Anthropogenic accumulation based on chemometrics of the radionuclide K-40 in tropical soils in the northeast Brazil

The continuous use of fertilizers can increase the radionuclides levels in soils, and their accumulation and concentration are related to their characteristics and the various processes of use and soil occupation. Analyzing data from radiometric and pedological measurements often demands the use of more robust tools for better integration of results. This work presents the results of a study to evaluate the accumulation of K-40, in an area of the Zona da Mata region in Pernambuco, Northeastern Brazil, due to the contribution of natural or artificial sources. K-40 activity concentration was measured by high resolution gamma spectrometry in 108 soil samples, as well the organic matter content and particle size distribution. Results showed the K-40 activity ranged from 103 to 1843 Bq.Kg(-1), with the arable soils showing levels above the world average value (420 Bq.Kg(-1)). A higher prevalence of K-40 was observed on arable soils, regardless of soil type, organic matter content, depth or texture. Agricultural activities increased of K-40 levels in different degrees, depending on the type of crop used, with an accumulation factor of up to 4 times greater compared to soils not impacted by agricultural activities. The radiochemometric diagnosis maded it possible to draw up a strategic management plan to improve the management practices of family farming in order to maximize production efficiency, and promote the conservation of natural resources and environmental preservation.