Sanionia uncinata, Racomitrium lanuginosum and Salix herbacea as ecological indicators of metals in Iceland

Iceland is an area practically free from pollution but threatened by long-range transported anthropogenic contaminants from mid- and low-latitudes. Therefore the load of trace elements in the environment of this island should be controlled. Accordingly in this investigation we evaluated the level of metals in rocks and soil as well as in two moss species: Sanionia uncinata, Racomitrium lanuginosum and in stems and leaves of the dwarf willow Salix herbacea. The tested hypotheses were: 1) S. uncinata and R. lanuginosum may be used as bioindicators of contaminating metals in Iceland, 2) S. uncinata is a better phytoaccumulator of these metals than R. lanuginosum because of pleated leaves, which increases their surface. No concentration of metals in the examined mosses exceeded the toxicity thresholds for plants. S. uncinata was a better accumulator of Cd, Co and Ni than R. lanuginosum, while R. lanuginosum was a better accumulator of Pb than the other moss growing together in the same sites. Both species accumulated Cr, Cu, Fe, Mn and Zn in a similar way. R. lanuginosum and S. uncinata collected in the vicinity of various local industries were correlated with the highest levels of all established concentrations of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn. Both species from sites influenced by sea spray were correlated with the highest concentration of Hg. S. uncinata and R. lanuginosum may be qualified as suitable bioindicators of metal pollution in Iceland. S. herbacea contained elevated concentrations of Cd and Zn without harming effects. Both elements in this plant also had the highest bioaccumulation factors from soil. This species was therefore a more suitable bioindicator of Cd and Zn as well as Co, Cu, Ni and Pb in Iceland than S. uncinata and R. lanuginosum.