If an eBook is available, you'll see the option to purchase it on the book page. View more FAQ's about Ebooks. Each report has been subjected to a rigorous and independent peer-review process and it represents the position of the National Academies on the statement of task. The Bhopal Disaster of resulted in the death of around 2, residents living near chemical plants and irreversible injuries to more than 20, other residents.
- Sonata in D major (K443/P376/L418;
- The Insiders Guide to Boat Cleaning and Detailing: Professional Secrets to Make Your Sail-or Powerboat Beautiful;
- Mathematical Models for Suspension Bridges: Nonlinear Structural Instability!
- Russia-Cyprus Relations: A Pragmatic Idealist Perspective!
- The Human Rights of Aliens under International and Comparative law (International Studies in Human Rights)!
- We also offer.
- Ammonia exposure and hazard assessment for selected household cleaning product uses?
The disaster emphasized the need for governments to identify hazardous substances and to aid local communities in developing plans for emergency exposures. The COT, who had published many reports on emergency exposure guidance levels at the time, designated the task to a subcommittee. Four years later the National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances NAC was created with a focus on identifying, reviewing, and interpreting relevant toxicologic and other scientific data and developing acute exposure guideline levels AEGLs for high-priority, acutely toxic chemicals.
In Acute Exposure Guideline Levels for Selected Airborne Chemicals:Volume 4 , the NAC outlines acute exposure guideline levels for chlorine, hydrogen chloride, toluene 2,4, hydrogen fluoride, 2,6-diisocyanate, and uranium hexafluoride. The National Academies Press and the Transportation Research Board have partnered with Copyright Clearance Center to offer a variety of options for reusing our content.
You may request permission to:. For most Academic and Educational uses no royalties will be charged although you are required to obtain a license and comply with the license terms and conditions. For information on how to request permission to translate our work and for any other rights related query please click here.
For questions about using the Copyright. Finding similar items Read Online. View Cover. Login or Register. E-mail this page Embed book widget. What is an eBook? Biological indicators can be used for various purposes in occupational health practice, in particular for 1 periodic control of individual workers, 2 analysis of the exposure of a group of workers, and 3 epidemiological assessments. The tests used should possess the features of precision, accuracy, good sensitivity, and specificity in order to minimize the possible number of false classifications.
A reference value is the level of a biological indicator in the general population not occupationally exposed to the toxic substance under study. It is necessary to refer to these values in order to compare the data obtained through biological monitoring programmes in a population which is presumed to be exposed. Reference values should not be confused with limit values, which generally are the legal limits or guidelines for occupational and environmental exposure Alessio et al.
When it is necessary to compare the results of group analyses, the distribution of the values in the reference group and in the group under study must be known because only then can a statistical comparison be made. In these cases, it is essential to attempt to match the general population reference group with the exposed group for similar characteristics such as, sex, age, lifestyle and eating habits. To obtain reliable reference values one must make sure that the subjects making up the reference group have never been exposed to the toxic substances, either occupationally or due to particular conditions of environmental pollution.
In assessing exposure to toxic substances one must be careful not to include subjects who, although not directly exposed to the toxic substance in question, work in the same workplace, since if these subjects are, in fact, indirectly exposed, the exposure of the group may be in consequence underestimated. Another practice to avoid, although it is still widespread, is the use for reference purposes of values reported in the literature that are derived from case lists from other countries and may often have been collected in regions where different environmental pollution situations exist.
Periodic monitoring of individual workers is mandatory when the levels of the toxic substance in the atmosphere of the working environment approach the limit value. Where possible, it is advisable to simultaneously check an indicator of exposure and an indicator of effect. The data thus obtained should be compared with the reference values and the limit values suggested for the substance under study ACGIH Analysis of a group becomes mandatory when the results of the biological indicators used can be markedly influenced by factors independent of exposure diet, concentration or dilution of urine, etc.
In order to ensure that the group study will furnish useful results, the group must be sufficiently numerous and homogeneous as regards exposure, sex, and, in the case of some toxic agents, work seniority.
The more the exposure levels are constant over time, the more reliable the data will be. An investigation carried out in a workplace where the workers frequently change department or job will have little value. For a correct assessment of a group study it is not sufficient to express the data only as mean values and range.
Acute Exposure Guideline Levels for Selected Airborne Chemicals: Vol 1
The frequency distribution of the values of the biological indicator in question must also be taken into account. Data obtained from biological monitoring of groups of workers can also be used in cross-sectional or prospective epidemiological studies. Cross-sectional studies can be used to compare the situations existing in different departments of the factory or in different industries in order to set up risk maps for manufacturing processes.
A difficulty that may be encountered in this type of application depends on the fact that inter-laboratory quality controls are not yet sufficiently widespread; thus it cannot be guaranteed that different laboratories will produce comparable results. Prospective studies serve to assess the behaviour over time of the exposure levels so as to check, for example, the efficacy of environmental improvements or to correlate the behaviour of biological indicators over the years with the health status of the subjects being monitored.
The results of such long-term studies are very useful in solving problems involving changes over time. A given level of exposure considered safe today may no longer be regarded as such at some point in the future.
