United States Health Effects Research EPA-600/2-80-180
Environmental Protection Laboratory August 1980
Agency Research Triangle Park NC 27711
Research and Development
&EPA Users Guide
Protocol for Assessment
of Human Exposure to
Airborne Pesticides
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7 Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental degradation from point and non-point sources of pollution. This work
provides the new or improved technology required for the control and treatment
of pollution sources to meet environmental quality standards.
EPA REVIEW NOTICE
This report has been reviewed by the U.S. Environmental Protection Agency, and
approved for publication. Approval does not signify that the contents necessarily
reflect the views and policy of the Agency, nor does mention of trade names or
commercial products constitute endorsement or recommendation for use.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/2-80-180
August 1980
PROTOCOL FOR ASSESSMENT OF HUMAN
EXPOSURE TO AIRBORNE PESTICIDES
by
Robert G. Lewis, Merrill D. Jackson and Kathryn E. MacLeod
Environmental Toxicology Division
Health Effects Research Laboratory
Research Triangle Park, North Carolina 27711
HEALTH EFFECT RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
RESEARCH TRIANGLE PARK, NORTH CAROLINA 27711
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DISCLAIMER
This report has been reviewed by the Health Effects Research
Laboratory, U.S. Environmental Protection Agency, and approved for
publication. Approval does not signify that the contents necessarily
reflect the views and policies of the U.S. Environmental Protection
Agency, nor does mention of trade names or commercial products
constitute endorsement or recommendation for use.
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FOREWORD
The many benefits of our modern, developing, industrial society are
accompanied by certain hazards. Careful assessment of the relative risk
of existing and new man-made environmental hazards is necessary for the
establishment of sound regulatory policy. These regulations serve to
enhance the quality of our environment in order to promote the public
health and welfare and the productive capacity of our Nation's population.
The Health Effects Research Laboratory, Research Triangle Park,
conducts a coordinated environmental health research program in toxicology,
epidemiology, and clinical studies using human volunteer subjects.
These studies address problems in air pollution, non-ionizing radiation,
environmental carcinogenesis and the toxicology of pesticides as well as
other chemical pollutants. The Laboratory participates in the development
and revision of air quality criteria documents on pollutants for which
national ambient air quality standards exist or are proposed, provides
the data for registration of new pesticides or proposed suspension of
those already in use, conducts research on hazardous and toxic materials,
and is primarily responsible for providing the health basis for non-
ionizing radiation standards. Direct support to the regulatory function
of the Agency is provided in the form of expert testimony and prepara-
tion of affidavits as well as expert advice to the Administrator to
assure the adequacy of health care and surveillance of persons having
suffered imminent and substantial endangerment of their health.
One mission of the Environmental Protection Agency is to monitor
the air for pesticides. Pursuant to this mission, this project was
111
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undertaken by HERL to establish uniform methodology for obtaining adequate
data on the contamination of the atmosphere by pesticides. This will
give EPA the ability to define the threat of atmospheric pesticidal
pollutants and lead to the determination of their effect on the general
population and the ecosystem.
F. G. Hueter, Ph.D.
Director
Health Effects Research Laboratory
iv
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ABSTRACT
The Environmental Protection Agency has been given the authority
for monitoring the air for pesticides. This protocol reports on methodology
that has been developed to assure that the air samples collected will
give adequate information on the exposure of the general population to
pesticidal air pollutants.
Descriptions are given of pumps, sorbents, calibration methods, and
preparations necessary for accurate data collections. The determination
of sampling efficiencies and respiratory exposure is also discussed.
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CONTENTS
Page
Di scl aimer 11
Foreword i ii
Abstract v
List of Figures vii
List of Tables viii
Section I: Introduction 1
Section II: Ambient Air Sampling 2
1. Description of Ambient Air Samplers 2
2. Description of Sampling Modules 5
3. Calibration of EPA/SURC Air Sampler 10
4. Description of Sampling Media (Sorbents) 13
5. Preparation of Sampling Media 15
6. Determination of Sampling Efficiencies 17
7. Collection of Air Samples 20
8. Results and Discussion 21
Section III: Source Sampling 22
1. High Volume Source Samples 23
2. Low Volume Indoor Source Samplers 23
Section IV: Workplace Air-Personnel Monitoring 37
1. Air Sampling Devices 38
2. Preparation and Handling of Samples 39
3. Sampling Duration 40
4. Estimation of Inspired Quantities 41
Section V: References 45
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LIST OF FIGURES
No. Page
1. EPA/SURC high volume ambient air sampler for pesticides,
PCBs and other organic compounds 4
2. The SURC sampl ing module 6
3. EPA/SWRI high-volume sampling module 8
4. Device for calibration of air sampler 11
5. Calibration plot for EPA/SURC sampler 14
6. Dual sorbent vapor trap 16
7. A high-volume air sampler developed for the U.S. Army by
Environmental Research Corporation (ERCO) 24
8. The DuPont constant flow sampling pump 26
9. MSA personal sampling pump and three collection modules 27
10. Calibration unit for the MSA personal sampling pumps 31
11. Calibration unit for DuPont personal sampling pumps 32
12. Midget impinger used for collection efficiency studies 35
vn
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LIST OF TABLES
No. Page
1. Normal Respiratory Rates for Humans 42
2. Subjective Estimations of Respiratory Rates for Pesticide
Workers 43
vm
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I. INTRODUCTION
Pesticides in air represent an important class of toxic pollutants,
which may have chronic deleterious effects on human health and
ecological balance. In 1963, the President's Science Advisory
Committee recommended that the air be continuously monitored for
pesticides. The authority for such monitoring in the U.S. has been
granted to the Environmental Protection Agency under the Clean Air
Act as amended in December 1970, and the Federal Insecticide,
Fungicide, and Rodenticide Act as amended in 1972.
