Exchange of mercury between atmosphere and vegetation under contaminated conditions.

Adsorption and desorption of mercury was studied under laboratory conditions using moss (Sphagnum girgensohnii) and Rye grass (Lolium perenne) at different temperatures. Desorption was also studied in a transplantation experiment. The adsorption was rapid and strong for both plant species at different temperatures (+10 to +60 degrees C) and exposure times (1 h, 1 month) while the evaporation was negligible. Also the leaching of adsorbed mercury was of minor importance. The results emphasise the importance of vegetation in removal of mercury from the atmosphere. They also confirm the suitability of moss and grass for biomonitoring purposes. The high retention of mercury in moss even at +60 degrees C indicates the possibility of using higher temperatures in pretreatment of samples for mercury analyses.