Applied environmental metrology for studying health-pollution interactions

Nuclear and isotopic techniques are valuable tools in assessing the levels of environmental pollution by toxic elements and for studying how these contaminants affect human health. More than 90 counterparts from 55 countries around the world have participated in projects on these topics, supported by the International Atomic Energy Agency (IAEA), during last ten years. With the support of the IAEA, for example, an appropriate metrology for compositional characterization of size fractionated airborne particulate matter was developed, verified and implemented in more than 40 countries. This paper reviews the development and application of environmental metrology tools involving nuclear analytical and isotopic techniques, as seen from the particular perspective of IAEA programmes.     

Analytical Intercomparison Exercises and Harmonization within Environmental Laboratories from Developing Countries

Abstract

Since the early 60's, the IAEA implements a Quality Assurance (QA) programme for the Member States. As part of this programme, the IAEA organized more than 150 analytical intercomparison exercises and produced more than 70 Certified Reference Materials for a wide range of determinands, encompassing radionuclides, trace elements, petroleum hydrocarbons, pesticides and PCBs. From the IAEA — Marine Environment Laboratory in Monaco, analytical Quality Assurance services are provided for non-nuclear contaminants in marine materials.

Results of recently organized worldwide intercomparison exercises using the sample materials IAEA-142 (mussel tissue homogenate) and IAEA-140 (seaweed homogenate), show that some progress was achieved worldwide in the analyses of the more common environmental contaminants. However, results also show that difficulties in obtaining accurate data for trace elements and especially for organic contaminants are still widespread, particularly in developing countries. Therefore, the success of international cooperative programmes as well as of many regional environmental monitoring programmes, depends on improved quality and comparability of data which has to be achieved still through reinforced Quality Assurance programmes. To this aim, the IAEA/UNEP/IOC-UNESCO inter-agency programme on marine pollution promotes the adoption of Reference Methods for harmonization of techniques used in developing and developed countries, organizes frequent intercomparison exercises, and produces certified marine Reference Materials which are made available to laboratories worldwide.     

Neutron Activation Analysis in the IAEA Projects on Air Pollution

The International Atomic Energy Agency (IAEA) has been promoting studies on air pollution since 1992. During the period 1992–1999 there have been six major co-ordinated research and regional technical co-operation projects in which 77 counterparts from 40 Member States actively participated. The studies supported by the IAEA have included ambient and workplace airborne particulate matter, the use of appropriate plant biomonitors and a series of laboratory intercomparison exercises in support to these projects. Recent and current IAEA projects in this field are reviewed in the light of the application of neutron activation analysis, which has been used as a major analytical technique by more than two thirds of the counterparts, and contributed also approximately two thirds of all analytical results for the intercomparison exercises.     

Assessment of element-specific homogeneity in reference materials using microanalytical techniques

The IAEA established in 1994 a co-ordinated research programme (CRP) on "Reference Materials for Microanalytical Nuclear Techniques" as part of its efforts to promote and strengthen the use of nuclear analytical technologies in member states with the specific aim of improving the quality of analysis of nuclear, environmental, and biological materials. The objectives of this initiative were: to identify suitable biological reference materials which could serve the needs for quality control in microanalytical techniques; to evaluate existing CRMs for use in microanalytical investigations; to evaluate appropriate sample pretreatment procedures for materials being used for analysis with microanalytical techniques; to identify analytical techniques which can be used for characterisation of homogeneity determination, and to apply such techniques to the characterization of candidate reference materials for use with microanalytical techniques. The CRP lasted for 4 years and seven laboratories and the Agency's Laboratories in Seibersdorf participated. A number of materials including the candidate reference materials IAEA 338 (lichen) and IAEA 413 (single cell algae, elevated level) were evaluated for the distribution of elements such as Cl, K, Ca, Cr, Mn, Fe, Zn, As, Br, Rb, Cd, Hg, and Pb. The results obtained during this CRP suggest that: each element exhibits its characteristic distribution in a matrix described by the "Ingamels' sampling constant" or the "relative homogeneity factor" of Kurfuerst; both concepts are valid over a large range of sample mass used for analysis (from 0.1 g to around 100 mg); and materials being characterised quantitatively for element homogeneity could be used for the experimental determination of total uncertainty of other analytical techniques. As far as we are aware this is the first time the concept of quantitative characterisation of homogeneity has been applied to potential reference materials and the first demonstration of the feasibility and usefulness of the concept with particular emphasis on enhancing quality control opportunities for microanalytical techniques.     

