Naturally-occurring mosses have been sampled across Europe to monitor
the deposition of heavy metals and nitrogen from the air. This survey has been
repeated at five-yearly intervals since 1990 for heavy metals and since 2005 for
nitrogen. In 2010/2011, mosses were collected at ca. 4,500 sites in 25 countries
for heavy metals and ca. 2,400 sites in 15 countries for nitrogen. In general, the
lowest concentrations in mosses were found in northern Europe for both heavy
metals and nitrogen. The highest concentrations of heavy metals were often
observed in south-eastern Europe, whereas the highest concentrations of
nitrogen were found in parts of western and central Europe. Europe-wide the
concentration of lead (77% decline), vanadium (57%), iron (52%) and cadmium
(51%) has declined the most since 1990, whereas the concentration of copper
has declined the least (11% decline). Since 1995, the concentration of arsenic and
mercury has declined by 26% and 23% respectively. The nitrogen concentration
in mosses has hardly changed since 2005
