R. M. Parr

The significance of hair mineral analysis as a means for assessing internal body burdens of environmental pollutants: Results from an IAEA Co-ordinated Research Programme

During a five-year period, the International Atomic Energy Agency supported a Coordinated Research Programme (CRP) to investigate the quantitative relationship between internal body burdens of a number of elements of environmental health significance and their respective concentrations in hair. The use of nuclear-related analytical techniques, such as neutron activation analysis, X-ray fluorescence, particle-induced X-ray emission and radiotracers, was emphasized. One aspect of the CRP focused on studies in man, using autopsy cases, of mineral distribution in five tissues, i.e. liver, kidney, lung, brain and bone in addition to hair, and the elements of primary importance were As, Cd, Cu, Hg, Pb, Se and Zn. Emphasis was placed on analytical quality assurance. Hair and internal tissue samples were obtained from subjects from Bulgaria, China, the former German Democratic Republic, Hungary, Japan, Norway and Sweden.

Interlaboratory study of trace and other elements in the iaea powdered human hair reference material, HH-1

A powdered intercomparison material for trace element studies was prepared from human scalp hair and distributed to more than 100 laboratories of which 66 reported results for altogether more than 40 elements. By statistical evaluation of these data certified concentration values were derived for 20 elements, namely As, Au, Br, Ca, Cd, Cl, Co, Cr, Cu, Fe, Hg, Mg, Mn, Na, Pb, S, Sb, Se, Sr and Zn. The data also made it possible to compare different methods of analysis and to judge the value of different levels of experience on the part of the analyst concerned; these comparisons are presented here with special reference to the elements As, Cd, Hg, Pb and Sb.

Problems of chromium analysis in biological materials: An international perspective with special reference to results for analytical quality control samples

Detailed results are presented in this paper for all analytical quality control samples distributed by the IAEA including a new animal muscle intercomparison material of very low chromium content, and an attempt is made to draw some conclusions regarding likely sources of analytical error.

Determination of minor and trace elements in Turkish diet by duplicate portion technique

The minor and trace element content of diet samples from two different social population groups were determined. Samples were prepared by duplicate portion technique by colecting everything 16 subjects ate and drank during a 3-day period. Samples were homogenized, freeze-dried and elemental concentrations of Br, Co, Cr, Cs, Fe, K, Na, Rb, Sc, Se and Zn were determined by instrumental neutron activation analysis. Elemental concentrations and daily dietary intake of the elements were compared with the diets of other nations.

ON THE ROLE OF NEUTRON ACTIVATION ANALYSIS IN THE CERTIFICATION OF A NEW REFERENCE MATERIAL FOR TRACE-ELEMENT STUDIES, MIXED HUMAN DIET, H-9

A new biological reference material, which is representative of diets consumed in Finland, has been characterized by means of an intercomparison exercise conducted by the IAEA in the second half of 1985 and in 1986. Results for 35 elements received from 79 participants in 33 countries have been evaluated. A certificate of analysis has been issued with provisional certified values for 22 elements and information values for 2 elements. Neutron activation analysis (NAA) provided approximately one third of all the results reported. Instrumental NAA was used approximately 5 times as frequently as radiochemical NAA. Overall, NAA played an important role in providing useful data for the following 20 elements: Al, As, Br, Cl, Co, Cr, Cs, F, Fe, Hg, I, K, Mn, Mo, Na, Rb, Sb, Sc, Se and Zn. In comparison with the main competing non-nuclear method (usually atomic absorption spectrometry), NAA showed a larger dispersion of results for Cd, Cu, K, and Mg, and a smaller degree of dispersion for Co, Cr, Hg, and Se.

Nuclear techniques applied to air particulate matter studies

The most important fraction of aerosols with respect to human health is the respirable fraction, which has particles less than 10 μm in equivalent aerodynamic diameter (EAD), the so called PM 10 fraction. The collection of these respirable particles and the determination of their trace element composition is the focus of an IAEA Co-ordinated Research Programme (CRP). The IAEA Laboratory participated in this Programme and established collection sites for the air particulate samples on the grounds of the Atominstitute of the Austrian Universities in Vienna and the IAEA Laboratories, Seibersdorf, representing an urban residential site and a rural site. The collected samples as well as samples of simulated air filters (used also for blind controls) and control materials were analyzed sequentially and/or in sections by X-ray fluorescence (XRF), proton induced X-ray emission (PIXE), instrumental neutron activation analysis (INAA), and atomic absorption spectrometry (AAS). Results demonstrate the applicability of the PM-10 sampling approach, provided PIXE and/or INAA are used in the determinations. Reliable results can be obtained that will lead in comparable air pollution data for many regions in the world through CRP.

Simple destructive neutron activation analysis of mercury and selenium in biological materials using activated charcoal

A simple destructive neutron activation method for the determination of Hg and Se has been developed. The irradiated, sample is heated in a stream of oxygen at 1000°C, in a quartz tube in which two charcoal traps are positioned. The evaporated Hg, Se and contaminants such as Br are collected in the first charcoal trap. Only Hg is removed to the second trap by heating the first one at 750°C in a stream of nitrogen. The charcoal traps are them measured with a Ge(Li) detector. The analytical results obtained by this method for Hg and Se in several biological standard reference materials showed good agreement with the certified values.

Use of INAA, PIXE and XRF in Homogeneity Testing of New IAEA Reference Air Filters

About 250 sets of polycarbonate (Nuclepore, Costar) membrane filters loaded with two urban air particulate matter (APM) obtained in Vienna and Prague were prepared by filtration of a watter suspension of the above APM materials. The homogeneity of both bulk APM materials and the loaded filters was tested by determining a number of elements by instrumental neutron activation analysis (INAA), proton induced X-ray emission (PIXE) and micro-X-ray fluorescence (μ-XRF). Relative standard deviations due to inhomogeneity (sinh) were below 3% for many elements in the bulk APM materials. In the loaded filters, the sinh values increased significantly. Nevertheless, for up to 20 elements important in air pollution studies the sinh values were below 15%, allowing target values with a reasonably low uncertainties (up to 20%) to be derived for the future use of the filters in proficiency testing of laboratories involved in air pollution monitoring.

APPLICATIONS OF NUCLEAR ANALYTICAL TECHNIQUES IN HUMAN NUTRITION RESEARCH AS EXEMPLIFIED BY RESEARCH PROGRAMMES OF THE INTERNATIONAL ATOMIC ENERGY AGENCY

In human nutrition research, nuclear analytical techniques, particularly neutron activation analysis (NAA), are used mainly for thein vitro study of trace elements. According to work sponsored by the IAEA, up to 15 trace elements and 5 minor elements of nutritional interest may be determined in biological materials by NAA with good accuracy and precision. A programme is described in which NAA was used for the determination of 14 trace elements and one minor element in human milk. NAA also plays an important role in the certification of reference materials for nutritional studies.

Additional results for the "G-1" IAEA Intercomparison of Methods for Processing Ge(Li) Gamma-Ray Spectra

The G-1 intercomparison is one of the first undertakings of the International Atomic Energy Agency for the investigation of the performance of the routinely used evaluating programs for gamma ray spectra of semiconductor detectors. The details and the conclusions of this procedure are presented.