Presently, there are only limited data concerning the contamination
of the atmosphere by pesticides, especially in urban areas. Informa-
tion relating to transport or ambient trends is even less available.
Such information must be obtained before total air quality can be
defined and before the threat of atmospheric pesticidal pollutants
to the general populace and the ecosystem can be determined.
The determination of pesticides in the ambient air is a formidable
task. There are hundreds of pesticides registered for use in the
U.S., many of which are potential air pollutants. These pesticides
may exist in air as vapors, aerosols, or adsorbed on suspended
particulate matter; thus, their collection is complicated. Pesticides
are usually present in air at levels far lower than those found in
crop residues for which most methods of analysis are designed;
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hence, their detection is difficult. Metabolites and degradation
products of pesticides, which are sometimes considerably more toxic
than the parent pesticide, are, of course, at even lower atmospheric
concentrations.
Most of the existing data concerning the nature and degree of
contamination of the ambient atmosphere by pesticides was collected
over the period from 1970 to 1972 by the EPA. The sampling method
utilized was based on impingement in ethylene glycol, which was
expensive and cumbersome to use and did not provide an adequate
sample size to permit subnanogram per cubic meter detectabilities
for most pesticides. During the past several years, EPA has devel-
oped a high volume air sampler that is believed to better serve the
needs for pesticide ambient air monitoring. This sampling device
and others for indoor air sampling, crop re-entry monitoring, and
work-place and personnel monitoring are described.
II. AMBIENT AIR SAMPLING:
1. Descriptions of Ambient Air Samplers
For ambient (uncontaminated) air, sufficiently large samples
must be taken to permit detection and measurement at ultra-
3 3
trace levels (pg/m to ng/m ). Such sampling should be per-
formed over an entire diurnal cycle if results are to be
-------
representative of the average quantities of the substances
normally present in the atmosphere.
234
a. The sampler developed by EPA ' ' has been referred to as
the EPA/SURC sampler (Fig. 1), since it is similar to a
high volume pesticide air sampler designed for EPA by
Syracuse University Research Corporation. The device
uses a Hi-Vol pump and shelter, and draws air through a
glass fiber filter (to collect particulate matter) and a
solid sorbent cartridge (to trap vapors) at sampling
rates up to 280 liters/minute. The sampler can be used
with a wide variety of sorbents in a manner that permits
their continual re-use. It is designed for low cost and
simple operation. The sampler has been demonstrated to
efficiently collect a number of organochlorine and organo-
phosphate pesticides, and it is presently being evaluated
for carbamates.
A standard aluminum Hi-Vol sampler housing is modified by
replacing the sheet aluminum support plate with one that
is 9 mm thick. A second support plate is added approx-
imately 25 cm from the bottom of the sampler to lend
strength. The top plate forms the support for the blower
unit and pesticide collection module as well as the
necessary plumbing.
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RAIN SHELTER
Figure 1. EPA/SURC high volume ambient air sampler for pesticides, PCBs
and other organic compounds.
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All parts and how they are connected are shown in Figure
1. A variable power transformer is provided to adjust
the vacuum pulled by changing the motor speed. This
prolongs the life of the motor. The flow is measured by
two devices: a Dickson recorder (The Dickson Company,
Minicorder, Design 1), which keeps a continuous record of
the flow versus time, and a venturi (Barco Model BR-12402-
08-31) - Magnehelic gauge (Dwyer Instruments Model 2100),
used to set the flow rate of the sampler when in operation
The exhaust duct is required to stop recycling of the
air.
b. PCBs (polychlorinated biphenyls) have been collected on
3
polyurethane foam by sampling 3.4-200 m of air with
Bendix Hurricane dual speed pumps (National Environmental
Instruments, Inc., Warwick, RI 02888, Cat. No. 16003) at
flow rates of 0.1-0.5 m /minute.
2. Descriptions of the Sampling Modules
a. The SURC sampling module is shown assembled (a) and
exploded (b) in Figure 2. The basic module consists of a
4-inch (i.d.) by 2-inch (i.d.) (10 cm x 5 cm) glass
process pipe reducer (Kimax 6650, size 4, or equivalent -
Part 1 in Fig. 2). This part is approximately 18 cm
long. Standard glass pipe fittings (parts 2 and 3) are
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SORBENT
SUPPORT SCRFEN
FILTER SUPPOR1
SCREEN
10
30 ao
SCALE, cm
Figure 2. The SURC sampling module, assembled (a) and disassembled (b). Part 1 is a 4-in x
2-in glass process pipe reducer. Parts 2 and 3 are stainless steel pipe fittings with
Teflon inserts. Part 4 is a 5.5-cm x 7.6-cm polyurethane foam cylinder and Part 5 is a
Gelman Type A glass fiber filter (it is installed under Part 2).
-------
used on each end (2-inch and 4-inch connectors). At the
smaller end, a stainless steel screen (10 openings/cm) is
cut to fit and installed to hold the polyurethane foam
plug (4) or other sorbent in place. A piece of stainless
steel screen (4 openings/cm) is cut and installed at the
larger end. This holds either the glass fiber filter (5)
in normal operation or wool felt filter for controlled
introduction of vapors of the test compounds. When foam
is used as the sorbent, the larger opening screen may be
used on both ends. The lower pipe fitting (part 3) is
tightened down on a 2 inch stainless steel flange.
b. EPA - SWRI Sampling System - The sampling system was
developed by Southwest Research Institute and was sub-
stantially modified and improved by EPA to allow use of a
variety of sorbent types (Fig. 3). This module is shown
in place on the sampler in Figure 1. The same sampler
described under Item 1 above is used. There are two
parts to the sampling system: the sampling module or
cartridge and the air-tight cartridge holder.
