United States
Environmental Protection
Agency
National Exposure Research
Laboratory
Research Triangle Park, NC 27711
Research and Development
EPA/600/SR-97/119 January 1998
Project Summary
Evaluation of Methods for
Collecting Dislodgeable Pesticide
Residues from Turf
Christopher R. Fortune
Three surface dislodgeable residue
collection methods were evaluated in
two tests performed on turf treated with
pesticide formulations. The test plots
used were typical of the turf found in
lawns of local residents. The polyure-
thane foam (PDF) roller and the Dow
sled methods were tested side-by-side
on turf treated with a mixture of
chlorpyrifos and chlorothalonil. The
PDF roller and California roller meth-
ods were tested side-by-side on turf
treated with a mixture of dicamba,
mecoprop, and 2,4-D. A pressurized
tank sprayer was used to apply the
pesticide formulations according to
manufacturer's label directions. Test
plots were mowed so that the mower
direction was kept the same over the
entire plot. Both tests were conducted
by performing replicate sampling in
separate areas of the plots so that the
sampler direction was with, against, or
across the cutting direction of the
mower.
All three test methods were evalu-
ated on the basis of their sampling
precision and transfer efficiency data.
Another important criterion considered
was the affinity of the sample media to
become contaminated with grass clip-
pings and debris during sample collec-
tion. Low recoveries of target analytes
from some spiked media samples were
an additional consideration. After con-
sidering all of these factors, we deter-
mined that the PDF roller method was
the least suitable for turf residue sam-
pling under our test conditions. The
Dow sled method was more suitable,
but the small sled proved unstable in
tests on deeper turf, so the test data
was limited. The California roller
method proved to be the most suitable
procedure.
This Project Summary was developed
by the National Exposure Research
Laboratory's Human Exposure and At-
mospheric Sciences Division, Research
Triangle Park, NC, to announce key
findings of the evaluation that is fully
documented in a separate report (see
ordering information at back.)
Introduction
The levels and distribution of pesticide
residues in residential environments is a
subject of concern because of the poten-
tial exposure risk such contaminants pose
for small children. The application of pes-
ticides to residential lawns for control of
insects, weeds, and turf diseases consti-
tutes the primary source of surface
dislodgeable residues. The U.S. Environ-
mental Protection Agency has been ac-
tive in conducting research efforts to de-
velop methodologies for monitoring sur-
face dislodgeable pesticide residues on
indoor surfaces and floors and on outdoor
surfaces and lawns. These efforts are in
response to the Office of Pollution Pre-
vention and Toxics, which is currently in-
volved in the development of testing guide-
lines for post-application exposure. The
guidelines are applicable to both occupa-
tional reentry and residential exposure and
are designed to cover data requirements
necessary to support the registration of
pesticide products under 40 CFR part 158.
A recent study designed to measure
the transport of lawn-applied acid herbi-
cides from turf into the home used human
subjects to simulate track-in transport of
dislodgeable residues from treated turf
plots to outside doormats and indoor car-
pet surfaces. The Southwest Research
Institute (SwRI) PUF roller method was
used to monitor dislodgeable residues on
both the indoor carpet surfaces and on
the treated turf plot. A round-robin test
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was just recently conducted to evaluate
the PUF roller and two other methods in
measuring dislodgeable pesticide residues
on indoor carpet. In this current study,
those same three methods, the SwRI PUF
roller, the California cloth roller, and the
Dow drag sled were evaluated in two tests
conducted on treated turf.
The turf test plots used in this study
were located on the grounds of a ManTech
Environmental facility in Research Triangle
Park, NC. While the grounds are main-
tained by a professional service, the test
plots used here were not of the high qual-
ity that would be found at a turf research
facility. Consequently, they were more typi-
cal of the "real world" residential lawn in
that they contained a substantial portion
of weeds and exhibited a more uneven
and generally lower turf density. After mow-
ing, two separate test plots were treated
with commonly used formulations: an in-
secticide and fungicide in the first test,
and an acid herbicide mixture in the sec-
ond test. Deposition coupons were placed
on the test surface prior to spraying the
formulations to determine the amount and
uniformity of the pesticide application. Field
blank samples and field spike samples
were collected for each method used in
each test. Written standard operating pro-
cedures (SOPs) for the test methods were
followed in performing replicate sampling
on each test plot.