Reliability and performances of a high-purity gamma spectrometry system used for environmental measurements

Proficiency testing is among the most methods to assess the accuracy of the analytical data produced by laboratories. The results presented in this paper show the performance of the laboratory for three intercomparisons organized by Radionuclide Metrology Laboratory (RML) and by IAEA, in which SALMROM laboratory have participated in three consecutive years. The feedbacks from the final reports from RML and IAEA demonstrate the performance of the laboratory where 34 out of 39 pass all acceptance criteria of the test. The rest of five results which failed served to improve the laboratory analysis and to optimize accuracy measurements. The overall results of the proficiency tests point out the reliability and traceability of the gamma spectrometry system used for environmental measurements.     

Recent developments in radiometric and mass spectrometry methods for marine radioactivity measurements

The most important recent developments in radiometric techniques have been the operation of high efficiency HPGe detectors with anticosmic or antiCompton shielding often placed underground, ship-board measurements of ²³⁴Th using gamma-spectrometry or beta-counting and underwater gamma-spectrometry. In mass spectrometry techniques, the availability of high resolution ICP-MS and applications of AMS for the analysis of long-lived radionuclides have opened doors for investigations which previously required too large samples, or were not possible because of lack of sensitivity. These developments are illustrated by several examples of marine radioactivity studies, which include contaminated sites (e.g., Fangataufa Atoll) and open ocean studies (e.g., the Atlantic Ocean) as well as analyses of IAEA reference materials. A comparison of Pu results obtained by alpha-spectrometry, ICP-MS and AMS has shown that a reasonably good agreement has been obtained between all three methods.     

Nuclear activation techniques in the life sciences 1978

The proceeding of the IAEA symposium held in 1978 on nuclear activation techniques in the life sciences are reviewed. A total of 56 papers are reviewed on methodology, analytical quality control, comparisons between neutron activation analysis and other methods, and applications of activation analysis in biology and medicine (including in-vivo activation analysis) and in public and environmental health. The materials analysed in the papers are adjusted in connection with the elements determined and the purposes of the study. Those elements are tabulated together with the analytical methods used for the element determination. The standard reference materials analysed for the check of the reliability of analysis are also arranged. Proc. Symp. Nuclear Activation Techniques in the Life Sciences, IAEA, Vienna, 1978.     

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.     

Quality system implementation in Member States of the IAEA

The International Atomic Energy Agency (IAEA), through its Technical Co-operation Programme, has supported the establishment of many nuclear analytical and complementary laboratories in Member States. This included the development of capabilities for the use of various nuclear analytical techniques that include alpha, beta, and gamma spectrometry; radiochemical analysis; neutron activation analysis; energy dispersive X-ray fluorescence analysis; and total reflection X-ray fluorescence. As economic, ecological, medical, and legal decisions are frequently based on laboratory results, they need to be based on accepted national and international standards.The IAEA has taken up this important issue to enhance and foster the competitiveness of nuclear analytical laboratories with the consideration that non-nuclear capabilities are equally important. The projects aim at enhanced quality awareness, a concise system for documentation, establishment of standard operating procedures, procedures for validation of methods, surveillance of method performance, systems for sample management, regular qualification of personnel, client liaison and safety. These projects follow the ISO/IEC 17025 standard and promote participating laboratories to maintain a self-sufficient quality system by which they might be able to obtain national accreditation.This contribution describes the general concept of these projects and discusses some of the results achieved.     

