EPA/600/A-97/075
Comparison of Commercial vs Homeowner Application for Transport of
Lawn-Applied Herbicide 2,4-D into Homes
Marcia Nishioka, Charles Hines, Marielle Brinkman, Hazel Burkholder
Battelle Memorial Institute
505 King Avenue; Columbus, OH, USA 43201
Robert G. Lewis
National Exposure Research Laboratory MD-77
U.S. EPA; Research Triangle Park, NC, USA 27711
ABSTRACT
Homeowners are participating in a three year study to measure the migration and
transport of lawn-applied herbicide acids 2,4-D (2,4-dichlorophenoxyacetic acid) and dicamba
into the home, the spatial distribution of these residues in the home, and the temporal profile
of exposures of residents to these residues. Associated activity patterns that are being
considered in the study design as contributing factors for transport and exposure include
homeowner vs commercial application, activity levels of children and pets, and wearing vs
removal of outdoor shoes indoors. Sample types being collected include air, surface wipes,
floor dust, dislodgeable carpet surface residues, handwipes and urine. All sample types are
collected pre- and post-application, over two one-week periods at each home. Studies have
included eight occupied and two unoccupied homes.
With both homeowner and commercial application, track-in is the most significant
transport factor contributing residues to the inside of the home. Reductions of 2-10 fold in
surface concentrations (jtg/nr) of 2,4-D and dicamba on floors, sills, and tables in main
living areas of the home were found with commercial application, relative to homeowner
application. This reduction is most likely due to the fact that the commercial applicator,
unlike the homeowner, does not enter the home with contaminated clothing and shoes after
application. Levels of 2,4-D in the child's bedroom were very similar, irrespective of
application, indicating the significance of their activity patterns for track-in. The changes in
floor dust levels were proportional to changes hi the PM10 air levels of 2,4-D, suggesting
dust resuspension in the home as a contributing factor for air levels and inhalation exposures.
INTRODUCTION
Agricultural pesticide studies have documented pesticide transport and translocation
through plants, soil, water, and air (1,2). Although pesticide applications are designed to
deposit the formulation onto a target plant, soil or insect surface, inadvertent translocation
and deposition often occurs via spray drift, soil/foliar resuspension, and/or volatilization (3).
An additional transport mechanism that has been identified for the residential environment is
"track-in" or transport of residues into the home on shoes and feet after walking over treated
turf (4). Recent field simulation studies of track-in have demonstrated a correlation between
turf dislodgeable residues and carpet residue levels (5).
Measurements of pesticide levels in indoor air and house dust have led researchers to
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conclude that segments of the U.S. population may undergo chronic exposure due to
residential pesticide applications (6). In some cases, the presence of insecticides such as
chlorpyrifos can be ascribed to the indoor use of whole room foggers and sprays. The
presence of semivolatile organochlorine pesticides, such as chlordane and DDT, indoors
appears to be due to infiltration and/or volatilization into the home of pesticides originally
applied to foundations. However, the presence indoors, of non-volatile pesticides such as 2,4-
D and chlorothalonil that are used exclusively outdoors, and often at a distance from the
home, strongly suggests the role of mechanisms such as track-in that involve particle
transport.
Transport of pesticides into the home carries potential implications for chronic human
exposure. Carpets, house dust, and home furnishings become long-term sinks for the
pesticides. The common environmental weathering factors such as wind, rain, soil microbes,
and sunlight are not available for degradation. Residues on floors and surfaces can become a
source of exposure for young children through hand-to-mouth non-dietary ingestion or via
inhalation of resuspended dust.
This manuscript describes selected results from studies in which sampling regimens
have been developed to elucidate the relative importance of various residential transport
mechanisms. The analyses have provided important information regarding both the spatial
and temporal distributions inside the home of pesticide residues following lawn application.
SAMPLING AND ANALYSIS
Sampling has been carried out at 8 homes which routinely apply the post-emergent
herbicide Trimec, or equivalent, that contains dicamba, mecoprop, and 2,4-D. With the
exception of one split level home, all homes were single-story ranch design, had turf on at
least three sides of the home, and a lawn area of 0.125-1 acre. All homes had two or three
school-age children and one pet (one exception). Sampling was carried out at each home
throughout a one-week pre-application period for background measurements, during the
herbicide application for turf deposition and spray drift, and during a one-week post-
application period. Deposition coupons on the lawn were used to assess application rate. A
cascade impactor was run inside the home during the lawn herbicide application to collect the
indoor component of spray drift aerosol in the following particle size ranges: < 1 /mi, 1-2
/mi, 2-8 /mi, and > 8 /mi.
