Transplants of the mosses Hypnum cupressiforme
and Pseudoscleropodium purum used as
active biomonitors of airborne trace elements were
compared in a survey carried out at Trieste (NE Italy).
Twelve elements were considered: Al, As, Cd, Cr, Cu,
Fe, Hg, Mn, Pb, Ti, V, Zn. Water-washed materials of
H. cupressiforme and P. purum, collected in a remote
area to prepare transplants, showed comparable
content of all elements, excluding Pb. Transplants of
P. purum showed a significantly higher accumulation
of Al, Fe, Pb and Ti; higher levels of Cu and V were
accumulated in H. cupressiforme. Losses of some
elements occurred in some samples of both species;
the most consistent losses regarded Cr and Mn.
Accumulation data of Al, As, Cd, Hg, Zn found in
the two transplanted sets were not correlated. Differences
in element uptake in the two mosses are likely
to depend mainly on morphology, and probably on
the different forms of emission and deposition types
of the elements. The two mosses showed an overall
accordance in discriminating sites highly and scarcely
affected by trace element depositions, although they
accumulated some elements, in particular Hg and Zn,
in different ways. P. purum proved to be a better
accumulator than H. cupressiforme, showing similar
or higher accumulation and lower loss of almost all
elements, especially those related to particulate, dry
depositions; H. cupressiforme could be effective in
detecting large-scale patterns, related to wet depositions.
These results indicate that these mosses cannot
be used interchangeably for monitoring particular
elements, and are able to provide complementary
information on different, local and long-range deposition
patterns.
