Extensive dispersion of metals from hemiboreal acid sulfate soil into adjacent drain and wetland

Extensive red/brown precipitates of unknown origin and composition have caused ecological degradation a wetland nature reserve (the Water Kingdom Biosphere Reserve) in the hemiboreal zone south Sweden. Chemical analyses samples containing showed strong dominates Fe elevated levels rare earth elements (REEs), Be, U. In addition, synchrotron-based indicated that these was bound largely akageneite and/or schwertmannite. Under nearby farmlands, acid sulfate soils, developing on sulfide-bearing sediments notorious for abundant export metals, were identified found to be widespread, deep (down sampling depth 180 cm or deeper), very acidic (minimum pH range soil profiles: 2.8–3.5). In-between farmland central drain can act as both transporter sink leached from soils. had accumulated strongly concentrations Al (15%), ∑REE (2725 mg/kg), Be (15 U (37 mg/kg). Based data features, conceptual model areas proposed. The releases several major trace elements, including Fe2+, which are transported waters via drainpipes where increases, causing extensive precipitation Al, REEs, well Fe2+ oxidation formation oxyhydroxides oxyhydroxysulfates. A substantial part water, however, remains solution, so when this water is ultimately pumped wetland, large amounts together with significant finally oxidized, precipitated retained. Yet other abundantly soils (Mn, Zn, Ni, Co, Cd), not any recipients therefore most likely been beyond our sites has thus reached further out ecologically sensitive wetland.