Pollution assessment in the Trancao river basin (Portugal) by PIXE, EDXRF and isotopic analysis

This paper reports on the inorganic contamination assessment of a river bas in and local water resources in order to establish quality standards. PIXE was applied to the elemental determination of the freeze-dried water dry re sidue and EDXRF was used for the evaluation of elemental content of sedimen ts. To infer the water provenance the electrical conductivity was measured as well as the isotopic composition of surface waters using the O-18/O-16 r atio. The combined isotopic and elemental composition information enables t o establish dominant contamination contributions from the several tributari es. Moreover, the variability observed for certain parameters, associates t hem with specific basin regions as for instance: dry residue mass, conducti vity and Br, or S, Cl and As or Cr, Ni, Zn and Pb which permit to establish both pollution characterisation and their origin (agriculture. industrial, etc.). At certain locations, enhanced concentrations of elements as Cr, Cu , Zn and Pb are observed both in sediments and in the surface water. The el emental particular associations also permit to characterise pollution sourc es. (C) 1999 Elsevier Science B.V. All rights reserved.