Observations of heavy metal accumulation in the cell walls of Fontinalis antipyretica, in a Portuguese stream affected by mine effluent

Transplants of Fontinalis antipyretica were used for assessment of metal co ntamination, caused by mine effluent, in a natural stream. A strong increas e of total Cu, Mn and Ni was observed in plants 27 days after transplantati on. Scanning electron microscopy of transplanted material showed the presen ce of concentric insoluble deposits, irregularly located on the surface of plant leaves. Such deposits were not identified on the surface of dead cell s and, presumably, are formed by biological activity of the bryophyte, The analysis of deposits by X-ray microanalysis showed strong enrichment of Mn. This could be the result of high availability of soluble Mn in an oxidativ e environment, caused by oxygen released by photosynthesis.