INTEGRATED CHEMICAL AND BIOLOGICAL EVALUATION OF THE QUALITY OF THE RIVER LAMBRO (ITALY)

The aim of this study was to integrate hydrochemical and biological data in order to obtain a picture of the water quality along the River Lambro, considered to be one of the most polluted rivers in Italy. Biological sampling with artificial substrates was undertaken in February and May 1991 together with water sampling. Significant longitudinal variations between stations 1 and 2 were observed for temperature, conductivity and dissolved oxygen. Station 3 (Villanterio), situated on the southern tributary, showed a higher degree of pollution than the stations along the main course of the Lambro. E.B.I. and B.M.W.P. score gave a similar picture. A multivariate analysis (CCA) of the taxonomical and chemical data showed the greater influence of the environmental parameters conductivity and D.O. on the macroinvertebrate community structure. All the methods confirmed the strong impact of the Milan area on the river; two different environmental situations could be distinguished on the basis of characteristical groups of taxa. The artificial substrates combined with multivariate analysis proved to be a useful combination in the study of this river.