Acid sulfate soils and their impact on surface water quality on the Swedish west coast

• Published in: Journal of hydrology. Regional studies 2022-04, Vol.40, p.101019, Article 101019
• Main Authors: Lindgren, Amanda, Jonasson, Ida Kling, Öhrling, Christian, Giese, Markus
• Format: Article
• Language: English
• Subjects: Acid sulfate soil; Agricultural drainage system; Contamination; Sweden; Water quality
• ISSN: 2214-5818; 2214-5818
• DOI: 10.1016/j.ejrh.2022.101019

Halland county, located on the Swedish west coast, with a special focus on the area around Ramsjö canal (Falkenberg municipality). This study contributes to the understanding of the development of active acid sulfate soils and environmental consequences of leaching from these soils in an area without previous investigations. Samples taken from different soil profiles in an agricultural area and water samples from the agricultural drainage system were analysed in pH, electrical conductivity, and metal concentrations. To evaluate the on-site situation, the results of the soils sample analysis were compared to the national soil classification system and the water samples to areas in northern Europe affected by acid sulfate soils. The results prove the existence of active acid sulfate soils in a coastal area in Halland. In the study region, acid sulfate soils were discovered in an agricultural area of drained wetland and peatland. Water samples taken from the drainage system and a man-made canal flowing into Kattegat Sea have low pH combined with high electrical conductivity and increased metal concentrations. This is a direct consequence of intensive leaching from the discovered acid sulfate soils in that area. Therefore, this is the first case study proving the existence of acid sulfate soils and highlighting their environmental impact on surface water quality on the Swedish west coast (i.e. outside the Baltic Sea Basin). •First determined active AS soil reported from the Swedish west coast.•AS soil occur in organic-rich postglacial sediments likely formed in shallow marine lagoons.•AS soil leakage increases acidity and metal concentrations in the surface water of the area.