DETERMINATION OF TRACE AMOUNTS OF RARE-EARTH AND REPRESENTATIVE ELEMENTS IN WASTE-WATER SAMPLES BY CHEMICAL NEUTRON-ACTIVATION ANALYSIS

An attempt was made to establish a reliable method using chemical neut ron activation analysis for surveillance of pollutants in waste waters released by plants manufacturing various kinds of products. Since pre concentration process played important role in the entire course of th e analysis work, special precaution was taken to re-confirm that the r ecovery efficiencies for pollutant ions were satisfactory during the p reconcentration. It was also reexamined that the Langmuir's adsorption isotherm pattern well obeyed by all ions under investigation. In rece nt years, significant amounts of rare earth compounds and other raw ma terials containing representative elements have been imported and cons umed to meet the demand due to the rapid progress in new manufacturing technology. Samples were collected from ten various production lines in plants and potential pollutants were determined using the Tsing Hua Open-pool Reactor. It would be noteworthy that the specimens obtained by this preconcentration process also would be usable for Induced Cou pled Plasma-Mass Spectrometry analysis for supplementary and/or compar ison purposes.