Concentration of the heavy metals Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb was measured in different compartments of vegetation and soil in a beech (Fagus silvatica) and a spruce (Picea abies) forest and the inventory of these elements was calculated. During a period of 3 years the heavy metal concentration in precipitation and soil water fluxes below tree root zone was determined and total element fluxes were calculated.
Annual input from the atmosphere is small (≤30%) for the metals Cr, Mn, and Ni when compared to the amounts stored in the annual increment of biomass. The percentage is higher for Fe (40 to 60%). Uptake of these metals must be supplied partly by weathering of soil minerals. Accumulation of Cu in biomass is completely accounted for by atmospheric input. Total uptake of Co, Zn, Cd, and Pb into the cycling fraction (leaves, needles) and the noncycling fraction (wood) can be accounted for or is exceeded by atmospheric input. Air pollution from industry, home firing, and motor vehicles is the probable source.
Biomass contained up to 27% of total Cd in the ecosystem, but only about 8% of Cu, 2 to 5% of Ni, Zn, and Mn, about 1% of Pb and Cr, and <0.3% of Fe and Co. Accumulation of Pb, Fe, and Co is very strong in the organic surface layer which contains up to 180 times the amount of metal reaching soil as annual litterfall, but only 3 times the amount of Mn, indicating a fast release of the metal by decomposition of organic matter.