The one-week pre-application and post-application periods had the same collection
regimen, consisting of 24 hr air sampling, wipe sampling of sills and tables, and vacuum
sampling of floors. The air sampling was performed with four co-located 4 L/min samplers
consisting of a T60A20 Teflon-coated glass fiber filter and PUF (polyurethane foam) sorbent
(URG-2500) with an inlet for particle size discrimination of either < 1 /mi, <2.5 /mi, < 10
/mi or <20 (total) /mi. Ah" samples were acquired on the first day (day one; day of
application for post-application week) and on the second day after application (day three).
The wipe samples of four table and four window sill surfaces, and vacuum samples from five
separate floor areas were collected on day seven. The floor surfaces typically included an
entry area, the main living room, dining area, kitchen and a child's bedroom. The sill and
table surfaces, to the extent possible, included areas in the living room, dining area, kitchen
and child's bedroom. Each sill and table surface was wiped with a Johnson & Johnson SOF-
WICK gauze wipe that was moistened before use with a small amount of a "sweat simulant",
a 70:30 phosphate buffenacetonitrile solution. Each surface was wiped twice in opposite
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directions. The floor dust samples were collected from 2 nr areas using the HVS3 vacuum
sampler (Cascade Stack Sampling Systems, Inc.), which is designed for controlled collection
of floor dust particles >5/mi (7). In addition to these samples, an integrated seven day air
exchange rate measurement (Brookhaven Laboratory) was collected at each home during the
post-application week.
The extraction, cleanup and analysis methods were similar for all matrices and
differed mainly in volume needed for extraction of each sampling medium. The basic method
included sonication extraction in a 30:70 phosphate buffer: acetonitrile solution, hexane
partition at high pH, CIS SPE cleanup, methylation with diazomethane, and GC/ECD
analysis. The method has been reported in detail elsewhere (5). The surrogate recovery
standard (SRS) was 3,4-D, and the internal standard for quantification was 2,6-D (note both
are positional isomers of 2,4-D and expected to act similarly). Quantification was based on
linear regression from multi-point calibration solutions prepared for each matrix over the
expected analyte concentration range,
RESULTS AND DISCUSSION
The recoveries of analytes dicamba and 2,4-D, in both free acid and salt form, and
recovery of the SRS 3,4-D (free acid only) from the various sampling media are listed in
Table 1. As shown there, recoveries were essentially quantitative (>85%), with minor
exception, from all media, and slightly higher for the salt form relative to the free acid. In
addition, 3,4-D appears to function as an excellent SRS, in that its recovery very closely
mirrors the recoveries of analytes.
Measurement of spiked analytes on the filter/PUF sampling system following sampling
for 24 hrs at room temperature showed that analytes were fully retained in either free acid
form or salt form. Except at high relative humidity, analytes were retained on the filter.
The data presented here in Figures 1-3 show the comparisons between Year 1
(homeowner application) and Year 2 (commercial applicator) for two representative homes for
selected sample types. Home A was categorized as a home with high child activity and high
pet activity, and Home B had low levels of both child and pet activity. In addition, adults
and children in Home B routinely removed shoes at the door when entering from outside; this
practice was not observed in Home A.
In Figure 1 are shown the floor dust surface loading of 2,4-D in four areas of each
home on Day 7 post-application . Three distinct trends were noted for the study homes in
comparing homeowner vs commercial application, and these trends are shown with these two
homes. First, for homes such as A, where shoes are not removed at the door, the
commercial application resulted in substantially lower surface loadings of 2,4-D in floor dust,
by a factor of 3-4X, hi main living rooms of the house. Presumably, a significant proportion
of the track-in 2,4-D came in on the clothing and shoes of the homeowner/applicator.
Second, in all homes, represented here by Homes A and B, the floor dust surface loading of
2,4-D was nearly identical in the child's bedroom irrespective of the application method. We
assume that the activity patterns of the child are largely responsible for the track-in seen in
their room, and, that child track-in component is not altered substantially by the application
method. In those homes where shoes are removed routinely, the psycho-social aspects of
participation in a study may be somewhat in evidence. Homeowners report that it is difficult
to enforce consistently a "no shoes indoors" policy, and it is the lessening of reminders that
may be responsible for the 2-3X higher levels in the second year of the study. In Home B,
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the bedroom sampled belonged to the child who cut neighbors' grass, and this activity may
help to explain the higher levels there, relative to the rest of the house, in the first year study.
