Abstract Bioaccumulation of metals in moss was studied by the absolute method using a specially designed `moss bag' technique. Bulk deposition was collected in open areas along with bulk deposition collected under moss. An absolute uptake efficiency of approximately 60% was obtained, which is in good agreement with the value obtained by a relative method. The absolute uptake efficiency varied between 0 and 92%, hence uptake of metals depends very strongly on microenvironmental conditions which can even cause leaching of metals from moss. The best retained elements were Pb, Ni, Cu and V, while Cd, Cr, Fe and Zn exhibited significantly lower uptake efficiencies. Manganese in all cases showed leaching of the element from moss.