PIXE and radioactivity measurements for elemental determination in river water and sediment samples

Abstract

In order to evaluate the evolution of contamination we collected river water and sediment samples in the every spring season since 1998. The elemental analysis of water and sediment samples was performed by PIXE using the 3X2 MeV NEC Tandem accelerator at the Taipei Institute of Physics. The characterization of alpha- and beta-radioactive levels for water and sediment samples was performed by a BH1216, low background radioactivity instrument at the Shanghai Institute of Nuclear Research. The PIXE results showed that the elemental contents of Cl, K, Ca, Cr, Mn, Fe, Zn and Pb in river water gradually decreased with the rising tide. At high tide, their concentrations were minimum and then increased toward the ebb tide. The analysis also demonstrated that the radioactivity of water samples had been gradually decreasing year by year. It was found that the decreasing rate of alpha-radioactivity was a little quicker than that of beta-radioactivity. Further aspects of environmental data evaluation and assessment are also discussed.