pl en
klatka z filmu
See more movies:
defualt movie iconikona filmu powietrzeikona filmu wodaikona filmu odpadyikona filmu hałasikona filmu różnorodnośćikona filmu zmiany
Did you know

Ionising radiation

Ionising radiation is a natural element accompanying life on our planet. Radiation from natural sources, the level of which differs in particular regions of Poland, includes cosmic radiation and radiation of natural radionuclides present in the environment. Human activity, such as medical diagnostics and radiation caused by test nuclear explosions and accidents in nuclear facilities, the biggest of which took place in 1986 in Chernobyl, cause introduction of artificial isotopes to the environment, thus disturbing the natural background of ionising radiation.

 

Having regard to the increasing energy demand of Member States, and at the same time the safety of their residents related to the functioning of nuclear energy there was introduced the Treaty Establishing the European Atomic Energy Community. Article 35 of the Treaty obligates each Member State to „set up the facilities necessary for the permanent control of the level of radioactivity in the atmosphere, water and soil and for controlling compliance with the basic standards.”

 

The share of various sources of ionising radiation in the annual average dose received by a statistical resident of Poland in 2008 is presented in the following diagram (Fig. 5.6.1.).

Fig. 5.6.1. Share of various sources of ionising radiation in the annual average effective dose received by a statistical resident of Poland in 2008 (source: NAEA)


Natural radionuclides are released to the environment as a result of anthropogenic activity, such as: mining and energy industry, fertilisation with compounds of phosphorus and potassium, and mining of uranium ores in the past. Artificial radioactive isotopes are released to the environment in a controlled or uncontrolled way. Controlled release of artificial radionuclides is a result of normal operation of nuclear reactors, spent nuclear fuel reprocessing plants and the operation of diagnostic devices and laboratories using radioisotopes. Uncontrolled released of artificial isotopes took place at the time of carrying out experimental nuclear explosions, in particular by the end of the 1950s and at the beginning of the 1960s, as well as during nuclear disasters.

In the first period after releasing, there exist in the environment both radionuclides with a short half life time (with half life times up to some weeks) and radionuclides with medium (from several months to a few years) and long half life times (starting from a few years). At a later time after the release, long-living radionuclides are of the greatest importance for the pollution of the environment, including mainly Cs-137 (Cs-137 is a beta and gamma emitter with a half life time T1/2 = 30,15 years), large quantities of which have been introduced into the environment as a result of the accident at the nuclear reactor in Chernobyl. Therefore, Cs-137 is the indicator used to control contamination with artificial radionuclides.

In Poland, there functions a network of early warning stations for radioactive contamination, which enable ongoing assessment of the radiation situation in Poland, as well as early detection of radioactive contamination.

In normal situation, the level of contamination is significantly influenced by radioactive isotopes, the concentration of which may change in a wide range (from microbecquerels to several becquerels per m³) depending on meteorological conditions. They include mainly radon 222 and radon 220, as well as products of their decay.

Beside natural isotopes, there are also recorded small concentrations of Cs-137 in the air, which are the remains of experimental nuclear explosions and the Chernobyl accident. The average monthly concentrations of Cs-137 in total faullout in 2008 were at a level of 0.04 Bq/m2. Until 1996 there were also recorded trace concentrations of Cs-134.

Of the sum of activity of total daily faullout results in the activity of annual faullout. The annual summary average of the beta activity of total faullout in 2008 in Poland amounted to 0.30 kBq/m2. The value is close to the levels recorded in the years 1985 and 1988-2007 (Fig. 5.6.2.).

Fig. 5.6.2. Beta activity of total faullout in Poland in the years 1985-2008 ( source: CIEP/SEM)


The activity of Cs-137 and, in the radiochemical way, the activity of Sr-90 are determined in monthly collective total fall. In 2008, the average monthly activity of Cs-137 in samples of faullout collected in the basic posts reached the level of less than 0.1 Bq/m2, whereas the activity of Sr-90 amounted to 0.13 Bq/m2 (Fig. 5.6.3.).

Fig. 5.6.3. Activity of Cs-134, Cs-137 and Sr-90 in the average annual faullout in Poland in the years 1986-2008 (source: CIEP/SEM)


Monitoring of radioactive concentrations in surface waters and bottom sediments justifies the statement that contamination of surface waters and sediments with Cs-137 and Sr-90 is slight. Concentrations of Cs-137 in water and bottom sediments of Vistula and their tributaries show lower values in comparison to Odra and lakes. As regards the concentration of Sr-90, the level is the same in all surface waters. Higher concentrations of Sr-90 in surface waters in comparison to the concentrations of Cs-137 are the result of easier washing out of that radionuclides by precipitation from soil to surface waters.

In Poland, global faullout from the 1950s and early 1960s and faullout after the accident at the reactor in Chernobyl are the source of Pu-239,240 in the environment. The level of plutonium isotopes in bottom sediments is low. Based on the determinations of Pu-239,240 and Pu-238 in bottom sediments, it was established that plutonium from the Chernobyl faullout was present mainly in the Vistula drainage basin. In the Odra drainage basin, existence of plutonium originating from the Chernobyl accident was found only in Głogów and Chałupki. In three lakes (Wigry, Rogóżno, Niesłysz), there was recorded a share of Chernobyl Pu-239,240, while it was Pu-239,240 from global faullout in other lakes.

The activity of Cs-137 and Sr-90 flowing with the waters of Vistula and Odra from the territory of Poland to the Baltic Sea in 2006 amounted to ca. 155 GBq, in 2007 – ca. 106 GBq and in 2008 – ca. 111 GBq.

The average concentration of Cs-137 in soil was decreasing from the value of 4.64 kBq/m2 in 1988 to 2.41 kBq/m2 in 2006. The changes in concentration of Cs-137 are caused by radioactive decay of that isotope (T1/2 30 years) and the processes of migration occurring in the environment, mainly the penetration of caesium into the deeper layers of the soil. At the same time, the concentration of Cs-134 was decreasing from 1988 in accordance with the half life time amounting to ca. 2 years, and the radionuclide was identified in soil samples until 2000, now it does exists in soil in Poland (Fig. 5.6.4.).

Pobierz dane wykresu w formacie CSV

Fig. 5.6.4 Concentrations of Cs-137 and Cs-134 in the surface layer of the soil in the years 1989-2008 (source: CIEP/SME)


Monitoring of radioactive contaminations in the environment is implemented in compliance with the programme of the State Monitoring of the Environment and the recommendations of the European Commission included in the Recommendation of 8 June 2000 concerning Articles 35 and 36 of the Euratom Treaty. Article 35 of the Euratom Treaty and the Commission Recommendation of June 2000, which require each Member State to ensure means necessary for permanent monitoring of the radioactivity of air, water and soil.

 

 


 

The existing threats require possessing knowledge of the movement of radioactive isotopes in the environment and ongoing monitoring of its state. Ensuring radiological security of Poland is related to the necessity to maintain a systematic and uniform sampling and measurements, enabling assessment of even small changes in the levels of contaminations in the environment in particular components of the environment, that is: the air, surface waters, bottom sediments and soil.

Monitoring of radioactive contaminations makes it possible to state that the contamination with the above-mentioned components Cs-137 and Sr-90 is slight, and the obtained results indicate that there did not take place new releases of radioactive isotopes to the environment.


nfos