Nutritional and Environmental Properties of Algal Products Used in Healthy Diet by INAA and ICP-AES

Spirulina platensis alga sampled in the Caribbean Sea and seven other commercial algal products available on the Italian market of different origin and aspect, have been analyzed by instrumental neutron activation analysis (INAA) and inductively coupled plasma-atomic emission spectrometry (ICP-AES). By neutron irradiation and -ray spectrometry (INAA), as many as 20 elements could be measured instrumentally without any chemical treatment. Cu, Mg, Mn and Pb were determined after dissolution of the sample by ICP-AES. The cross-checking of the data, specifically by comparing those of Ca, Cr, Fe and Zn, obtained by the two techniques was found to be in good agreement. Special attention from analytical and nutritional point of view has been devoted to the toxic metals. The measurements have been carried out employing the reference algal material prepared by International Atomic Energy Agency (IAEA).     

Dietary intakes of essential trace elements: Results from total diet studies supported by the IAEA

Summary The International Atomic Energy Agency (IAEA) has, for many years, supported research on human dietary intakes of trace elements taking advantage, for analysis, of the possibilities offered by nuclear techniques, particularly neutron activation analysis (NAA). This paper summarizes the results obtained from studies in more than 20 countries in which special emphasis was placed on the application of reliable methodologies (written protocols, special equipment, analytical quality control, etc.). Considerable variation was observed among dietary intakes of essential minor and trace elements though most elements showed a pattern of adequate nutrition in most countries. However, for some elements such as calcium, iodine, iron and zinc, the intakes in many countries were lower than the dietary requirements.     

Stripping voltammetry for the determination of trace metal speciation and in-situ measurements of trace metal distributions in marine waters

Progress in marine chemistry has been driven by improved sampling and sample handling techniques, and developments in analytical chemistry. Consequently, during the last 20 years our understanding of marine trace metal biogeochemistry has improved a great deal. Stripping voltammetric techniques (anodic stripping voltammetry and adsorptive cathodic stripping voltammetry) have made an important contribution to this understanding. The selectivity and extremely low detection limits have made stripping voltammetry a widely used technique for trace metal speciation and trace metal distribution measurements in seawater. Stripping voltammetry is very suitable for ship-board and in-situ applications because of the portability, low cost and capability for automation of the voltammetric instrumentation. Future developments in stripping voltammetry can be expected in the field of stand-alone submersible voltammetric analysers, capable of continuous trace metal measurements. Future applications of stripping voltammetry can be found in the interactions between trace metal speciation and growth and the functioning of organisms in pristine and metal polluted marine waters.     

Quality assurance in analytical chemical laboratories: Towards harmonization and integration of current standards

This article presents the results of a comparative study of the main quality assurance (QA) and good laboratory practice (GLP) regulation systems and standards for analytical chemical laboratories currently being applied in Europe. A growing number of laboratories are being confronted with the need to cope with two or more of these systems, which involves separate audits and inspections for certification and accreditation. As these regulatory systems have essentially the same aims, there is an increasing interest in harmonization of QA and GLP guidelines. As a first step in exploring the possibilities of harmonization, similarities and differences of the current systems, compiled in the form of cross reference tables, have been analyzed (from a laboratory practice point of view) by a study group of EURACHEM, The Netherlands. The conclusions of this study have recently been endorsed by the Committee of EURACHEM Europe.     

Comparison of neutron activation analysis with other analytical techniques for the determination of inorganic constituents of milk powder

The contribution of different analytical techniques to the results of a recent IAEA intercomparison (A-11) of the determination of the inorganic constituents of a milk powder sample is discussed. In all, 43 laboratories from 24 countries reported results on 40 elements, “recommended” concentrations for 14 elements were established. NAA was the most important of the 9 techniques used in this run, it contributed 40% of all the results and all the results for 7 elements. Accuracy and precision of NAA proved to be good compared to those of other methods.     

Level of some minor and trace elements in Bangladeshi meat products

An investigation on the level of some minor and trace elements in some varieties of meat (beef, mutton and chicken) consumed in Bangladesh is reported. In this study, protoninduced X-ray emission (PIXE) and radioisotope-induced X-ray fluorescence (XRF) techniques were used for analytical measurements. In PIXE measurements, the samples were exposed to the proton beam in air as 1 mm thick pellets and irradiated with 2.0 MeV protons having the beam intensity of 30 nA for characteristic X-ray excitation, whereas in XRF, the samples were excited for 5000 seconds with a 10 mCi¹⁰⁹Cd annular X-ray source. The elemental concentrations of Ca, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb and Sr were determined in the samples by comparison with X-ray yield curves constructed from IAEA and NBS standard reference materials. The significance of the results is dicussed in relation to human health and diseases.This research received financial support from the International Atomic Energy Agency, Vienna, under the research contract RC-4265/RB.     