Do the Work: Overcome Resistance and Get Out of Your Own Way
Some ethical considerations arise in connection with the use of biological monitoring as a tool to assess potential toxicity. One goal of such monitoring is to assemble enough information to decide what level of any given effect constitutes an undesirable effect; in the absence of sufficient data, any perturbation will be considered undesirable. The regulatory and legal implications of this type of information need to be evaluated. Therefore, we should seek societal discussion and consensus as to the ways in which biological indicators should best be used.
In other words, education is required of workers, employers, communities and regulatory authorities as to the meaning of the results obtained by biological monitoring so that no one is either unduly alarmed or complacent. There must be appropriate communication with the individual upon whom the test has been performed concerning the results and their interpretation. Further, whether or not the use of some indicators is experimental should be clearly conveyed to all participants.
See the chapter Ethical Issues for further discussion and the text of the Code. Biological monitoring can be carried out for only a limited number of environmental pollutants on account of the limited availability of appropriate reference data. This imposes important limitations on the use of biological monitoring in evaluating exposure. The World Health Organization WHO , for example, has proposed health-based reference values for lead, mercury, and cadmium only. These values are defined as levels in blood and urine not linked to any detectable adverse effect.
This is especially so in the case of biological monitoring data and it is therefore the responsibility of any laboratory undertaking analytical work on biological specimens from working populations to ensure the reliability, accuracy and precision of its results. This responsibility extends from providing suitable methods and guidance for specimen collection to ensuring that the results are returned to the health professional responsible for the care of the individual worker in a suitable form. All these activities are covered by the expression quality assurance. The central activity in a quality assurance programme is the control and maintenance of analytical accuracy and precision.
- Book Acute Exposure Guideline Levels For Selected Airborne Chemicals Volume 7.
- Investigating Internet Crimes: An Introduction to Solving Crimes in Cyberspace.
- Trimethylbenzenes - Wikipedia!
- Presentation Secrets Of Steve Jobs: How to Be Great in Front of Audience.
- Fault Diagnosis and Reconfiguration in Flight Control Systems.
- Occupational chemical agent compliance sampling guideline!
Biological monitoring laboratories have often developed in a clinical environment and have taken quality assurance techniques and philosophies from the discipline of clinical chemistry. Indeed, measurements of toxic chemicals and biological effect indicators in blood and urine are essentially no different from those made in clinical chemistry and in clinical pharmacology service laboratories found in any major hospital. A quality assurance programme for an individual analyst starts with the selection and establishment of a suitable method.
The next stage is the development of an internal quality control procedure to maintain precision; the laboratory needs then to satisfy itself of the accuracy of the analysis, and this may well involve external quality assessment see below. It is important to recognize however, that quality assurance includes more than these aspects of analytical quality control. There are several texts presenting analytical methods in biological monitoring.
Although these give useful guidance, much needs to be done by the individual analyst before data of a suitable quality can be produced. Central to any quality assurance programme is the production of a laboratory protocol that must specify in detail those parts of the method which have most bearing on its reliability, accuracy and precision.
Development of a suitable protocol is usually a time-consuming process. If a laboratory wishes to establish a new method, it is often most cost-effective to obtain from an existing laboratory a protocol that has proved its performance, for example, through validation in an established international quality assurance programme. Should the new laboratory be committed to a specific analytical technique, for example gas chromatography rather than high-performance liquid chromatography, it is often possible to identify a laboratory that has a good performance record and that uses the same analytical approach.
Laboratories can often be identified through journal articles or through organizers of various national quality assessment schemes. The quality of analytical results depends on the precision of the method achieved in practice, and this in turn depends on close adherence to a defined protocol. For example, for control of blood lead analyses, quality control samples are introduced into the run after every six or eight actual worker samples.
More stable analytical methods can be monitored with fewer quality control samples per run. The quality control samples for blood lead analysis are prepared from ml of blood human or bovine to which inorganic lead is added; individual aliquots are stored at low temperature Bullock, Smith and Whitehead Before each new batch is put into use, 20 aliquots are analysed in separate runs on different occasions to establish the mean result for this batch of quality control samples, as well as its standard deviation Whitehead These two figures are used to set up a Shewhart control chart figure The results from the analysis of the quality control samples included in subsequent runs are plotted on the chart.
The analyst then uses rules for acceptance or rejection of an analytical run depending on whether the results of these samples fall within two or three standard deviations SD of the mean. A sequence of rules, validated by computer modelling, has been suggested by Westgard et al. This approach to quality control is described in textbooks of clinical chemistry and a simple approach to the introduction of quality assurance is set forth in Whitehead It must be emphasized that these techniques of quality control depend on the preparation and analysis of quality control samples separately from the calibration samples that are used on each analytical occasion.
This approach can be adapted to a range of biological monitoring or biological effect monitoring assays.
Chapter 27 - Biological Monitoring
Batches of blood or urine samples can be prepared by addition of either the toxic material or the metabolite that is to be measured. Similarly, blood, serum, plasma, or urine can be aliquotted and stored deep-frozen or freeze-dried for measurement of enzymes or proteins. However, care has to be taken to avoid infective risk to the analyst from samples based on human blood.
Careful adherence to a well-defined protocol and to rules for acceptability is an essential first stage in a quality assurance programme. Any laboratory must be prepared to discuss its quality control and quality assessment performance with the health professionals using it and to investigate surprising or unusual findings. This is a difficult exercise for a laboratory to do on its own but can be achieved by taking part in a regular external quality assessment scheme.