Base metals and mercury in bryophytes and stream sediments from a geochemical reconnaissance survey of Chandalar Quadrangle, Alaska

Abstract

Stream sediments and aquatic bryophytes were used as exploration samples during a mineral reconnaissance survey of Chandalar Quadrangle, Alaska. Comparative data demonstrate that aquatic bryophytes accumulate copper, lead, zinc and mercury and locate massive sulfide mineralization better than stream sediments. Aquatic bryophytes are effective because of their ability to chemically bind dissolved trace elements, and physically trap micron-sized particulates. The former regulates mercury and manganese accumulation while the latter is more important for copper, lead, zinc and iron accumulation. Species effects seem to be negligible since statistical tests for measurable differences between bryophyte trace-element accumulations are not strongly positive. Therefore, the bryophyte data can be biogeochemically interpreted without rigorous species identification and statistical treatment. Overall, aquatic bryophytes are effective exploration samples in areas where they are abundant and stream sediments are not.