Retrospective analysis of heavy metal concentrations at selected locations in the Federal Republic of Germany using moss material from a herbarium

In this study, herbarium moss samples taken from selected locations and in different years between 1845 and 1974 were compared with samples from similar locations taken in the context of the German moss monitoring programme of 1991. Samples have been analyzed for the heavy metals arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), nickel (Ni), vanadium (V) and zinc (Zn). In the herbarium material, the lowest concentrations were found in the early period between 1845 and 1901; the levels rose over the course of time. In general, the element concentrations of the moss samples taken in 1991 are lower than those of the mosses from the herbarium. However, the reverse is true of the elements V and Ni. The differences in concentrations found between the herbarium material and the 1991 moss monitoring samples document both the effects of air pollution resulting from progressive industrialization in the earlier periods and the reduction of heavy metal emissions due to improved methods of preventing air pollution at the present time. Moreover, the results for V and Ni can be interpreted as showing a change in the use of primary sources of energy.