Sampling cartridge - Borosilicate glass tubing (65 mm,
OD) is cut to 125 mm in length. An indentation is formed
20 mm from one end (bottom) to provide a rim to retain a
25 mesh or larger stainless steel screen to hold the
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CD
Figure 3. EPA/SWRI high-volume sampling module, (a) Sampling cartridge; (b) assembled
module containing cartridge and prefilter; (c) silicone rubber gaskets; (d) glass fiber
prefilter; (e) support screen; (f) silicone rubber "0"-ring. Part I - Cartridge receptacle.
Part 2 - Prefilter adapter. Part 3 -Filter support screen. Part 4 - Filter retaining ring.
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sorbent. The cartridge can then hold a polyurethane foam
plug, porous (macroreticular) beads or other solid sorbents,
or liquid coated beads.
This entire cartridge can be placed in a Soxhlet ex-
tractor for removal of substances collected in air.
Vacuum drying at 30°C to 40°C restores the sorbent for
reuse within several hours. The cartridge is shown in
Figure 3 (Part a).
Cartridge holder - The basic cartridge holder is shown
both assembled (b) and disassembled in Figure 3. Part 2
screws down on to Part 1 and silicone rubber (GC septum
sheet stock, Supelco Catalog No. 2-04626) gaskets (c) on
both ends form an air-tight seal. Part 3, a 10-mesh
stainless steel screen, holds either the glass fiber
filter (d) or the felt pad. Part 4 holds the filter or
pad in place. Part 1 is tapped and threaded on the
bottom to attach to the 1/2 inch NPT inlet of the high-
volume air pumping system shown in Figure 1.
c. Bendix Hurricane Pump filter holder - The standard 10 cm
filter holder is modified by attaching a cylindrical
chamber, 25 cm long x 5 cm i.d., behind the filter holder
with epoxy cement. Place two foam plugs, 5.5 cm diameter x
8 cm thick, in the chamber and a 10 cm diameter glass
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fiber filter in front of them in the filter holder.
Connect the sampler to the Bendix pump by a 7.6 meter
length of Flexaust® CWC hose.
3. Calibration of Air Sampler
Refer to Figure 1 for a schematic diagram of the sampler. The
needle valve is for test purposes only and is not used in
normal operation. The red tap of the venturi goes to the high
pressure side, and the green tap goes to the low pressure side
of the Magnehelic gauge. A gasket goes between each floor
flange and the base, and between the Hi-Vol housing and the
base. Check these for leaks before starting. Make the modifi-
cation to the motor housing shown in Figure 4.
Calibration procedure:
a. Attach the calibration venturi in place of the sampling
module and tighten securely.
b. Connect a 4"-0-4" slack tube Hg manometer to the taps of
the calibrated venturi. Make sure the manometer is
zeroed and level. Mark this manometer to indicate that
it is to be used only with the audit venturi.
10
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DETAIL'A': CUT OFF ENDS
OF 3/8 in NPT PIPE COUPLING
STEEL WASHER
r \
END OF 3/8 in NPT
PIPE COUPLING
(SEE DETAIL'A')
RUBBER GROMMET
(SPLIT IN HALF)
HI-VOL MOTOR HOUSING
3/8 in NPT NIPPLE
V I
STEEL WASHER
RUBBER GROMMET
(SPLIT IN HALF)
END OF 3/8 in NPT
PIPE COUPLING
(SEE DETAIL'A')
Figure 4. Device for calibration of air sampler.
11
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c. Zero the Dickson recorder (tap the face) and the Magnehelic
gauge.
d. Turn the power transformer to 100 volts and turn the
switch to ON. Allow the Hi-Vol motor to warm up for
several minutes before readings are taken.
e. Record the ambient temperature in °C on the data form.
f. Record the barometric pressure in mm Hg.
g. Open the ball valve fully (the pointer on either zero
mark). Record the audit venturi DP, the Dickson reading,
and the Magnehelic reading.
h. Close the indicator valve slightly until the Magnehelic
drops approximately 5 inches (13 cm) and record a new set
of readings.
i. Repeat step (h) until five spaced sets of readings are
obtained.
j. Remove the calibrated venturi.
12
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k. Prepare a calibration chart of flow rate versus meter
readings as shown in Figure 5.
To calibrate Bendix high volume pumps, force the exhaust
air through a restricting orifice (supplied with the
pump) and measure the resulting back pressure by a gauge
placed directly ahead of the orifice. A gauge calibrated
by the manufacturer to read directly in ft /minute air
flow is available.
4. Descriptions of Sampling Media (Sorbents)
Two types of sampling media are recommended for use with the
EPA/SURC sampler: polyurethane foams and granular solid
sorbents. Foams may be used separately or in combination with
granular solids in either sampling module described previously.
With the EPA/SURC module, the sorbent may be extracted and
reused (after drying) without unloading the cartridge.
Polyurethane foam (PUF) - Use polyether-type polyurethane foam
3
[density No. 3014 (0.0225 grams/cm ), or equivalent]. This is
the type of foam generally used for furniture upholstery,
pillows, and mattresses. It is white and yellows on exposure
to light. Use 7.6 cm (3 in.) sheet stock and cut from it
cylindrical plugs that fit under slight compression in the
glass cartridge or module, supported by the wire screen. For
13
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o
10
I I I I I I
• VENTURI
Q DICKSON
I I
10
20 30 40 50
MAGNEHELIC OR DICKSON READING
60
70
80
Figure 5. Calibration plot for EPA/SURC sampler.
