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Exposure
assessment is a multidisciplinary field central to deciding whether
and how to use resources for reducing workplace exposures, and to defining
exposure-response relationships in epidemiologic studies. Rapid, inexpensive
measurement tools and improved data analysis methods are needed for
the collection of adequate exposure data and for effective intervention.
These advancements will lead to (1) better identification of at-risk
workers, (2) better identification of the most cost-effective control
and intervention strategies, (3) better understanding of exposure-response
relationships, and (4) improved baseline data for standard setting and
risk assessment.
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Importance |
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Exposure assessment is a rapidly evolving, multidisciplinary research activity. Its purpose is to provide environmental data with which to decide whether and how to reduce workplace exposures, and to define exposure-response relationships in epidemiologic studies. Imprecise estimation of exposure is often cited as the major limitation in epidemiologic research, hampering the ability to detect environmental causes of disease. Improved exposure assessments will lead to more precise characterization of exposure-response relationships for chemical, physical, and biological agents, and to more appropriate exposure limits for hazardous agents. Employers often have insufficient exposure data to guide selection of exposure controls or to justify the necessary financial investments. Moreover, accurate exposure data are equally important in evaluating the effectiveness of those controls after their implementation. The lack of cost-effective methods and measurement tools that can be used by nonspecialists has been a major obstacle to collecting adequate exposure data and instituting effective controls. In the past 15
to 20 years, the scope of occupational exposure assessment has broadened
considerably as a result of changes in technology and increased attention
to nonindustrial work settings. At least three major gaps in current
methods will drive development of exposure assessment methods in the
next decade: (1) the lack of sufficiently precise exposure assessments
to support accurate epidemiologic studies in the complex environments
of today's workplaces, (2) the lack of practical measurement techniques
that can be applied at reasonable cost in many workplaces where hazards
may exist, and (3) the lack of validated methods for measuring relevant
exposure and total dose data directly from biological samples obtained
by relatively noninvasive techniques. |
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Research Opportunities |
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Researchers from a variety of fields (including industrial hygiene, chemistry, physics, molecular biology, epidemiology, and medicine) will pursue a variety of research paths to develop exposure assessment methods that are more precise, low-cost and easy to use, and more biologically based. For example, computer models may be developed to extrapolate information from historical data of limited exposure measurements to apply to large study populations, and to incorporate short-duration but high-intensity exposures such as leaks or spills into the models. Easy-to-use, direct-reading instruments and test kits will be developed to measure exposures rapidly and inexpensively in a variety of workplaces for routine monitoring, evaluating the success of control technologies, and providing data for research studies. Technological advances will permit measurement of low concentration of chemicals and biomarkers in biological specimens such as blood, urine, saliva and sweat, and research will link these concentrations to internal dose at the target organs. Laboratory analytical methods will be designed for inexpensively measuring numerous chemicals in a single sample. Research into improved measurement and interpretation of biomarkers will allow a more selective evaluation of the effects of structurally similar chemicals. Finally, research into exposure survey design and exposure data analysis methods will lead to more meaningful data for health risk assessments. Such research will
result in more clearly defined exposure assessment methods and strategies
that can be recommended for wider adoption. More consistent use of well-designed
exposure assessment methods will promote comparability among exposure
data sets and enhance the utility of the data for a broad range of prevention
activities. During the next 10 years, improved exposure assessment methods
will lead to better identification of at-risk workers, better identification
of the most cost-effective control and intervention strategies, better
understanding of exposure-response relationships, and improved baseline
data for standard setting and risk assessment, all of which are central
to improving occupational safety and health. |
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Current Activities |
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The Exposure Assessment Methods Team is composed of 14 members representing various disciplines (e.g., chemistry, biology, industrial hygiene, occupational health nursing, toxicology, and epidemiology) from government, academia, labor, and industry. The team is involved in symposia with the American Conference of Government Industrial Hygienists, National Institute of Environmental Health Sciences/National Toxicology Program, and the International Symposium on Occupational Exposure Data Bases and Their Application in the Next Millennium. The team is in the process of developing a white paper describing research that addresses key exposure assessment issues such as field study design, monitoring methods development, and toxicology research, along with needs in education and publications relative to exposure assessment.
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