Quality and the development of reference materials, including the role of traceability and comparability

The global recognition that quality is an economic issue is requiring analytical chemists to look at the chemical measurement process in a way that has not been done before. Much work has been done in certifying reference materials, writing measurement protocols, creating measurement networks, developing analytical measurement techniques and other efforts to make good measurements. This article explores the meaning of quality in chemical measurements and discusses quality in terms of credibility, reliability, traceability and comparability. The importance of understanding the contribution of comparability and traceability to quality in chemical measurements and chemical metrology is emphasized.     

Different approaches to legal requirements on validation of test methods for official control of foodstuffs and of veterinary drug residues and element contaminants in the EC

 In order to ensure food consumer protection as well as to avoid barriers to trade and unnecessary duplications of laboratory tests and to gain mutual recognition of results of analyses, the quality of laboratories and test results has to be guaranteed. For this purpose, the EC Council and the Commission have introducedprovisions – on measures for quality assurance for official laboratories concerning the analyses of foodstuffs on the one hand and animals and fresh meat on the other, – on the validation of test methods to obtain results of sufficient accuracy. This article deals with legal requirements in the European Union on basic principles of laboratory quality assurance for official notification to the EC Commission and on method validation concerning official laboratories. Widespread discussions and activities on measurement uncertainty are in progress, and the European validation standards for official purposes may serve as a basis for world-wide efforts on quality harmonization of analytical results. Although much time has already been spent, definitions and requirements have to be revised and further additions have to be made.     

Analytical Quality Assurance Procedures Developed for the IAEA's Reference Asian Man Project (Phase 2)

Analytical quality assurance procedures adopted for use in the IAEA Co-ordinated Research Project on Ingestion and Organ Content of Trace Elements of Importance in Radiological Protection are designed to ensure comparability of the analytical results for Cs, I, Sr, Th, U and other elements in human tissues and diets collected and analysed in nine participating countries. The main analytical techniques are NAA and ICP-MS. For sample preparation, all participants are using identical food blenders which have been centrally supplied after testing for contamination. For quality control of the analyses, six NIST SRMs covering a range of matrices with certified and reference values for the elements of interest have been distributed. A new Japanese reference diet material has also been developed. These quality assurance procedures are summarized here and new data are presented for Cs, I, Sr, Th and U in the NIST SRMs.     

Statistical evaluation of recorded knowledge in nuclear and other instrumental analytical techniques

Summary The main points addressed in this study are the following: Statistical distribution patterns of published literature on instrumental analytical techniques 1981–1984; structure of scientific literature and heuristics for identifying active specialties and emerging hot spot research areas in instrumental analytical techniques; growth and growth rates of the literature in some of the identified hot research areas; quality and quantity in instrumental analytical research output.

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Statistische Auswertung von Veröffentlichungen in nuklearen und anderen instrumentellen analytischen Techniken

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Presented at the IAEA Advisory Group Meeting on Comparison of Nuclear Analytical Methods with Competitive Methods, October 3–7, 1986, Oak Ridge, TN, USA     

IAEA analytical quality assurance programmes to meet the present and future needs of developing countries

For many years the International Atomic Energy Agency (IAEA) has been promoting analytical quality assurance and quality control in its Member States with emphasis on measurands that are amenable to analysis by nuclear and related techniques, i.e. radionuclides, trace elements, and stable isotopes. This paper reviews briefly the rationale for some of these activities, particularly in relation to the needs of participants in developing countries arising out of co-ordinated research programmes, technical co-operation projects and global and regional networks. Emphasis is given to biological and environmental reference materials with a matrix of natural origin. Also described are some activities arising out of the requirements of ISO-25 and other relevant international quality standards.