Bioconcentration of mercury and heavy metals by the bark of maple-leaf plane tree

Continuous civilization progress, urbanization, and growing level of industrialization cause the fact that the contents of mercury and heavy metals in the natural environment is increasing, posing a threat to proper ontogenesis of all living organisms. Thus it is justified to monitor and control the accumulation of the abovementioned elements in the environment. The main goal of our research was to determine whether maple-leaf plane tree (Platanus x acerifolia) may be used as a bio-indicator of the air pollutants. This tree may be found all across Central Europe, it is quite resistant to different environment pollutions, and, what is very important, it sheds the bark every autumn. The research covered a determination of the analytical procedure capable of quantitive analysis of the contents of some given heavy metals: copper, zinc, iron, mercury, and also sulfur. The results and correctness of the procedure of the preparation of the bark samples for the analysis were confirmed by the research of a certified material (BCR-062 Olive leaves). Particular attention was put to the influence of the separated stages of the sample preparation (washing, drying, grinding down), especially for the mercury analysis due to the fact that this element is characterized by high volatility. To broaden the analysis, the samples were taken from different parts of the trees: limbs, trunks, and roots, as well as from different places, such as high-traffic streets, parks, and from different cities of Poland and Europe. Total mercury contents were measured by means of automatic Mercury Analyzer MA-2. The quantification determination of the transient-metal ions was performed on a emission spectrometer with inductively coupled plasma VARIAN VISTA-MPX.