A combined multi-instrumental approach for the physico-chemical characterization of stream sediments, as an aid to environmental monitoring and pollution assessment.

In the present study we aimed to show on selected sediments from Kupa drainage basin, the advantages of using combined multi-instrumental approach in physico-chemical assessment of sediment quality, with respect to inorganic pollutants. Mossbauer spectroscopy and solid-state magic angel spin nuclear magnetic resonance ( 27 Al and 29 Si MAS NMR) methods are recommended in addition to commonly applied techniques: X-ray diffraction (XRD), inductively coupled plasma mass spectroscopy (ICP-MS), X-ray fluorescence(XRF) and grain size analysis, to characterize in details stream sediments. It is suggested that the application of physico-chemical methods, together with a detailed characterization of Fe and Al minerals, is useful in geochemical approach, which is complementary to biological and toxicological tests in TRIAD approach. From the difference in concentrations of pollutants determined by non destructive XRF and destructive ICP-MS (in aqua regia extract), it is possible to distinguish firmly bound elements: Cr (46-95%), As (84-97%), Pb (29-92%) from loosely bound element Mn (0-8%), which were in some cases above the level causing significant toxicity. The difference is given in percentage as relative scale. XRD method is useful to determine mineralogical composition of sediment samples. Mossbauer spectroscopy and solid state NMR methods can be used for poorly crystalline and amorphous phases. Quantitative information about the relative population of the iron species together with specific properties of the individual iron sites as oxidation states, and possible iron minerals were obtained by Mossbauer spectroscopy. In the studied samples, the presence and the ratio of tetrahedral and octahedral Al were determined by solid state 27 Al MAS NMR. From chemi