Arsenic in the aquatic flora and fauna in areas with soils naturally high in arsenic

In the Västerbotten and Norrbotten counties in northern Sweden there are extensive areas (a few thousand km2) with elevated As-contents in soil derived from black sulphide-rich shales. In previous investigations it has been shown that the arsenic ios mobilised in wetlands under anaerobic conditions. Fe-hydroxide precipitates with as much as 2 g/kg As have been detected in streams.

This proposal aims at investigating the further fate of the arsenic in the aquatic environment. Indicators of metal and arsenic transport in the aquatic environment could be ironhydroxide precipitates (extracted by oxalate), larval capsules of midges and algae. Larval capsules contain sulphur proteines in which both heavy metal as well as arsenic may accumulate. Macroinvertebrates serve as food for fish which may act as a transfer to humans. Water, stream sediment and macroinvertebrates will be collected and analysed. Also aquatic plants and algae will be part of the investigations.