures of the embryo or foetus of pregnant workers are considered to be publicexposures.
- Environmental exposure is the exposure of wildlife to all additional radiation sources resultingfrom human activities. Wildlife may require protection in order to maintain biological diversity,conservation of species, or the health and status of natural habitats, communities andecosystems, or anything that may be otherwise required from a conservation point of view inaccordance with relevant legislation.
Environmental and humanhealtheffects of ionising radiation
Stochastic Health Effects
Stochastic effects are associated with long-term, low-level (chronic) exposure to radiation. Increased levels of exposure make these health effects more likely to occur, but do not influence the type or severity of the effect.
Cancer is considered the primary health effect from radiation exposure. Cancer is the uncontrolled growth of cells. Ordinarily, natural processes control the rate at which cells grow and replace themselves. They also control the body's processes for repairing or replacing damaged tissue. Damage occurring at the cellular or molecular level, can disrupt the control processes, permitting the uncontrolled growth of cells cancer This is why ionizing radiation's ability to break chemical bonds in atoms and molecules makes it such a potent carcinogen.
Radiation can cause changes in DNA, the "blueprints", that ensure cell repair and replacement produces a perfect copy of the original cell - mutations. Sometimes the body fails to repair these mutations or even creates mutations during repair. The mutations can be teratogenic or genetic. Teratogenic mutations are caused by exposure of the fetus in the uterus and affect only the individual who was exposed. Genetic mutations are passed on to offspring.
Non-Stochastic Health Effects
Non-stochastic effects appear in cases of exposure to high levels of radiation, and become more severe as the exposure increases. Short-term, high-level exposure is referred to as 'acute' exposure.
Many non-cancerous health effects of radiation are non-stochastic. Unlike cancer, health effects from 'acute' exposure to radiation usually appear quickly. Acute health effects include burns and radiation sickness. Radiation sickness is also called 'radiation poisoning.' It can cause premature aging or even death. If the dose is fatal, death usually occurs within two months. The symptoms of radiation sickness include: nausea, weakness, hair loss, skin burns or diminished organ function.
Medical patients receiving radiation treatments often experience acute effects, because they are receiving relatively high "bursts" of radiation during treatment.
Other long-term health effects
Other than cancer, the most prominent long-term health effects are teratogenic and genetic mutations.
Teratogenic mutations result from the exposure of fetuses (unborn children) to radiation. They can include smaller head or brain size, poorly formed eyes, abnormally slow growth, and mental retardation. Studies indicate that fetuses are most sensitive between about eight to fifteen weeks after conception. They remain somewhat less sensitive between six and twenty-five weeks old.The relationship between dose and mental retardation is not known exactly. However, scientists estimate that if 1,000 fetuses that were between eight and fifteen weeks old were exposed to one rem, four fetuses would become mentally retarded. If the fetuses were between sixteen and twenty-five weeks old, it is estimated that one of them would be mentally retarded.
Genetic effects are those that can be passed from parent to child. Health physicists estimate that about fifty severe hereditary effects will occur in a group of one million live-born children whose parents were both exposed to one rem. About one hundred twenty severe hereditary effects would occur in all descendants.
Environmental effects
Just as ionising radiation affects humans, it may affect other living organisms. This may lead toeffects in the environment, impacting individuals, populations, species and whole ecosystems.
Such effects, which arise from the biological effects of ionising radiation in wildlife are in these
Environmental effects may include:
• increased morbidity (or reduced fitness) of individuals within populations
• increased mortality
• reduced reproductive success (reduced number of offspring caused by reduced fertility or
other factors)
• subtle effects including mutations and effects on ecosystem functions that are currently
the subject of much research.
UN Involvment
The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) was set up by resolution of the United Nations General Assembly. 21 states are designated to provide scientists to serve as members of the committee which holds formal meetings (sessions) annually and submits a report to the General Assembly. The organisation has no power to set radiation standards nor to make recommendations in regard to nuclear testing. It was established solely to define precisely the present exposure of the population of the world to ionizing radiation.
Possible Solutions
To protect human health and the environment from the harmful effects of ionising radiation the followingchangesshould be made:
• implementing strategies to optimise protection
• preventing accidents and mitigating their effects should they occur
• preventing actions with malicious intent that may cause harm from ionising radiation.
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