The extensive investigations of total and mobile heavy
metals concentrations in suspended matter (SPM) and bottom sediments of the upper and middle Odra
river were carried out over the years 1997-2000. Significant levels of contamination were found.
Median concentrations for Cd, Pb, Cu, Zn and As in the SPM and sediments were (mg/kg) 7.3 and
8.9, 97.2 and 119, 79.2 and 92.7, 1221 and 1158, and 52.9 and 67.9, respectively The highest
metal pollution of Odra river solids was found with cadmium, zinc, lead and arsenic. The
frequency distribution of Cd, Zn, Pb and As in both type of samples, i.e. SPM and sediments,
shows high similarity. From all metals studied, Cd, Zn and As appear to be of particular concern
because of the high levels, that appear to be bioavailable, and their high mobility. The
exchangeable and carbonatic fractions of Cd and Zn reached up to 50% of their total amount.
Besides the determination of total metal concentration, the ""mobilisation test"" of metals in
river solids is recommend for monitoring purposes, allowing evaluation of the most mobile, and
bioavailable metal fractions. The results of four years of very wide studies of Odra river system
suggest that for river monitoring purposes, the frequency and numbers of samples for chemical
analysis of both water and solids - preferably suspended matter - could be reduced to twice a
year, with few select sampling sites.