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Dermal Exposure |
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A variety of
methods exist for estimating dermal exposure. Hand rinses, dermal/surface wipes,
and skin patches are some of the tools which can be used to determine the
effectiveness of gloves or the extent of the contamination in "clean"
work areas, such as break rooms and lunch rooms. Biological monitoring
results are also a very valuable means of determining if dermal exposure is a
major route of exposure. Presently, there are a limited number of guidance
values for chemicals measured in the body, that is the biological exposure
indices (BEIs) which are published by the
American
Conference of Governmental Industrial Hygienists (ACGIH).
In addition, there are many studies published in peer-reviewed literature which
report chemical exposure levels for workers in a variety of different
occupations and different industries.
- While "Skin" notation is an alert, the means to evaluate the magnitude of dermal exposure, its importance relative
to airborne exposure, and the effectiveness of preventive controls, are limited.
- Limits for biological response, called Biological Exposure Indices (BEIs)
by the ACGIH, have been set for 36 chemicals or chemical groups(2);
however, only 15 of these chemicals have a "Skin" notation, suggesting
that less than half of these BEIs are for chemicals that are significantly
absorbed through the skin. Biomonitoring methods are discussed at greater length
elsewhere.(27-28)
Monitoring and Evaluation Methods
Dermal exposure evaluation methods have been broadly categorized into direct
and indirect methods.
Direct
Direct means assessing what is deposited onto the skin.
- The most common direct method is the use of dermal dosimeters in the form of either patches(3-17)
or whole body suits.(3,12)
Other direct evaluation methods include skin washes and wipes,(3,10,11,13)
and the video detection of fluorescent tracers.(3,8,11,13,15)
Indirect
Indirect means estimating dermal dose either as attributable to some biologic indicator
that is actually measured or that which could potentially result from a
contaminant measured on an accessible surface.(3)
- Indirect methods refer primarily to measuring a biologic response such as cholinesterase activity in blood(5,6,14)
or urinary excretion(5-7,9,12,14,15),
but also include measuring surface contamination.(3,5,6,11,18-20)
Monitoring surfaces for contamination is an old method frequently used in the radiation health field where control is based on keeping exposure as low as
reasonably achievable. In comparison, chemical hazards allow exposures to define limits or thresholds of exposure. The problem is defining a relationship
between surface contamination and dose that would be used to set a surface contamination threshold. Most reviewers have found poor correlations between the
two.(11,18,19)
For instance, Caplan concluded there is no correlation between surface contamination levels as determined by wipe sampling and air concentration levels;
however, wipe sample levels can be useful in estimating dermal exposure if skin absorption data is available.(18) In the area of pesticide foliar residues, this relationship has been called a
"transfer coefficient."(3) There are currently no OSHA standards that
specify surface contamination criteria. However, several standards do require appropriate provision of personnel protective equipment
(PPE), housekeeping, decontamination, and related procedures to control surface contamination hazards.
Other Resources
-
Lead
Test Kits - Additional Observations. OSHA. Contains information on
lead test kits for tests on skin and other surfaces.
- Acrylamide Exposure During Chemical
Grouting Operations. OSHA Hazard Information Bulletin
(HIB), (1990, July 27). Alerts OSHA field personnel of the potential for significant
skin exposure to acrylamide during chemical grouting operations.
- Surface
Contamination. OSHA Safety and Health Topics Page. Addresses health effects, safety concerns, and control
and prevention techniques associated with surface contamination.
- What You Need to Know About Occupational Exposure to
Metalworking Fluids. US Department of Health and Human Services (DHHS), National Institute for Occupational Safety and
Health (NIOSH) Publication No. 98-116, (1998, March), 238
KB
PDF, 44 pages. Provides information about
the adverse health effects associated with occupational exposure
to metalworking fluids (MWFs) and MWF areosols.
- For additional information on monitoring techniques, see:
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