Exposure-Assessment Methods

The conmrittee evaluated the exposure assessment methods used by the Department of Defense (DOD) for air sampling. This section describes the re- 

Potential Health Risks to DOD Firing-Range Personnel 

The OSHA lead standard (29 CFR 1910.1025) includes requirements for performing monitoring to measure employee exposures and to determine the sources of lead emissions. The standard requires that the monitoring be performed without regard to respirators, that is, the protective factor of any worn respirator cannot be used in the determination of the exposure of an employee (43 Fed. Reg. 52925 [1978]). 

The lead standard requires an initial assessment of lead exposures and requires that air samphng be performed or that air sampling performed in the previous 12 months be used to make the initial determination of employee exposure. The standard indicates that the air monitoring ean be eonducted on a sample of the exposed woikers who are beheved to have the highest exposures. Any additional monitoring is contingent on the findings of the initial assessment 

If the results of the initial assessment are negative (airborne concentrations were all below the action level of 30 pg/m ), no further monitoring is required. The results of the initial assessment need to be documented in writing. Further monitoring needs to be conducted only if a change in the process, controls, or personnel could result in an increased exposure to lead. 

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Collectively, the data from Table 7 and Figures 1 through 3 lead to the conclusion that concurrent biomonitoring and passive dosimetry techniques can be achieved and are not divergent worker exposure assessment methods. The correlation between exposure levels measured by these methods is quite good. 

Many other OECD activities on hazard/risk assessment are undertaken within programs such as Existing Chemicals, New Chemicals, and Pesticides and Biocides, which deal with specific types of chemicals. The work on exposure assessment methods is undertaken by the Task Force on Environmental Exposure Assessment, consisting of experts. Most of the outcome of this work is published in the Series on Testing and Assessment or in Emission Scenario Documents, which are available at the OECD Web site (OECD 2006a). 

Seal, A. B. Bise, C. J. 2002. Case study using task-based, noise-exposure assessment methods to evaluate miner noise hazards. Mining Engineering, 54, 44-48. 

OECD (1989) Compendium of environmental exposure assessment methods for chemicals. Paris, Organisation for Economic Co-operation and Development (Environmental Monograph No. 27). 

Table 7.1 Exposure assessment methods in different epidemiological study designs... 

Before examining each of these exposure assessment methods in more detail, it is important to consider the consequences of imprecise or biased exposure assessment on the risk estimates made in an epidemiological study. 

Specific chemical exposures and exposure assessment methods relating to studies in the alumina and primary aluminium industry have been reviewed (14). In aluminium smelting, exposure to fluorides, coal tar pitch volatiles, and sulfur dioxide has tended to abate in recent years, but there is insufficient information about other exposures. Published epidemiological studies and quantitative exposure data for bauxite mining and alumina refining are virtually non-existent. Determination of possible exposure-response relations for this part of the industry through improved exposure assessment methods should be the focus of future studies. 

Therefore, to estimate or measure aggregate exposures, relevant and reliable data are required. Further, aggregate exposure assessment methods and modeling tools are needed that more accurately reflect real-life situations (in contrast to methods and models that are based on very conservative assumptions and may lead to less realistic and sometimes gross overestimates of exposure). 

Longitudinal exposure assessment methods and measurements have emerged to address temporal and spatial aspects of aggregate exposures. Longitudinal... 

Screening-level or initial tier predictive exposure assessment methods typically involve the use of an algebraic equation that expresses exposure or absorbed dose as a function of the concentration of a chemical in relevant media (e.g., air, food, and water) and other important factors. For example, inhalation exposure (Emh) to an airborne chemical can be estimated using some form of the following equation ... 

Kolanz ME, Madl AK, Kelsh MA, Kent MS, Kalmes RM, Paustenbach DJ. A comparison and critique of historical and current exposure assessment method for beryllium Implications for evaluating risk of chronic beryllium disease. Appl Occup Environ Hyg 2001 6 593-614. 

Carrieri, M., Bonfiglio, E., Scapellato, M. L., Macca, 1., Tranfo, G., Faranda, P, Pad, E., and Bartolucci, G. B. (2006). Comparison of exposure assessment methods in occupational exposure to benzene in gasoline filling-station attendants. Toxicol Lett 162, 146-152. 

Drummond, I., Murray, N., Armstrong, T., Schnatts, A. R., and Lewis, R. J. (2006). Exposure assessment methods for a study of mortality and cancer morbidity in relation to specific petroleum industry exposures. J Occup Environ Hyg 3, 513-520. 

At the beginning of this paper, an indirect exposure assessment method was described that utilizes microenvironment UFP concentrations and time-activity patterns to assess population exposure. Although this approach is known to underestimate the extreme exposures that may exist within a population, it may... 

OECD (1989a) Compendium of Environmental Exposure Assessment Methods for Chemicals, Environment Monograph No. 27, OECD, Paris. 

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