SOLUBLE AND PARTICULATE METALS IN THE PO RIVER - FACTORS AFFECTING CONCENTRATIONS AND PARTITIONING

Fourteen metals (Ca, Mg, Al, Fe, Mn, Ba, As, Cd, Co, Cr, Cu, Ni, Pb an d Zn) were monitored over a 2-year period in the waters of the lower P o River. Concentrations in the dissolved and particulate phases were m easured, thus constructing a large database on metal variability. The influence of flow and solid transport on dissolved, particulate and to tal metal concentrations is discussed. In addition to flow rate and so lid content, biological processes seem to be one of the main factors a ffecting concentrations in the dissolved phase, while the inorganic co mponents of solids seem to control metal concentration in suspended ma tter. Data on partitioning of metals between the dissolved and particu late phases are presented, together with related information on the af finity sequence of metals for the particulate phase, and the influence of solid load on the modes of metal transport.