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the SURC module, the plugs should be 5.5 cm in diameter and
fitted into the lower 5 cm (i.d.) chamber of the module. For
the EPA/SWRI cartridge, the plug diameter should be 6.0 cm.
Granular solids - Porous (macroreticular) chromatography
@
sorbents are recommended. Examples are Chromosorb 102, 20-
(R)
to 40-mesh (Johns-Manvil le, Denver, CO); Porapak R, 50- to
80-mesh (Waters Associates, Mil ford, MA); Amberlite® XAD-2,
16- to 50-mesh (Rohm and Haas Co., Philadelphia, PA); Tenax®-GC,
60- to 80-mesh (Enka N.V., The Netherlands); and Florisil®
PR-grade, 16- to 30-mesh (Floridin, Pittsburgh, PA). Pore
sizes and mesh sizes must be selected to permit air flow rates
3
of at least 200 liters/minute. Approximately 25 cm of the
sorbent is recommended. The granular solids may be "sandwiched"
between two layers of polyurethane foam (a 60 mm diameter x 50
mm foam plug on top and a 60 mm diameter x 25 mm PDF plug on
the botton) to prevent loss during sampling and extraction
(Figure 6).
5. Preparation of Sampling Media
a. Prepare sorbent for initial cleanup before use. For
foam, cut an appropriate size cylindrical plug with a
cutting tool and place in a Soxhlet extractor. For
granular or porous polymeric solids, add to pre-extracted
Soxhlet thimble and place in the extractor.
15
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65 mm x 125 mm
GLASS
CYLINDER
SUPPORT .-
A .». H n .M. X-V/^ A *^\ *-V ,-S. X% ^N
J ' aT C
-v
1
50 mm PUF
' PLUG
25cm3 GRANULAR
SORBENT
25 mm PUF
PLUG
Figure 6. Dual sorbent vapor trap.
16
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b. Extract with 5% diethyl ether in rrhexane (glass distilled,
pesticide quality or equivalent) or other appropriate
solvent(s) for 14-24 hours at ca 4 cycles/hour.
NOTE: To determine the blank value of each plug,
extract twice for periods of 7-12 hours;
concentrate the second solvent, pass
through an alumina column, and analyze by
GC.
c. Dry the sorbent under vacuum at 75°C.
d. Place the sorbent into glass sampling modules. For loose
solids, the appropriate volume (e.g., 25 ml) should be
measured and the corresponding weight recorded.
e. Place the sampling module in a sealed container or wrap
in hexane-rinsed aluminum foil until ready for use.
6. Determination of Sampling Efficiencies for Specific Pesticides
a. Pesticide Retention Efficiency
No air sampler may be used for assessing of atmospheric
concentrations of any compound without first determining
the efficiency of the sampler to trap and retain the
17
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compound. Determine retention efficiencies by multiple
injections of microliter volumes of the pesticide of
interest in ji-hexane directly into the sorbent trap.
After a one hour drying period, place the fortified trap
in front of a second trap in the sampling system. Pump
ambient air through the train for the length of time and
volume to be used in the sampling (i.e., for the high
volume system, 24 hours at 200-250 liters/minute) to
determine breakthrough to the second trap. Exclude
airborne particulate matter by means of a glass fiber
prefiIter.
b. Pesticide Collection Efficiency
Determine collection efficiencies by vaporizing individual
compounds or mixtures into the intake of the air sampler
under study. Replace the glass fiber prefiIter with a
2
pre-extracted wool felt filter (weight 14.9 rug/cm ,
thickness 0.6 mm), which is then fortified with the
pesticide of interest before pulling ambient air through
it and, subsequently, the vapor trap(s). Add dropwise
hexane solutions containing microgram amounts of the test
compounds to the filter in amounts of 1 ml or less, and
evaporate the solvent before the filter is attached to
the sampling module. After 24 hours of air flow, analyze
18
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the filter and sorbent trap(s) individually. Make at
least one blank determination with unfortified filters
simultaneously to correct for airborne interferences and
possible contamination or losses from the analytical
methodology.
Perform these tests outdoors with unaltered ambient air
(in a rural, nonindustrialized area) whenever possible.
When required, filter the intake air through a PDF trap
to remove interfering contaminants.
All pesticidal compounds used for establishing sampling
efficiency should be of the highest purities obtainable.
Purities should be checked before use. All solvents
should be pesticide quality or equivalent.
Conduct at least six independent trials for each test
compound in order to provide statistical data. Accept-
able standard deviation values will depend on the nature
of the pesticide. For example, for the less volatile,
more chemically stable and more easily analyzed pesticides,
higher precision and accuracy of results will be expected.
19
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A sampling efficiency of 75% should, in general, be
considered satisfactory for a collection medium. For the
more easily trapped pesticides such as DDT and mirex,
sampling efficiencies should be essentially quantitative.
Reuseability of sorbents is considered important; as a
guideline, at least six months of repeated use should be
expected before loss in sampling efficiency is noted.
The sorbents selected are also expected to vary little in
trapping and retaining test compounds with changes in
temperature and humidity.
7. Collection of Air Samples
A EPA/SURC air sampler may be operated at ground level or on
roof tops. In urban or congested areas, it is recommended
that the sampler be placed on the roof of a single-story
building. The sampler should be located in an unobstructed
area, at least two meters from an obstacle to air flow. The
exhaust hose should be stretched out in the downwind direction,
if possible. The sampler should be operated for 24 hours in
order to obtain average daily levels of airborne pesticides.
