Sediment chemistry and the potential toxicity to benthic invertebrates in sediments affected by acid sulfate soils : A study on freshwater and marine sediments in Västerbotten, Sweden

Abstract: The leakages of metals from acid sulfate soils and their potential toxicity to benthic invertebrates were studied in the sediment profiles of Lillkvasjön and Lövselefjärden - a lake and an estuary known to be affected by acid sulfate soils - in Västerbotten, northern Sweden. The concentrations of 25 different elements were analyzed throughout both sediment profiles through X-Ray Fluorescence (XRF) Spectrometer analysis. Organic matter was measured through loss-on-ignition (LOI). By performing correlation analysis and normalizations to LOI on all sediment variables, Cu, Fe, Ni, Pb, S and Zn were found to be leached from acid sulfate soils to both sites, while Mg and Mn were related to leakages from acid sulfate soils in Lövselefjärden. The concentrations of Cu (195 mg kg-1), Ni (55 mg kg-1), Pb (90 mg kg-1) and Zn (398 mg kg-1) in the surface sediment of Lövselefjärden were classified as potentially toxic to benthic invertebrates. In Lillkvasjön, Cu (210 mg kg-1) and Ni (87 mg kg-1) were classified to have an increased risk of negative impacts on benthic invertebrates, while the concentrations of Pb (121 mg kg-1) and Zn (329 mg kg-1) were likely to low to have any negative effects. These results strengthen previous finds of impacts from acid sulfate soils in the two catchment areas and elucidate the importance of further studies on the impact of acid sulfate soils on benthic invertebrates.