heavy metal

air pollution

moss monitoring

spatio-temporal pattern

Poland

heavy metals

Atmospherical pollution control

Pollution prevention

Plants

This study investigates the air deposition of heavy metals (past and recent) in Poland using a common bioindicator – moss Pleurozium schreberi. In 2010 moss samples were collected from 320 sites evenly distributed throughout the country; 297 sites coincided with those in which the 1995 survey was carried out. In green parts of mosses, the concentrations of Cd, Cu, Fe, Pb, and Zn were determined. The 2010 data were compared with those from 1995. The moss concentration of most of the studied metals decreased significantly (P<0.05) between the surveyed years: from 0.45 to 0.30 mg Cd·kg^-1, from 7.6 to 6.0 mg Cu·kg^-1, from 362 to 344 mg Fe·kg^-1, and from 18.8 to 4.9 mg Pb·kg^-1, taking into account median values. This temporal trend was dependent on region (for some provinces decreases were insignificant). The concentration of Zn did not alter in time; median values of this variable were 42.8 and 47.5 mg·kg^-1 in 1995 and 2010, respectively. The spatial patterns of the heavy metal concentrations in mosses were similar in both surveys; southern parts of Poland, industrialized and densely populated, were contaminated more than the rest of the country.