Influence of the type of fuel used on the content of gamma radionuclides in the soot from the smoke ducts of the home furnaces

This paper presents the results of the measurements of gamma radioactive isotopes in soot samples from 15 different chimneys of household furnaces fired with various types of solid fuel. Soot samples were collected by the chimney sweep during the mandatory periodic cleaning of the chimneys. The γ-spectrometry technique using the high-purity germanium (HPGe) detector was employed for radiometry of the above-mentioned soot. It was found that the determined activity of gamma isotopes in soot is at a level similar to that in fly ash from power plants around the world. Artificial ¹³⁷Cs was detected only in the soot from the combustion of biofuel or mixed fuel. The results obtained were chemometrically analyzed to find the relationship between the fuel used and the gamma isotope content in the soot. The analysis of ¹³⁷Cs, ⁴⁰K, ²²⁸Th, and ²²⁶Ra is sufficient to differentiate between the soot obtained and tested, and it varied with the fuel type burned (fossil fuels/biofuels).