Deposition av Black carbon i sjöar efter den stora skogsbranden i Västmanland 2014

Sammanfattning: Black carbon (BC) is produced during incomplete combustion of Biomass and fossil fuels. BC and other carbonaceous pollutants have characteristics that affect the climate, environment, and human health. Historically, BC emissions have been measured and monitored in the atmosphere, and BC emissions to the air are quite well documented. Deposition in water and sediments has been less studied but is important for understanding the deposition and movement of BC. This project aims to build understanding and gain knowledge about how wildfires affect the deposition of BC in lake sediments. Lake sediment samples from a wildfire-affected area have been acquired and analyzed. The wildfire took place in 2014 in Västmanland, Sweden, and was one of the most severe wildfires recorded in modern times in Scandinavia. It affected a total of 13100 ha of land. Six lakes inside the fire-affected area were selected for sampling of lake sediment. The BC concentration of the sediment was quantified with the method CTO-375 (Chemo-thermal oxidation at 375°C). The results indicate that wildfires do increase the total deposition of BC in lakes. However, the result also shows that the deposition varies between the lakes. These variations can be explained by different factors that affect the deposition of BC. These factors are related to the size of the lake and hydrological, metrological and landscape variations. The study shows that these factors have a larger effect on BC deposition in lakes than initially thought.