Bioaccumulation of heavy metals in selected organs of black locust (Robinia pseudoacacia) and their potential use as air contamination bioindicators

We analyzed concentrations of Cd, Cu, Fe, Pb, and Zn in bark, leaves, young shoots, pericarp, and seeds of Robinia pseudoacacia from several sites (three industrial cities and two rural villages) in southern Poland. The objective of the study was to determine the possible usefulness of various organs and tissues of this species for biomonitoring. The analyses showed that bark and leaves are organs that may serve as good bioindicators. The lowest concentrations of Cd, Pb, and Zn were found in one of the industrial cities in the area. On the other hand, the concentrations of Cd, Pb, and Zn were similar in the rural areas when compared to the concentrations observed in the cities. The high level of metal contamination of air in rural areas may be a result of the long-range transport of emissions. Also, the use of bark and leaves of R. pseudoacacia enables us to estimate the level of contamination by Fe and Cu of areas in the vicinity of railway tracks. On the basis of the data presented in this paper and the data from references, a conclusion can be drawn that the bark and leaves of R. pseudoacacia are good bioindicators of metal contamination of air in towns andcities with different traffic intensities and within the surroundings of industrial plants and railway tracks. R. pseudoacacia was also used for the first time to assess the long-range transport of emissions.