(Air concentration may fluctuate with time of day, temperature,
humidity, wind direction and velocity, and other climatological
conditions.) On and off times and weather conditions during
the sampling period should be recorded. Air flow readings
20
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should be taken (from the Magnehelic gauge) at the beginning
and end of each sampling period. The chart from the Dickson
recorder should be examined to note the occurrence and duration
of any power failure and any change in sampling rate during
the period. Blower motor brushes should be inspected frequently
and replaced, as necessary. An electrical power source of 110
VAC, 15A is required.
The glass sampling cartridge and glass fiber filter (on the
EPA/SWRI) should be removed from the sampler with forceps and
clean, gloved hands and immediately placed in a sealed container(s)
for transport to the laboratory. Similar care should be taken
to prevent contamination of the filter and vapor trap when
loading the sampler.
8. Results and Discussion
The greatest value of the high volume collection system is
2
that is provides a large sampling of air (at least 300 m /24
hours). Thus, even with poorly trapped compounds, sufficient
quantities can be collected to detect very low air concentra-
tion. For efficiently collected compounds, detection limits
can be extended to the subpicogram-per-cubic-meter range, and
sufficient quantities can often be trapped in 24 hours to
provide for mass spectrometric confirmation.
21
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III. SOURCE SAMPLING:
Contaminated, or source-related, atmospheres generally present less
problems with respect to either the sampling process or analytical
measurement because of the higher levels of pesticide present.
However, source sampling often requires special sampling equipment
that is portable, battery-powered, or is otherwise commensurate
with specific sampling needs. Often it is also not practical (or
desirable) to collect 24-hour samples. Thus a relatively high-flow
device, which may also need to be portable and/or battery operated,
may be required.
Monitoring atmospheres inside domiciles or workplaces requires a
sampler that is unobtrusive and operates quietly, does not get in
residents' or workers' way, and places little or no time or financial
7 8
demands on the site owner to maintain. ' Similar requirements are
made on devices used to monitor inspired air. They need to be worn
on the person; hence, must be battery-operated, light weight,
comfortable and quiet. Ideally, they should sample air at flow
rates similar to normal human respiration. Since indoor levels are
generally much higher than outdoor levels, due mainly to pest
control measures exercised inside domiciles and places of employment,
small, low volume air samplers may be used. Sampling rates in the
1 to 10 liters/minute range are adequate and can be provided with
any of several personal air sampling pumps on the market. These
pumps can be operated on batteries for up to 8 hours or for longer
periods if attached via a charging unit to 110 VAC house current.
22
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1. High Volume Source Sampler
A high volume sampler developed for the U.S. Army and manufac-
g
tured by Environmental Research Corporation (ERCO), a subsidiary
of Dart Industries, St. Paul, MN, is shown in Figure 7. Air
is drawn at flow rates up to 185 liters/minute through either
or both of two parallel 15 cm composite filter pads comprised
®
of Porapak sandwiched between two layers of glass fiber mat.
The major advantage of the ERCO sampler for source air monitoring
is that it provides a relatively large sample size with short
sampling times. It is compact and light weight, which makes
it highly portable. The model studied was equipped for either
AC or DC power and could be operated on a heavy duty automobile
battery at flow rates up to 160 liters/minute. The greatest
disadvantage of the system is the high cost of the composite
filter pads, which cannot be reused.
2. Low Volume Indoor Source Samplers
a. Pumps:
DuPont Constant Flow Sampling Pump, Model P4000A (includes
charger), Catalog No. 66-241 (Fig. 8). DuPont, Applied
Technology Division, Wilmington, DE 19898.
or
23
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Figure 7. A high-volume air sampler developed for the U.S. Army by
Environmental Research Corporation (ERCO). Shown to the right are the
composite filter pads used to trap airborne pesticides.
24
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TM
MSA Monitaire Sampler, Model S, Catalog No, 458475 and
charger No. 456059. Mine Safety Appliances Company, 600
Penn Center Boulevard, Pittsburgh, PA 15235.
Both of these small, battery operated pumps are capable
of pumping air through an 18 mm diameter x 50 mm cylindrical
PUF plug at 2.5 to 4 liters/minute for at least 8 hours
with a fully charged battery pack. The DuPont pump (Fig.
8) has the advantage that it will automatically adjust
its pumping rate to compensate for changes in flow resistance
(e.g., due to accumulation of particulate matter at the
intake of the collection module). It also operates more
quietly than the MSA and can be programmed to stop sampling
after a prescribed period.
b. Collection Devices:
Any glass, metal or Teflon cartridge capable of holding a
cylindrical plug of polyurethane foam (approximate volume
3 3
15 to 20 cm ) or 5 to 10 cm of granular sorbent can be
used. Several collection modules are shown in Figure 9,
along with a portable pump.
25
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Figure 8. The DuPont constant flow sampling pump (cover removed) and
battery charger.
26
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Ji.
a
Figure 9. Personal sampling pump and three collection modules, (a) Poly-
urethane foam with particulate filter in an all Teflon container (b) poly-
urethane foam in glass holder, and (c) polyurethane foam with particulate
filter in an all aluminium container.
27
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Module a is an all Teflon container containing a 4.5 cm
diameter x 3 cm foam plug preceded by a 5 cm diameter
glass fiber filter (Gelman Type A or MSA CT-75428) mounted
in the cap. This collection module should only be used
for stationary sampling since it is too heavy to be worn.
Module b is an open glass tube, 2 cm i.d. x 5 cm, con-
nected to a 7 mm o.d. open tip on one end for attachment
to the plastic tubing. The foam plug is cut slightly
oversized 2 cm x 4 cm for a compression fit. This module
has no provision for separate collection of particulate
matter.
