Umeå universitets logga

Acid sulfate soil comes with a broad spectrum of challenges affecting technical, economic and environmental perspectives. It can cause lowering of pH and leaching of metals and sulfate into nearby streams resulting in negative effects on the ecosystem. Management of these sediments during infrastructure projects are challenging, primarily due to the characteristics of the fine-grained sediments with poor carrying capacity. Large quantities are often transported to landfill, resulting in expensive costs. It is important to manage acid sulfate soils cautiously to prevent potential harm of the surrounding environment. During the construction of an interchange in Sikeå, northern Sweden, a large amount of acid sulfate soils has affected the construction work. Therefore, the aim of this study was to determine if any significant differences in water quality of two nearby streams could be found between upstream and downstream the interchange. The annual addition of acidic sulfate soil above the water table, within the catchment, due to isostatic land uplift was determined and compared to the amounts transported to landfill. No significant difference in water quality was found between upstream and downstream measuring points. There was a significant correlation between sulfate and conductivity but only a weak correlation between pH and sulfate. Key conclusions from this study includes that the construction of the interchange does not seem to have aggravated the water quality of nearby streams and the amount of sediment added annually above the water table by land uplift are more than twice as large as the amount that was transported to landfill.