The test results were used to calculate
the sampling precision for each target
analyte in terms of the percent relative
standard deviation of three replicate
samples for each method. The transfer
efficiency of each method was determined
by calculating the ratio of the average
transfer rate to the average deposition
rate for each target analyte as determined
by analysis of the deposition coupon
samples. The performance of each
dislodgeable residue sampling method was
evaluated based on these results and on
other key factors relating to the sample
media, sample handling, and the quality
control sample analysis results. All of the
analytical laboratory work performed in this
study was provided by Southwest Re-
search Institute, San Antonio, TX. In addi-
tion to performing all of the test sample
extraction and GC/MS analysis work, they
provided all of the pre-cleaned sample
media and the laboratory standard spike
solutions.
Study Design
Turf test plots were designed to contain
three separate 8- x 10-ft sections that
would permit the collection of three repli-
cate samples with each test method in
each section. The plots were mowed one
day prior to the test application and in a
manner such that the mower direction was
kept constant throughout the process.
Sampling was then performed so that the
sampler direction in each test section var-
ied relative to the cutting direction of the
mower, that is, the same direction, the
perpendicular direction, and the opposite
direction.
Combination Insecticide and
Fungicide Application Test
This test was designed to evaluate the
PUF roller method and the Dow drag sled
method in side-by-side sampling. The
sample traverse for both methods was a
single pass of 2.0 m in length. A commer-
cially available mixture of the insecticide
chlorpyrifos and the fungicide chlorothalonil
was prepared in water and applied ac-
cording to manufacturer's recommenda-
tions. The formulation (0.17% chlorpyrifos,
1.41% chlorothalonil) was applied at a rate
of 1 gal/500 ft2 using a compressed air
tank sprayer. Three a-cellulose deposition
coupons were evenly distributed over each
test section prior to spraying. This test
was conducted in hot and relatively dry
conditions during the month of July.
Acid Herbicide Application Test
This test was designed to evaluate all
three of the dislodgeable residue test meth-
ods, including the California roller method.
The procedures employed in the first test
were generally followed. Due to the addi-
tional sampling area required by the addi-
tion of the California roller method to the
test protocol, a fourth test section was
prepared for treatment. Two replicate
samples were collected with the California
roller method in each of the first three test
sections, and an additional three samples
were collected in the fourth section. A
commercial mixture of acid herbicides was
mixed in water according to manufacturer's
recommendations yielding a formulation
containing 0.007% dicamba, 0.03%
mecoprop, and 0.06% 2,4-D. The mixture
was applied to the test plot at a rate of 1
gal/250 ft2. In contrast to the conditions
that marked the first test in this study, this
second test was conducted during cool
and relatively wet conditions in the month
of October.
Test Methods
a-Cellulose Deposition Coupon
The deposition coupons used were 100-
mm squares of cellulose filter paper at-
tached to aluminum foil-covered backing
sheets of the same size. Each coupon
was marked by pencil line so that a 12.5-
mm (0.5-in.) border on all sides was avail-
able to allow handling. Prior to extraction,
the coupon border was trimmed away to
leave a 75-mm square (56.25 cm2) filter
sample for analysis in the laboratory. Esti-
mates of the deposition rate for a given
sample were determined from the ratio of
the mass of pesticide residue found on
the coupon to its area and were usually
reported in units of micrograms per square
centimeter.