Module c is an all aluminium container (a 35 mm film can)
containing a 3.2 cm diameter x 3.5 cm foam plug preceded
by a 3 cm glass fiber filter (Gelman Type A or MSA CT-75428)
(S\
mounted in the cap. A Swageluk hose nipple is sealed in
the bottom of the can.
Modules b and c are most suitable for use with granular
sorbents. It is suggested that small cylinders of poly-
urethane foam be inserted before and after the granular
sorbent to retain the latter in place.
28
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c. Preparation and Analysis of Sorbents and Glass Fiber
Filters
Follow the same basic procedures described in section
11,5. Scale down volumes for the smaller plugs or quantities
of granular sorbents used. Smaller Soxhlet extractors
will cycle more frequently (e.g., 8 cycles/hour). Because
efficient extraction of pesticide from glass module b
(Fig. 9) will probably not be achieved with the sorbent
in place, extract the foam and sorbent separately. Cut
glass fiber filters to size, wrap loosely in aluminum
foil, heat to 315°C in a muffle furnace overnight to
remove any organic material, and place in a desiccator
until use.
d. Calibration of Air Sampler
For low volume samplers, a simple soap bubble meter is
adequate for calibration. MSA pumps may also be cali-
brated by displacing water from an inverted graduated
cylinder (1 or 2 L size) during a measured length of
time.
29
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Commercial calibration units are also available from Mine
Safety Appliances (Catalog No. 457629), shown in Figure
10 and from DuPont (Catalog No. 66-242-f-l) as seen in
Figure 11.
When polyurethane foam alone is used, as in module b
(Fig. 9), the sampling pump may be calibrated without the
module attached. However, the additional use of a prefilter
or granular sorbents causes sufficient pressure drops
across the sampling module to require calibration with
the loaded module in place. In all cases, it is suggested
that the loaded sampling module be installed during
calibration, or there may be very large differences
between the pump flow meter reading and actual flow
through the module.
For calibration, some means of adapting the intake face
of the module into the calibration system must be devised.
For module b, laboratory "bubble" tubing (3/4 to 3/8
inch) may be used. (A suggested source of the latter is
Sherwood Medical Industries, Argyle, NY). When a commerical
calibration system is used, the manufacturer's instructions
should be followed.
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Figure 10. Calibration unit for the MSA personal sampling pumps.
(a) Manometer, (b) soap bubble meter, one liter, (c) rubber bulb, (d) stop
watch, (e) needle valve, (f) pump being calibrated, (g) voltmeter, 0-10
V, and (h) soap solution reservoir.
31
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pressure drop meter; (e) pump being calibrated
32
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e. Determination of Sampling Efficiencies for Specific
Pesticides
Measured quantities of pesticides in a volatile solvent
such as n-hexane are placed in a suitable container, such
as a U-tube or a midget impinger, which is attached to
the sampling module. The container should be temperature
controlled with a heated water bath or heating block to
slowly volatilize the pesticide. After the sampling
period (which should be as long as that anticipated in
actual monitoring studies), the amount of pesticide
remaining in the container and that collected by the
sorbent is determined to establish collection efficiency.
Sampling periods should be 4 to 8 hours.
A unit can be constructed to facilitate the measurement
of collection efficiencies. A midget impinger (Ace
Glass Cat. No. 7531-10) with the nozzle cut off at the
base of the joint and modified with an o-ring seal joint
(Ace Glass Cat. No. 7664-110) at the side arm can be used
to hold the pesticide solution. Two glass modules of the
same type as sampling module b (2,b.) are constructed
with O-ring seal joints (Ace Cat. No. 7664-116) on their
large end. One of the modules also has an o-ring seal
joint (Ace Glass Cat. No. 7664-110) on its small end.
33
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With this system set up as shown in Figure 12, there are
only glass connections between the pesticide solution and
the sorbent. This avoids the use of plastics which
results in a loss of efficiency.
f. Collection of Air Samples
For determination of pesticide residues indoors, air
samples should be taken in as many locations as necessary
to achieve a profile of the distribution throughout the
building. In houses with forced-air heating and/or air
conditioning, air concentrations will tend to be equili-
brated, although there will probably be areas in rooms
where circulation is impaired. Unlike the situation in
outdoor air, there should be little diurnal variation in
pesticide levels. Concentrations may vary more widely in
houses without air circulating devices, and may also be
weather dependent (i.e., depend on whether windows and
doors to the outside are open or closed).
Nearly all domiciles and many other buildings are given
preconstruction termite treatment. This results in a
slow release of the insecticide over very long periods of
time (at least up to 25 years). In buildings where
circulation is poor, airborne termitacide levels may be
34
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AIR INLET
AIR TO PUMPING
SYSTEM
Figure 12. Midget impinger used for collection efficiency studies.
35
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higher in basements or ground floors than on other floors.
In plenum houses, the crawl space under the house
serves as the plenum in the air distribution system,
which contributes substantially to the transport of
termitacide to other portions of the dwelling.
Kitchens and bathrooms are favorite areas for insects
such as roaches, ants, and silverfish; consequently, the
application of insecticides in these areas is common
practice. The chemicals are usually applied in baits or
in slow-release formulations, so that pesticides may be
emitted into the air for many months after treatment.
Similarly, crack and crevice treatment for pest control
is popular in commercial buildings.
The design of the structure and history of its past
control treatment should be taken into account when
planning an air monitoring project. Several samplers
should be used at once to obtain a distribution profile
of pesticide levels in the building. Normally, an 8 hour
sampling period at about 2 liters/minute is sufficient to
obtain an adequate sample for analysis. In this period,
3
about one m of air is sampled, which should provide a
3
detection limit of 0.1 ug/m or lower for most pesticides.
