Compton suppression (CS) has increased the sensitivity of gamma spectroscopy systems tenfold, and is routinely used in laboratories
for environmental analysis and the monitoring of the CTBT. There are several different techniques available, and many more
variables to consider when designing or optimising a CS system. An overview and discussion of these is presented here.
Authors:Sonia de Almeida, Giseli Bernabé, Marisa S. Crespi, Clóvis A. Ribeiro, and Evaneide Nascimento Lima
The daily urban garbage production in the State of São Paulo, Brazil is approximately 26,000 tons/day, causing sanitation, environmental, and social problems. Dissemination of illnesses, the contamination of the
Neutron-activation analysis has been applied to the determination of mercury in a variety of environmental samples (Table
11) and so far has played an important role in the environmental research concerned with mercury pollution.
The virtues of this method as its high sensitivity, applicability to various samples make the method attractive.
On the other hand the high cost, limited availability of irradiation facilities, the time consumming analysis (due to irradiation
and cooling) are important drawbacks and limit the use of the method, particularly in routine work. With the development of
flameless atomic absorption mercury determination is more and more carried out with the aid of the latter technique. It seems,
however, that activation analysis will remain a reference method and an anchorage in the cases when other methods fail.
The Ionizing Radiation Division of the National Institute of Standards and Technology (NIST) has implemented several quality
assurance programs to provide a consistent basis for environmental-level national and international ionizing radiation measurement
credibility and comparability. These programs cut across a variety of sectors that include: (1) personnel protection; (2)
survey-instrument calibration; (3) environmental radiochemistry and (4) radiobioassay. The four basic elements of the MQA
programs are: (1) conformance to promulgated consensus criteria; (2) documented inhouse quality assurance and control practice;
(3) periodic performance evaluations using appropriate testing materials and instruments; and (4) periodic on-site assessments
by technical experts. The periodic performance evaluations are important for the demonstration of measurement traceability
to the national and international physical standards. Traceability testing, however, must be augmented by the other elements
to provide the strongest rationale for measurement assurance. This paper will describe the NIST programs and future directions
for new programs.
Measurement of 210Pb has gained a highly scientific attention due to its wide range of environmental applications. The most commonly used analytical
techniques: gamma-spectrometry, beta-counting and alpha-spectrometry were used to measure environmental samples (geological,
soil, sediment). Our paper is aiming at comparing the capabilities and limits of application of these three different analytical
techniques for 210Pb measurement in various environmental samples. In addition, analytical data of 210Pb measurements with the three different techniques (gamma-spectrometry, beta-counting and alpha-spectrometry) are discussed
to highlight the degree of comparability and the most probable sources of discrepancies and errors. Based on the demanded
investigation, one analytical technique will be chosen for routine analysis, while the other techniques, if they are available,
could be used for analytical quality assurance measures. It was essential to compare the analytical efficacy of each technique,
which differ concerning the detection limit (MDA), sensitivity, analytical effort, the duration of analysis and waiting time
The paper portrays environmental performance evaluation as a novel, innovative, applicable method or group of methods, which is not free of difficulties, but ultimately leads to the right direction. Apart from the analytical explanation and evaluation of 11 EPE methods, the article systematises them, via classifying into five clusters, based on their complexity. After that a logical sequence of using the methods is sketched, this is most relevant for practical users. With the empirical research I try to go beyond passive observation to a certain extent (statistical analysis of data - GEMS-HU surveying a representative sample of 370 manufacturing enterprises). The main objective of the presented research is to spread environmental performance evaluation, maybe slightly, but actively. It strives to enhance the application of EPE through a guidebook for practitioners, training sessions, exercises and demonstration projects. This active role might be the main methodological innovation of the current research. Only one of the three demonstration projects brought real success, but I learned more from the mistakes, than from the positive results. In the last two sections, five hypotheses are formulated and verified, scrutinising the existence, implementation and usefulness of environmental performance evaluation.
Citations in five leading environmental science journals were examined for accuracy. 24.41% of the 2,650 citations checked
were found to contain errors. The largest category of errors was in the author field. Of the five journals Conservation Biology
had the lowest percentage of citations with errors and Climatic Change had the highest. Of the citations with errors that
could be checked in Web of Science, 18.18% of the errors caused a search for the cited article to fail. Citations containing
electronic links had fewer errors than those without.
Basic aspects of pollution and the role of analytical chemistry in environmental monitoring are highlighted and exemplified,
with emphasis on trace elements. Sources and pathways of natural and especially man-made polluting substances as well as physico-chemical
characteristics are given. Attention is paid to adequate sampling in various compartments of the environment comprising both
lithosphere and biosphere. Trace analysis is dealt with using a variety of analytical techniques, including criteria for choice
of suited techniques, as well as aspects of analytical quality assurance and control. Finally, some data on trace elements
levels in soil and water samples from India are presented.
Variations in concentration of elements with different washing methods of hair-EDTA Method and Acetone Method-and different lead work employees (lead processing workers and lead glass-making workers) were studied by nondestructive neutron activation analysis. The EDTA Method removed not only the external, elements bound by surface adhesion but also the internal elements, such as Mg and Ca, existing in hair. With the Acetone Method, Zn, As and Sb concentrations in hair of lead processing workers show very high values (>2) and Cd and Co concentrations in hair of both groups show high values (1<<2), except for Pb. This suggests the effect of environmental pollution in that factory.