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F.
R. Hall, L. M. Kirchner and R.A.J. Taylor
NIOSH Education and Information Division
Pesticides
and other hazardous chemicals in the environment are of growing
concern as to the "real" risk to an expanding Ohio population.
Exposure assessment is a vital component of the quantitative
risk assessment procedures utilized to produce pesticide regulatory
decisions. The EPA has published general guidelines for exposure
assessments. LPCAT is currently evaluating the capture efficiencies
of passive dosimeters (as part of a USEPA grant), and has
developed a wind tunnel model to predict exposure related
to pesticide drift to humans and water in the immediate vicinity.
Meteorological conditions, exposure duration, type of exposure
(activity pattern by species), and active ingredient (AI)
formulation and application technologies are all important
in establishing real risk (hazard) projections or risk reduction
strategies. Further confounding the issue are the differential
capture efficiencies expressed by various dosimeters, human
skin, and protective clothing, as well as non-target species.
Neglect of these differences can mislead the risk assessment
resolution.
A novel
system has been devised for examining the relative capture
efficiencies of dosimeters. Capture efficiency is defined
as the mass of material captured by an object (dosimeter)
placed in an air stream relative to the mass of material that
would pass through the targets projected area, had it not
been there. The system is comprised of the following components:
wind tunnel, fluorescent tracer solution, an atomizer and
the capture efficiency test device. Data are presented on
the standardization of the model and examples of capture efficiencies
of several commonly utilized dosimeters. The proposed system
is flexible in terms of duration of exposure, drop-sizes used,
and amount of material introduced to the device. Thus, in
addition to the wind tunnel laboratory studies, the system
may be used to monitor exposure hazards in an array of real-world
application scenarios. The potential utilization of such knowledge
and monitoring technology is expected to be incorporated into
the NIOSH supported study "Ohio Farm Family Health and Hazard
Surveillance Program", Jay Wilkins (PI). Exposure of farm
families to pesticides will be one of the safety hazards monitored
in the Ohio study. This model can thus be validated as a tool
to quantify off-site exposure to pesticides. The data should
allow a better understanding and, hence, characterization
of potential chemical risks via various routes of exposure
for farm families.
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NASD Review: 04/2002
This
research abstract was extracted from a portion of the proceedings
of "Agricultural Safety and Health: Detection, Prevention and
Intervention," a conference presented by the Ohio State University
and the Ohio Department of Health, sponsored by the Centers
for Disease Control/National Institute for Occupational Safety
and Health.
The
authors noted above are from: All from the Laboratory for
Pest Control Application Technology, The Ohio State University,
Wooster, OH.
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