This level is one-tenth that of the National Institute of
36
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Occupational Safety and Health proposed standard of 1
3
ug/m for a 10 hour work day, 40 hour work week exposure
to carcinogenic compounds. Although the portable pumps
described earlier in this section are designed to operate
for 8 hours on fully charged battery packs, house current
(through the battery charger) should be used when available
to assure more uniform pumping rates during the sampling
period.
The air intakes of the sampling modules should be placed
one or two meters above floor level and oriented downward
or horizontally. If oriented upward, non-respirable
pesticide loaded dust may be collected. If pesticide
residues on household dust particles appear to be very
significant, a prefilter should always be used.
IV. WORKPLACE AIR - PERSONNEL MONITORING:
Inhalation of airborne dust and vapors containing high concen-
trations of pesticides constitutes a serious hazard to pest control
operators, pesticide formulators, and other persons occupationally
involved in agricultural industry. Respiratory exposure can be
best assessed through the use of a personal monitor worn on the
body while working in areas of high pesticidal contamination.
37
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Air Sampling Devices
The small sampling units described in the previous section are
designed for personal monitoring. They are battery operated
and can be worn on the body.
The MSA pump weighs 870 grams and may be worn comfortably on
the waist belt. The DuPont pump is also designed to be attached
to a waist belt, but is somewhat heavier (1.2 kg with battery
packs that are required for 8 hours of operation). The ability
of the DuPont pump to compensate for changes in flow resistance
and to be programmed to stop sampling after a prescribed
period more than make up for the slight inconvenience of its
added weight. DuPont markets a smaller constant flow unit
that weighs only 400 grams, but it draws only 200 ml/minute at
full flow (no resistance). In order to achieve the sensitivity
3
in the 0.1 to 1 ug/m range for many pesticides, flow rates of
1 to 3 liters/minute are needed, particularly for sampling
periods that are necessarily shorter than 8 hours. The sam-
pling modules are attached to the shirt collar or lapel to
monitor air in the breathing zone. The intake should be
oriented downward to exclude large dust particles, which may
not enter the nostrils.
It has been pointed out that estimation of respiratory exposure
in areas of high pesticide concentration is accurate only for
38
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true gases, due to the probable lack of uniform dispersion of
particulate matter in the breathing zone. The aerodynamics of
respiration through the nostrils is difficult to duplicate
with an air sampler. Most sampling devices also will not
differentiate between particles that would be trapped in the
nasopharynx and the smaller respirable particles that reach
the lungs. However, a small cyclone sampler that separates
and discards nonrespirable particulates (above 10 urn in diam-
eter) is marketed by Mine Safety Appliances. The unit, called
the Gravimetric Dust Sampling Kit (MSA 456241), can be attached
to the collar or lapel and is designed to sample at three
calibrated flow rates (2.0, 1.8, and 1.6 liters/minute).
Respirable particulate matter collected in a filter cassette
may be analyzed for pesticide content. A separate vapor trap
(and pump) could be worn for comparative data.
2. Preparation and Handling of Samples
Pre- and post-treatment of sampling devices and analytical
procedures should be identical to those described in the
preceding sections. Special care should be exercised to avoid
contamination of samples in the field. Improper handling of
the collection module before or after the sampling period
could easily deposit a microgram of the material being monitored
(or interfering substance) on the sampling medium, which would
3
result in a false positive analysis of 1 ug/m . Therefore,
39
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the collection modules should be loaded in the laboratory and
sealed in hexane-rinsed aluminum foil or a clean, sealed glass
jar before transport to the field. An analyst should carefully
install the sampling device and instruct the wearer not to
touch or disturb it. The analyst should be present at the end
of the sampling period to remove the module, place it in a
sealed container, and transport it back to the laboratory.
3. Sampling Duration
Sampling times should be commensurate with known or antici-
pated exposure times. If potential exposure to airborne
pesticides is intermittent or brief, sampling should be per-
formed only during those periods. If exposure is continuously
uniform throughout the work day, sampling may be conducted for
only a portion of the day and the result extrapolated to
estimate the total exposure for the entire work period. If
exposure is not uniform but occurs for regular periodic cycles
during the work day, sampling should be conducted over the
entire work day to obtain an accumulated total exposure assessment.
The monitoring program selected should, of course, be the
result of careful planning in order to provide a realistic
assessment of worker exposure.
40
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4. Estimation of Inspired Quantities
Since the sampling rates achievable with small, battery oper-
ated pumps are substantially lower than the respiratory rates
of most workers, monitoring data must be extrapolated on the
basis of estimated lung ventilation values to obtain an assessment
of total exposure. Table 1 gives the average respiratory
rates and their normal ranges for men and women at rest and at
work. Values would be lower for children and elderly people.
Ideally, pulmonary function test (PFT) measurements should be
made on the worker while performing the job in order to deter-
mine the exact respiratory rate. Since PFT equipment and
personnel trained in its operation are not likely to be avail-
able, a subjective estimation must be made of the breathing
rate if an approximation of the total quantity of pesticide
inspired is desired. To the untrained eye, it may sometimes
be difficult to differentiate between light and heavy work.
Estimates of average respiration rates likely to be encountered
among persons occupationally exposed to pesticides have been
made by H. R. Wolfe based on many visual observations over
many years. These estimates, which are given in Table 2, are
subjective but may be better than inexperienced judgments.
They should not be used a priori unless the data are appro-
priately qualified. Also, unless the sampler used can differ-
entiate between respirable and nonrespirable particulate
41
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Table 1
Normal Respiratory Rates for Humans
Respiratory Rates in Liters per Minute
Level of
Activity
Rest
Light Work
Heavy Work
Adult
Avg.
7
29
60
Male
Range
6-10
27-31
50-90
Adult
Avg.