PUF Roller
The PUF roller dislodgeable residue
sampling method uses a prototype me-
chanical apparatus having two rear wheels,
a cylindrical aluminum roller at the front,
and a handle for pushing or pulling at-
tached at the rear. Two stainless steel
blocks (total weight = 3.97 kg) are at-
tached to the center portion of the frame.
A PUF ring measuring 90-mm o.d.- x 30-
mm i.d.- x 76-mm in length was fitted onto
the aluminum cylinder, which was then
attached to the front of the sampler as-
sembly.
The location of the sample was marked
on the test plot by placing a metal guidebar
adjacent to the planned track of the de-
vice. The 200-cm sample traverse dis-
tance was marked off in 10-cm segments
on the bar. A solvent-washed thin alumi-
num sheet was placed at the starting po-
sition to serve as a platform to hold the
PUF roller before starting the test.
A sample traverse consisted of a single
pass over the 200-cm pathlength. At the
end of the traverse, the roller was imme-
diately lifted off of the turf. The aluminum
cylinder was then detached from the as-
sembly, and the PUF ring was recovered
and stored in its container. The marks at
10-cm intervals on the guidebar were used
to assist the operator in maintaining the
sampling rate at about 10 cm/s.
Dow Drag Sled
The Dow drag sled procedure uses a 3-
x 3-in. piece of 3/4-in.-thick plywood as
the base for a sled with a ridge con-
structed on the top to hold an 8-lb round
downrigger weight. A screw eye is placed
in the center of one edge of the block, to
which a 24-in long wire and pull handle
are attached. The base and sides of the
sled are covered with two layers of alumi-
num foil attached with staples.
The sampling media consists of
precleaned 4- x 4-in. undyed cotton denim
cloth squares. A thin aluminum sheet start-
ing platform and a metal guidebar were
used with the Dow sled procedure. A
sample traverse consisted of a single pass
with the sled over a distance of 200 cm
using guide marks at 10-cm intervals to
achieve an approximate sampling rate of
10 cm/s.
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The denim cloth sampling media is at-
tached to the base of the sled by using
plastic-headed pushpins positioned
through the overlapping edges of the cloth
and into the front and sides of the wooden
sled. With the denim cloth securely in
place, the sled was placed on the alumi-
num starting platform, and the 8-lb weight
was put into its position on top of the sled.
The drag line was then attached to the
screw eye on the front of the sled. Keep-
ing the drag line at a low angle relative to
the ground, the operator pulled the sled
forward at a steady rate until the front of
the sled reached the 200-cm mark on the
guidebar. The sled was then quickly lifted
from the turf, and the denim cloth was
removed from the sled, then folded and
stored in its container.
California Roller
The California roller method uses a de-
vice resembling a large rolling pin to col-
lect surface dislodgeable residues on a
percale sheet cloth matrix. The roller con-
sists of a 63-cm-long PVC pipe, 13 cm in
diameter, that is fitted with PVC endcaps
having roller handles. The roller is cov-
ered with a 1-cm-thick foam cover, 51 cm
in length, and is filled with a quantity of
small to medium-size steel ball bearings
sufficient to bring the total weight of the
roller to 11.3 kg.
The sampling medium, consisting of a
precleaned 17- x 17-in. cloth cut from
percale bedsheet material (50% combed
cotton, 50% FortrelŪ polyester, 180 thread
count), is placed flat on the turf and cov-
ered with a plastic sheet (e.g. medium-
size plastic trash bag, 20- x 24-in.). The
plastic sheet is held in place by driving 6-
in.-long metal spikes through the corners
of the sheet and into the ground. Sam-
pling is performed by moving the roller
back and forth ten times at a steady rate
over the sample medium (20 total passes).
A special metal handle assembly was fab-
ricated for use in these tests to permit the
operator to more comfortably move the
roller without exerting any downward pres-
sure on the handles. After the final sample
pass, the roller and handle assembly are
removed from the test area, the metal
spikes are removed, and the plastic sheet
is discarded. Forceps are then used to
collect and fold the percale cloth for inser-
tion into its sample container.
