Narrow Results

Proton Induced X-ray Emission (PIXE) and Instrumental Neutron Activation Analysis (INAA) techniques were used to measure the contents of 45 elements in 150 air-filter samples collected by cascade impactor with 8 stages at 10 sites in Beijing-Tianjin area of China during the periods of the winter of 1983 and the summer of 1984. It was noticed that the toxic elements such as As, Sb, Se, Pb, Hg, Cu and Ni were mainly enriched in fine particles with diameter less than 2 um. The major seven sources of coal burning, soil dust, oi1 burning, sea-salt aerosol, motor vehicle emission, limestone dust and industrial refuse attributing to the pollution in Tianjin area were identified by Chemical Elements Balance method (CEB). Among them the most important sources were the soil dust and the emission from coal-combustion followed by contributions from limestone and industrial refuse.

The recent methodological developments and particularly the recent applications of nuclear analytical techniques (mainly PIXE and INAA) for measuring minor and trace elements in various types of environmental samples are reviewed. The sample types covered range from atmospheric aerosols over miscellaneous air topics (e.g., emissions, wet and dry deposition) to various solid environmental materials and samples from the aqueous environment. A fairly comprehensive overview is given of the research on atmospheric aerosols. For the other sample types, the trends in the research are indicated and selected examples of applications are presented. It is shown that the nuclear analytical techniques are very valuable for the multielement analysis of solid environmental samples. Furthermore, PIXE is particularly suitable for analyzing atmospheric aerosol samples.

PIXE technique was applied to measurement of trace elements in total diet samples collected in Japan for estimation of their daily dietary intake. Results of PIXE analysis were compared with INAA Concentration of Cl, K, Mn and Zn by PIXE analysis well agreed with the results from NAA, while Ca, Fe and Cu showed different results between these two techniques. Preliminary data of elemental concentrations in Mate-cha, a kind of tea popular in South America, determined by ICP-AES indicated a little higher concentration of Cu than that by PIXE and much lower value than that by INAA For Zn. concentrations by PIXE and ICP well agreed to each other, while INAA gave much lower value. Japanese internal radiation doses by ¹³⁷Cs and ⁹⁰Sr were estimated to be 2.30µSv/year and 1.27µSv/year respectively as the effective dose equivalents using the daily intake data obtained for K and Ca.