The highly polluted Lambro river(N. Italy): Dissolved and solid transport of Cu, Cr and Fe

Abstract

The modes of transport of Cu, Cr and Fe have been studied in the river Lambro, a highly polluted tributary of the river Po. Twenty-one samples were taken over the period November 1990–March 1992. Fe concentration was consistent with the geochemical nature of the drainage basin, while the high enrichment factors for Cu and Cr (7 and 18 respectively) confirmed a major anthropic contribution to the levels of these metals. The influence of flow, suspended matter and other factors on metal transport by the dissolved and particulate phases were analysed. Suspended matter, as expected, was found to be the main metal transport vehicle. Comparison of Lambro partitioning coefficients with those for the Po, and with other published values, revealed that dissolved phase transport was also important, as found for other industrially polluted rivers. Total metal concentrations were mainly influenced by water flow. The annual metal loads for the Lambro were estimated from the data and indicate that the Lambro contributes 20% of Cu, 9.4% of Cr and 3.6% of Fe to pollution loads in the Po.