Sample Analysis
A wide variety of samples were handled
and analyzed in this study. In addition to
the three types of dislodgeable residue
samples collected from the two differently
treated test plots, quality control samples
were collected that included field blanks,
field spikes, raw formula samples, and
grass clippings and debris removed from
test sample media. The analytical labora-
tory, SwRI, followed specific SOPs for ex-
traction and analysis of each sample type
and group of target analytes to be deter-
mined. The laboratory also performed its
own internal quality control procedures that
included analysis of media and solvent
blanks, spiked samples, and addition of
surrogate compounds before extraction to
test sample recovery levels. Sample ex-
traction procedures for the chlorpyrifos/
chlorothalonil samples involved a cold-
shake extraction in solvent, concentration
by evaporation, and Florisil cleanup.
Sample extracts were then analyzed by
GC/MS using the selected ion monitoring
mode. Acid herbicide samples were ex-
tracted in an acidified water/ethanol solu-
tion followed by liquid-liquid extraction with
chloroform, solvent exchange, and then
derivatization to the methyl ester form of
the compounds. Analysis was by GC/MS
using a Fisons VG-MD800 instrument.
Results and Discussion
Analytical results for field and labora-
tory blanks and GC/MS calibrations were
acceptable in all cases. Surrogate com-
pound recoveries were acceptable for all
samples with two exceptions that were so
noted. Analysis of field and laboratory
spiked samples for chlorpyrifos and
chlorothalonil were acceptable for all me-
dia except for low recoveries (68%) of
chlorothalonil on the PUF media. Analysis
of field and laboratory spiked samples for
dicamba, mecoprop, and 2,4-D yielded
generally poor results. Only the percale
sheet (California roller method) media
yielded acceptable recoveries of all three
target analytes averaging 84% recovery,
with a minimum of 76%. The results indi-
cate inefficient extraction of the target
analytes from the PUF media and the
denim cloth media. Recoveries ranged
from a high of 69% for dicamba to a low
of 34% for 2,4-D, both from the PUF me-
dia.
Combination Insecticide and
Fungicide Application Test
The turf plot used in this test was mowed
to a height of two inches, and a four hour
drying period was allowed following appli-
cation of the pesticide formulation. The
deposition rate and uniformity of the appli-
cation were determined by placing three
deposition coupons in each of the three
test plot sections before spraying the turf
plot. The centrally located coupon in each
section was recovered immediately after
the spraying was completed. The remain-
ing coupons were recovered at intervals
concurrent with the individual sampling op-
erations. In each test section the two re-
maining coupons were combined for analy-
sis as a single sample. A uniform applica-
tion was indicated based on the results
for both sets of deposition coupons. The
calculated average deposition rate and the
corresponding percent relative standard
deviation for chlorpyrifos for coupons col-
lected immediately were 14.7 |j,g/cm2 +
10.9%, and for those collected later in the
day the results were 2.64 |ag/cm2 + 9.4%.
The corresponding data for chlorothalonil
was 180.6 lag/cm2 + 11.2% and 139.2 \igl
cm2 + 3.7%. The large decrease in the
levels of chlorpyrifos during the drying pe-
riod attests to the high volatility of this
compound.
The overall results for this test are pre-
sented in Table 1 for both the PUF roller
and the Dow drag sled methods. The
method transfer rate is the ratio of the
total pesticide collected to the total area
covered during the sample traverse. The
sampling precision is the calculated per-
cent relative standard deviation for repli-
cate sample results. The method transfer
efficiency is the ratio of the method trans-
fer rate to the pesticide deposition rate as
determined by the combined analysis of
the two depositions collected from each
test plot section at the time of sampling.
The sampling precision results were
mixed and not particularly good for either
of the two methods evaluated in this test.
The average transfer rate and the corre-
sponding transfer efficiency of the PUF
roller method were approximately twice
that of the Dow drag sled method for both
target compounds used.
