Moss bioconcentration of trace elements around a FeSi smelter: modelling and cellular distribution

This article describes an evaluation of contamination by Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se and Zn in the surroundings of a FeSi smelter, by measurement of tissue levels of the elements in terrestrial mosses growing in the area. The total concentrations of As, Cu and Fe were modelled by surface response fitting. Use of the sequential elution technique (using EDTA as the extracellular displacing agent) enabled determination of the concentrations of Cu and Fe in the extra- and intracellular and insoluble particulate fractions. A gradient of exponentially decreasing contamination with increasing distance from the factory was found with all fractions except for the extracellular fraction of Zn. The advantages of using of the intracellular rather than the total fraction is discussed, i.e. the former clearly shows the dose–effect relationship and reveals the concentration-distance gradients as clearly as the latter, and the difficulties associated with toxicological risk evaluation are reduced (because of different bioavailabilities of the contaminants it is not possible to infer their concentrations from total fractions).