MONITORING RIVER WATER AND SEDIMENT SAMPLES BY BOTH PIXE ANALYSIS AND RADIOACTIVITY DETERMINATION

In cooperation with the Shanghai Environmental Specimen Bank (SESB) research project and in support of the Shanghai government's comprehensive plan to harness the Suzhou River, we collected water and sediment samples in the every spring season since 1998. The elemental analysis of sediment and water samples was performed by the PIXE technique using the 3 × 2 MeV NEC Tandem accelerator at the Taipei Institute of Physics. The characterization of á and â radioactive levels for water and sediment samples was performed using BH1216, low-background, radioactivity instrument at the Shanghai Institute of Nuclear Research. PIXE results showed that the content 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 once again 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 á radioactivity was a little quicker than that of â radioactivity. Further aspects of environmental data evaluation and assessment are also discussed in detail.