Wildfires effects on organic matter of soils from Caramulo Mountain (Portugal): environmental implications

The investigation about wildfires has demonstrated that research should include studies on the overall assessment of the processes, thus promoting the public awareness about impacts. The aim of this study is to assess the changes on the carbon content of soils affected by wildfires in Caramulo Mountain (Portugal) to therefore identify the environmental impacts arisen from those changes. Soils from different parent rocks, affected and non-affected by wildfires, were collected. Petrographic and geochemical methods were used to identify changes caused by the wildfires in the organic fraction of soils. The results demonstrate that changes in soils composition after wildfires include the production of charcoal and pyrogenic polycyclic aromatic hydrocarbons (PAH). The incorporation of charcoal from biomass burning in soils overtime and the production of pyrolytic PAH are of environmental concern since these compounds are known to be harmful to the environment and ecosystems and are human carcinogens. The concentration of BkF-benzo[k]fluoranthene, known as probable human carcinogen, exceeds the reference values for contaminated soils. Once in soils these compounds can be removed by percolation affecting waters and, consequently, biodiversity and human health.