In a normal and clean environment a person is constantly under the effect of ionising radiation. The radiation is caused by natural as well as artificial factors, i.e. human activity. The main dose of exposure people are subject to is caused by natural factors.
- Natural sources of radiation include cosmic radiation, gamma radiation prevailing at ground level, decay products of radon in the air and various radionuclides found naturally in food and drink.
- Artificial sources of radiation include medical X radiation, radioactive waste caused by testing nuclear weapons in the atmosphere and the emission of radioactive waste from the nuclear industry.
Ionising radiation is imperceptible and measuring the level of radiation is only possible using a special measuring device.
Radioactive substance emits ionising radiation creating ion-pairs in tissues meaning that some part of the molecules brake down into electrically charged particles. The spontaneous fissile ability of atomic nuclei is called radioactivity and the respective atomic nuclei are called radionuclides.
The released particles and gamma-quanta are capable of ionising the surrounding substance. That is why the flow of released particles and gamma-quanta is called ionising radiation.
Ionising radiation may be natural, for example, radioactive gas radon found in the ground emits alpha radiation. In processing X-ray images, however, artificially created X-rays are used.
For living tissues, the most dangerous radiation is ionising radiation because its qualities are most hazardous to human tissue, causing diseases such as cancer.
In Estonia, information on the radioactivity levels in the environment is collected through the annual national radiation monitoring program. Every year, more than 250 collections of environmental samples are examined. The main focus is on the radionuclides emitted into the environment by human activity.
Estonia does not have any nuclear power plants, meaning that the main threat is pollution coming from outside the border. The general gammadose rate in the atmosphere is monitored in real-time in 10 monitoring stations across Estonia and the radioactivity of airborne particles in 3 filtering stations.
Approximately half of the radiation dose affecting the residents is caused by radioactive gas radon which is found in the earth’s crust. Radon occurs naturally upon the decay of uranium. Uranium can be found more or less everywhere in the earth’s crust Therefore radon can also be found everywhere. High level of radon found in soil is connected with the Dictyonema argillite crops (Northern Estonia) and the coverage of moraine rich in granite (Southern Estonia).
Protecting a person from excessive radiation is essential. A person is subject to radiation as many times as necessary and as rarely as possible.
Radiation-related activity is based on the radiation practice license and all exposed workers must have required qualification. The latter is necessary to inspect the radiation caused by medical treatment, the radioactive substances in food products as well as contact with radiation apparatuses and sources.
Regulation of the radiation sector
The main act used by the Government and the Minister of the Environment as reference is the Radiation Act.
Radiation safety is organised by the Ministry of the Environment through the Environmental Board and the Environmental Inspectorate.
- The Ministry of the Environment develops radiation policies and legislative drafting.
- The Environmental Board issues radiation practice licenses, conducts radiation monitoring and manages the emergency notification or early warning system.
- The Environmental Inspectorate is responsible for monitoring nuclear practices.