Exposure measurements

In all of the process operations except venting and flaring, exposure is related to worker activity, and to some extent is dependent on worker behavior and the work practices appHed. The distinction between those exposures that are impacted by worker behavior and those that, barring the use of respirators, are not is important. The types of control methods to be appHed and the methods of exposure measurement to be used are influenced by this difference. 

Proximity to Breathing Zone. Whereas all exposure measurement methods attempt to sample from air that is likely to be inhaled, some methods do so better than others. A sampler fixed some distance away from a breathing area is not usually accurate in measuring exposure. Even using mobile samplers that move with the worker, the few centimeters in distance from the nose and mouth to the position of the sampler, has been found to make a difference. 

L. Fishbeia and 1. K. O Neill, eds.. Environmental Carcinogens Methods of Analysis and Exposure Measurement, Vol. 10, International Agency for Research on Cancer, Lyon, France, 1988, Chapts. 7—12. 

Exposure to sulfur dioxide in the ambient air has been associated with reduced lung function, increased incidence of respiratory symptoms and diseases, irritation of the eyes, nose, and throat, and premature mortality. Children, the elderly, and those already suffering from respiratory ailments, such as asthmatics, are especially at risk. Health impacts appear to be linked especially to brief exposures to ambient concentrations above 1,000 ixg/in (acute exposures measured over 10 minutes). Some epidemiologic studies, however, have shown an association between relatively low annual mean levels and excess mortality. It is not clear whether long-... 

Capture efficiency measurements may be used to evaluate the function of a canopy hood (see Section 10.5). Capture velocity is not a feasible evaluation tool, since a canopy hood does not generate an air velocity close to the source. It is also possible to use exposure measurements for workers outside the plume area. Since most hot processes generate visible contaminants, visual inspection of the flow, especially around hood edges, might provide a qualitative evaluation. Many contaminants could however be invisible when diluted and smoke generators (Section 10.5) may be necessary to find leakages (temporary or permanent) around the hood edges. 

C.P. Weisskopf and J.N. Seiber, New approaches to the analysis of organophosphate metabolites in the urine of field workers, in ACS Symposium Series Biological Monitoring for Pesticide Exposure Measurement, Estimation, and Risk Reduction, eds. R.G.M. Wang, C.A. Franklin, R.C. Honeycutt, and J.C. Reinert, American Chemical Society, Washington, DC, pp. 206-214 (1989). 

Kauppinen T, Teschke K, Savela A, et al. 1997. International data base of exposure measurements in the pulp, paper and paper products industries. Int Arch Occup Environ Health 70 119-127. 

Nigg and Stamper (1983) conducted potential exposure and actual exposure measurements during three weekdays over three consecutive weeks for applicators and mixer-loaders, one week using normal work clothes, the second week disposable coveralls in addition to their work clothes, and the third week disposable coveralls and NIOSH-approved respirators. In conjunction, urinary excretion of a metabolite of the active ingredient was... 

Dubelman, S., Lauer, R., Arras, D.D., and Adams, S.A. (1982) Operator exposure measurements during application of the herbicide diallate, /. Agric. Food. Chem., 30 528-532. 

A spin-off of all of these task forces has been the open discussions that have led to improved design considerations and effective use of resources in the conduct of field exposure studies. These task forces have evaluated a variety of exposure measuring techniques, developed study designs for conducting studies, and performed field studies in a uniform and efficient manner. The task force protocols and designs have become models for the industry, having received valuable input and approval from the regulatory community. 

Characterization of Environmental Exposure Measuring Versus Modeling... 

Rock, R.L., D.B. Lovett, and S.C. Nelson, Radon-daughter Exposure Measurement with Track Etch Films, Health Physics 16 617-621 (1969). 

Acrylonitrile is rapidly distributed throughout the body after inhalation exposure. Measurable amounts of acrylonitrile derived radiolabel were present in the brain, stomach, liver, kidney, lung and blood within 1 hour of initiation of exposure (Pilon et al. 1988b). 

Blood counts are also used to determine toxic exposures. Measurements of the red and white blood cells, hemoglobin content, and platelet count are performed easily and inexpensively. However, blood counts are frequently insensitive to toxic exposure marked changes are seen only after substantial exposure and damage. 

Androstadienone, 112, 113, 114, 122 exposure, measurable effects of, 116 reaction of homo and heterosexual males to, 123... 

Exposure. Measurement of endrin and its metabolites can be useful indicators of exposure. Since endrin is cleared from the blood rapidly, such measurements are suitable only for recent exposures. Additional studies are needed to determine the usefulness of metabolites in urine as biomarkers of exposure in humans. A quantitative relationship between the urinary concentration of anti-12-hydroxyendrin and the dose of endrin should be clarified. 

Exposure. Measurement of total phenol in the urine is the most useful biomarker following inhalation exposure to phenol (ACGIH 1991). The test is nonspecific and should not be used when workers are exposed to benzene, to household products, or to medications containing phenol. Dermal exposure may also result in overestimation of inhalation exposure. In persons not exposed to phenol or benzene, the total phenol concentration in the urine does not exceed 20 mg/L and is usually <10 mg/L (ACGIH 1991). Phenol can also be measured in the urine after oral exposure, although a dose-response relationship between oral exposure to phenol and phenol in the urine has not been established. Benzene metabolism yields not only phenol, 1,4-dihydroxybenzene, and their sulfates and glucuronides, but also the benzene-... 

Wallace L, Zweidinger R, Erickson M, Cooper S, et al. 1982. Monitoring individual exposure. Measurements of volatile organic compounds in breathing-zone air, drinking water, and exhaled breath. Environ Int 8 269-282. 

A case report of oral exposure to technical-grade chlordane reported neurological effects including irritability, salivation, dizziness, muscle tremors, and convulsions (Dadey and Kammer 1953). However, exposure measurements were not provided in the report, and technical-grade chlordane contains varying amounts of heptachlor. The effects cannot be said to have resulted from exposure to heptachlor only. 

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