The levels of 2,4-D on table surfaces in Homes A and B are shown in Figure 2.
Comparing data in Figures 1 and 2 for Home A, we note that the difference between floor
and table loadings (/ig/nr) was roughly a factor of 10, In a manner analogous to the floor
dust 2,4-D surface loadings of Home A, there was also a 2-3X reduction hi table surface 2,4-
D levels between homeowner and commercial applications. The decline hi 2,4-D table levels
that mirrors the floor levels as a function of the traffic pattern through the house tends to
indicate that the majority of 2,4-D on tables here results from resuspended floor dust. In
contrast, the data for Home B are somewhat more difficult to rationalize with respect to the
floor dust levels, especially in light of the similarity hi floor and table loadings, the similarity
in table loadings throughout the house, and the lower overall activity level in the home.
These data suggest that a substantial portion of the table surface 2,4-D in Home B resulted
from airborne intrusion and settling. Note that hi Year 1, the preparation and mixing of 2,4-D
before application took place outside the kitchen window.
The levels of 2,4-D in the indoor air two days after application for Homes A and B
are shown in Figure 3. The levels of 2,4-D in the PM10 air particles are roughly
proportional to the levels in the floor dust. Thus, where floor dust levels were lower in Year
2 with respect to Year 1 for home A, the air levels in PM10 particles were also lower. The
same trend was observed for Home B. These data may tend to support the assumption that
resuspension of floor dust is responsible for the PM10 levels of 2,4-D in indoor air. The
analyses of the co-located samplers for PM2.5 and PM1 show that the PM2.5 levels of 2,4-D
are comprised almost exclusively composed of 2,4-D on particles < 1 fan. These fine
particles may be associated with long term resuspension of 2,4-D from foliar surfaces and
subsequent drift. Given the similarity in air infiltration rates for all homes, it is not
surprising to find similar 2,4-D PM2.5 levels in the homes.
CONCLUSIONS
The data collected and presented here suggest that in-home ingestion and inhalation of
dust residues may contribute to children's exposures to pesticides in general, and 2,4-D in
particular. Following application of 2,4-D to a lawn, we have measured 2,4-D in the air and
on floor, sill, and table surfaces throughout each home. There was a 3-4X reduction to floor
levels and a 2-3X reduction in table surface levels for professional application, relative to
homeowner application, and this is believed to be due primarily to the fact that the
applicator's contaminated clothing and shoes are not brought into the home after application.
The low levels of 2,4-D on sills and tables in low activity homes may indicate the role of
foliar resuspension and intrusion, as indicated also by the presence of 2,4-D on particles that
are < 1 /im, on the second day after application.
Acknowledgment
Battelle acknowledges support of this work under U.S. EPA Cooperative Agreement
CR-822082. It has been subjected to Agency review and approved for publication. Mention
of tradenames or commercial products does not constitute endorsement or recommendation
for use.
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REFERENCES
1) Glotfelty, D.E.; J Air Pollut Control Assoc 1978, 28, 917-921.
2) Stanley, C.W.; Barney, I.E.; Helton, M.R.; Yobs, A.R.; Environ Sci Tech 1971, 5,
430-435.
3) Glotfelty, D.E.; Sehomburg, C.J.; McChesney, M.M.; Sagebiel, J.C.; Seiber, J.N.;
Chemosphere 1990, 21, 1303-1314.
4) Lewis, R.G.; Fortmann, R.C.; Camann, D.E.; Arch Environ Contam Toxicol 1994, 26,
37-46.
5) Nishioka, M.G.; Burkholder, H.M.; Brinkman, M.C.; Gordon, S.M.; Lewis, R.G.;
Environ Sci Tech 1996, 30, 3313-3320.
6) Whitmore, R.W.; Immerman, F.W.; Camann, D.E.; Bond, A.E.; Lewis, R.G.; Schaum,
J.L.; Arch Environ Contam Toxicol 1994, 26, 47-59.
7) ASTM. Standard Practice for Collection of Dust from Carpeted Floors for Chemical
Analysis D5438-93. In Annual Book of ASTM Standards, Vol 11.03; Phil., 1994.
