engleski

Distribution of Ra-226 in the surface soil in the vicinity of the thermal power plant Plomin (Croatia)

Purpose of this study was to determine the long term influence of the thermal power plant (TPP) Plomin in Istria peninsula (Croatia) on the possible contamination of the surrounding soil by the radionuclides from the emitted coal ash. Coal naturally contains radionuclides of the U-238 and Th-232 decay series, as well as K-40, which concentrate in ash due to coal combustion, several times more in comparison with their content in coal or surface soil. This preliminary study will focus only on the Ra-226 which is, along with its decay products, responsible for the largest part of the dose received by humans from the naturally occurring radionuclides. Ra-226 is an alpha emitter with a half-life of 1622 years. It has similar chemical characteristics to calcium which can lead to calcium replacement in bones if it enters in an organism and is therefore harmful for people. Furthermore, Ra-226 decays to Rn-222, with a halflife of 3.8 days, which is a noble gas and can easily be inhaled into the human organism, known for causing lung cancer. The main assumption of this research was that radionuclides could be dispersed into the environment from the plant stack and from the ash piles next to the TPP due to the rainfall and the wind flow. Considering that Ra-226 is a terrestrial radionuclide, present in all rocks and soils in variable amounts, the main purpose was to evaluate if the natural radioactivity of the area was elevated due to influence of the flying ash and/or bottom ash produced by the coal combustion. The results were compared with the control sample and with the average soil value.

Ra-226 ; soil ; Plomin ; coal combustion

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