4
16
24
Female
Range
4-7
16-17
17-32
Data from reference 10.
42
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Table 2
Subjective Estimations of Respiratory
Rates for Pesticide Workers
Work Situation
Estimated
Respiratory Rate
(L/Min)
Agricultural Workers:
Sprayer Using Hand Gun and Dragging Hose
Driver of Tractor Pulling Spray Equipment
Fruit Thinner or Picker
Fl agger for Aircraft Spray Application
Pesticide Formulation Plant Workers:
Bagger (Filling small bags - 2 to 5 Ib.)
Bagger (Filling large bags - 50 Ib.)
Stacker (Stacks 50 Ib. bags or pallets)
Bagger and Stacker (Filling and stacking 50 Ib.
bags or pallets)
Boxer (Packing small bags into shipping boxes) . .
Fork Lift Operator
Mixer (emptying bags of dry pesticide into hopper
for blending)
Worker cleaning inside of hoppers and bins ....
Adult Male*
50-67
18
29-30
18
29-30
32-33
33-42
33-42
30-32
20
33
33
Adult Female**
22-25
10
16
10
16
17
17-20
17-20
16-17
12
17
17
*Based on numerous visual observations by H. F. Wolfe and the respiratory rates given in
Table 1.
**Calculated as the percent of the male rate using data in Table 1.
43
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matter, it cannot be assumed that the quantity of pesticides
collected is proportional to the total inspired into the
1ungs.
44
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V. REFERENCES:
1. Lewis, R. G. Sampling and Analysis of Airborne Pesticides.
In Air Pollution from Pesticides and Agricultural Processes,
R. E. Lee, Jr. (Ed.), CRC Press, 1976, pp. 52-94.
2. Lewis, R. G. , A. R. Brown and M. D. Jackson. Evaluation of
Polyurethane Foam for Sampling of Pesticides, Polychlorinated
Biphenyls, and Polychlorinated Naphthalenes in Ambient Air.
Anal. Chem. 49, 1668-1672 (1972).
3. Lewis, R. G., K. E. MacLeod and M. D. Jackson. Sampling
Methodologies for Airborne Pesticides and Polychlorinated
Biphenyls. Paper No. 65, Chemical Congress, ACS-Chemical
Society of Japan, Honolulu, Hawaii, April 2-6, 1979.
4. Jackson, M. D. and R. G. Lewis. Polyurethane Foam and Selected
Sorbents as Collection Media for Airborne Pesticides. Conference
on Sampling and Analysis of Toxic Organics in the Atmosphere.
Am. Soc. Testing and Materials and EPA, Boulder, CO, August 6-9,
1979.
5. Bjorkland, J., B. Compton and G. Zweig. Development of Methods
for Collection and Analysis of Airborne Pesticides. Report
prepared for contract CPA 70-15, National Air Pollution Control
Administration, Durham, NC, 1970.
6. Rhodes, J. W. and D. E. Johnson. Evaluation of Collection
Media for Low Levels of Airborne Pesticides. U.S. EPA Research
Triangle Park, NC 27711, EPA-600/1-77-050, October 1977.
45
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7. MacLeod, K. E. Sources of Emissions of Polychlorinated Biphenyls
into the Ambient Atmosphere and Indoor Air. EPA-600/4-78-022,
March 1979. Analytical Chemistry Branch, ETD, HERL, Research
Triangle Park, NC 27711.
8. MacLeod, K. E. and R. G. Lewis. Monitoring Atmospheric Contami-
nation from PCB Sources. Presented at Conference on Sampling
and Analysis of Toxic Organics in the Atmosphere. Am. Soc.
Testing and Materials and EPA, Boulder, CO, August 6-9, 1979.
9. Lissick, M. 0. and W. A. Bosin. Development of an Efficient
High-volume Sampling System for Alkyl Phosphonate Vapors at
the PPB Concentration Level. Report Number 8-7613, Environmental
Research Corporation, St. Paul, 1975.
10. Spector, W. S. Handbook of Biological Data, W. B. Saunders
Co. , Philadelphia, 1956.
11. Wolfe, H. R. Private communication.
46
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
REPORT NO.
EPA-600/2-80-180
2.
3. RECIPIENT'S ACCESSI ON-NO.
TITLE AND SUBTITLE
PROTOCOL FOR ASSESSMENT OF HUMAN EXPOSURE TO
AIRBORNE PESTICIDES
5. REPORT DATE
August 1980
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Robert G. Lewis, Merrill D. Jackson and
Kathryn E. MacLeod
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Analytical Chemistry Branch
Environmental Toxicology Division
Health Effects Research Laboratory
Research Triangle Park, NC 27711
10. PROGRAM ELEMENT NO.
1EA615
11. CONTRACT/GRANT NO.
N/A
12. SPONSORING AGENCY NAME AND ADDRESS
Health Effects Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
RTP
NC
14. SPONSORING AGENCY CODE
EPA 600/11
15. SUPPLEMENTARY NOTES
16. ABSTRACT
The Environmental Protection Agency has been given the authority for
monitoring the air for pesticides. This protocol reports on methodology
that has been developed to assure that the air samples collected will give
adequate information on the exposure of the general population to
pesticidal air pollutants.
Descriptions are given of pumps, sorbents, calibration methods, and
preparations necessary for accurate data collections. The determination
of sampling efficiencies and respiratory exposure is also discussed.
17.
KEY WORDS AND DOCUMENT ANALYSSS
DESCRIPTORS
"b.lDENTlFiERS/OPEN ENDED TERMS
c. COSATI Field/Group
Pesticides
Exposure
Airborne
Protocol
06, T
18. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGES
55
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
47
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