Bioindication of Trace Metals in Brachythecium rutabulum Around a Copper Smelter in Legnica (Southwest Poland): Use of a New Form of Data Presentation in the Form of a Self-Organizing Feature Map

Abstract

Concentrations of the elements Al, Be, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, and Zn were measured in the terrestrial moss Brachythecium rutabulum and the soil on which it grew. Soil and moss plants were sampled at sites situated 1.5, 3, 6, 9 and 15 km to the north, south, east and west of the Legnica copper smelter (SW Poland). The self-organizing feature map (SOFM) or Kohonen network was used to classify the soil and moss samples according to the concentrations of the elements. The self-organizing map yielded distinct groups of B. rutabulum and soil samples, depending on the distance from and direction to the source of pollution. When the map-identified groups of sites with similar soil metal concentrations were combined with the map-identified groups of sites with similar metal concentrations in B. rutabulum, these maps were found to correspond closely. The SOFMs accurately represented the least polluted, moderately polluted and severely polluted sites, reflecting the distribution of metals that is typical of the smelter area, caused by the prevailing westerly and northerly winds.