Table 1. Recovery of Analytes and Surrogate Recovery Standard from Sampling Media
Sampling Medium
T60A20 Filter-air
URG PUF Sorbent-air
Impactor Plate w/PEG 1000
J&J Gauze Wipe-surfaces
Vacuumed House Dust
PUF Roller Sleeve
n
3
3
2
2
3
2
Recovery
Dicamba
(0.5 Mg)
90
84
82
68
87
84
of Spiked Analyte,
Free Acid
2,4-D 3
dMg)
93
86
83
86
84
105
%
,4-D /SRS
dMg)
92
88
88
87
93
105
Amine Salt Formulation
Sampling Medium
T60A20 Filter
URG PUF Sorbent
Impactor Plate w/PEG 1000
PUF Roller Sleeve
n
3
3
2
2
Dicamba
(0.1 Mg)
86
93
92
NT
2,4-D 3,4-D /SRS
(1 Mg) (1 jig-free acid)
90
90
93
89
94
95
91
NT
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2,4-D in Carpet Dust,
Yearl
Year 2
Application; Homeowner
Commercial
250-
Home A
High child activity
High pet activity
Shoes indoors
HomeB
Low child activity
Low pet activity
No shoes indoors
228
188
250-
45
67
40 -,
rn s [4li
Entry Liv Kit Bed Entry Liv Kit Bed
0.2
2
2
4
2
5
4
Entry/ Din Liv Bed Entry/ Din Liv Bed
Kit -f Kit 4
Figure 1. 2,4-D in House Dust for Homeowner and Commercial Application
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2,4-D on Tables, |jg/m2
Yearl
Application: Homeowner
25
22
25-i
Home A
High child activity
High pet activity
Home B
Low child activity
Low pet activity
Lfv
1.7
Liv
Kit
Kit Bed
3.3
1.1
Bed
25-,
Year 2
Commercial
10
Liv
1.3
Liv
1.3
Kit
Kit Bed
0.9
Bed
CO6/Ni5hiDk a/35-3
Figure 2, 2,4-D on Table Surfaces for Homeowner and Commercial Application
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254-D in Indoor Air, ng/m3
Two Days Post-Application
Yearl
Application: Homeowner
10.75
Home A u
High child activity
High pet activity
Home B
Low child activity
Low pet activity
Year 2
Commercial
1 CR
PM
2.5
ND
PM
2.5
f
PM
10
0.69
PM
10
10-
10-n
2.47
PM
2.5
2,2
PM
2.5
6.81
PM
10
2.59
PM
10
CD/Nishioka/36-1
Figure 3, 2,4-D in Indoor Air, Two Days Post-Application to Lawn
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TECHNICAL REPORT DATA
1, REPORT NO.
EPA/600/A-97/075
2.
4. TITLE AND SUBTITLE
Comparison of Commercial vs Homeowner Application
for Transport of Lawn-Applied Herbicide 2,4-D into
Homes
5.REPORT DATE
6.PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
'Marcia Nishioka, Charles Mines, Marielle Brinkman, Hazel Burkholder,
and ^Robert G. Lewis
8,PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
'Battelle Memorial Institute
505 King Avenue, Columbus, OH 43201
2 U.S. Environmental Protection Agency
National Environmental Research Laboratory
Research Triangle Park, NC
10.PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
U. S. Environmental Protection Agency
National Environmental Research Laboratory
Research Triangle Park, NC
13.TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
Homeowners are participating in a three year study to measure the migration and transport of lawn-applied herbicide
acids 2,4-D (2,4-dichlorophenoxyacetic acid) and dicamba into the home, the spatial distribution of these residues in the
home, and the temporal profile of exposures of residents to these residues. Associated activity patterns that are being
considered in the study design as contributing factors for transport and exposure include homeowner vs commercial
application, activity levels of children and pets, and wearing vs removal of outdoor shoes indoors. Sample types being
collected include air, surface wipes, and urine. All sample types are collected pre- and post-application, over two one-
week periods at each home. Studies have included eight occupied and two unoccupied homes.
With both homeowner and commercial application, track-in is the most significant transport factor contributing residues
to the inside of the home. Reductions of 2-10 fold in surface concentrations (j*g/m2) of 2,4-D and dicamba on floors,
sills, and tables in main living areas of the home were found with commercial application, relative to homeowner
application. This reduction is most likely due to the fact that the commercial applicator, unlike the homeowner, does not
enter the home with contaminated clothing and shoes after application. Levels of 2,4-D in the child's bedroom were
very similar, irrespective of application, indicating the significance of their activity patterns for track-in. The changes in
floor dust levels were proportional to changes in the PM10 air levels of 2,4-D, suggesting dust resuspension in the home
as a contributing factor for air levels and inhalation exposures.
17.
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