Acid Herbicide Application Test
The turf plot used for this test was
mowed to a height of three inches, and a
three hour drying period was allowed fol-
lowing application of the acid herbicide
formulation. The deposition rate and uni-
formity of the pesticide application were
determined for this test by using deposi-
tion coupons in the same way as in the
earlier test. The calculated average depo-
sition rate and the corresponding percent
relative standard deviation for dicamba for
coupons collected immediately were 0.36
|ig/cm2 + 4.7%, and for those collected
later in the day the results were 0.36 |ig/
cm2 + 10.0%. The corresponding data for
mecoprop was 1.12 |ig/cm2 + 5.6% and
0.96 jag/cm2 + 17.2%. And for 2,4-D the
results were 2.64 |ig/cm2 + 14.0% and
2.82 jag/cm2 + 12.9%. These results show
that the application was uniform, and that
the levels of all three target compounds
remained stable throughout the drying pe-
riod.
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Table 1. Combination Insecticide and Fungicide Test Results
Method &
Target
Compounds
Transfer Rate
(mg/cm2)
Sampling
Precision
Transfer
Efficiency
PUF Roller
Chlorpyrifos 2.37
Chlorothalonil 401
Dow Drag Sled
Chlorpyrifos 1.05
Chlorothalonil 240
30.8%
62.0%
50.3%
19.3%
0.087%
0.293%
0.0390%
0.173%
At the onset of the sampling activities
for this test a problem was encountered
with the Dow drag sled procedure. The
weighted sled could not be dragged over
the turf surface without it falling over nu-
merous times during a 200-cm traverse. It
appears that the small sled, while func-
tioning normally in tests on shorter turf
(two inches high) earlier, could not remain
stable in the longer turf used for this test.
Consequently, the Dow drag sled was not
included in the sampling schedule con-
ducted on this test plot. Other studies
have been conducted using larger drag
sleds that have been found to be stable
for turf applications, but such a sled was
not available for use in this test. The over-
all results are presented in Table 2 for
both the PUF roller and California roller
methods. The method parameters shown
are the same as reported for the combi-
nation insecticide and fungicide earlier.
The results of the acid herbicide appli-
cation test are definitive. The sampling
precision and transfer efficiency of the PUF
roller method were similar to those same
results from the first test performed. In
both cases the method exhibited relatively
low precision and variable transfer effi-
ciency results. In contrast, the California
Table 2. Acid Herbicide Test Results
roller method exhibited relatively high pre-
cision and consistent transfer efficiency
results for this one test in which it was
evaluated.
Analysis of Grass Clippings
and Debris Removed from
Sample Media
A problem developed early on in this
study involving the grass clippings and
other debris that adhered to the sample
media following the performance of the
dislodgeable residue test runs. The prob-
lem was particularly serious for the PUF
roller sample media. Both the drag sled
denim cloth media and the California roller
percale sheet media were found to collect
small amounts of clippings and debris, but
these could be easily removed by the
laboratory analyst. The PUF roller media,
on the other hand, collected much larger
quantities of the debris, and it adhered
more strongly making removal tediously
difficult. Prior to extraction and analysis of
every sample collected during this study,
the sample media were meticulously
cleaned of debris and the removed mate-
rial was saved for later gravimetric and
Method & Target
Compounds
Transfer Rate
(mg/cm2)
Sampling
Precision
Transfer
Efficiency
PUF Roller
Dicamba
Mecoprop
2,4-D
0.66
2.48
4.89
43.7%
46.2%
47.7%
0.184%
0.257%
0.171%
California Roller
Dicamba
Mecoprop
2,4-D
1.78
5.19
15.63
12.2%
13.1%
10.1%
0.504%
0.548%
0.560%
chemical analysis. Analysis of debris ma-
terial removed from two each of the PUF
roller and Dow sled samples from the first
test revealed that the impact of the grass
and debris adhering to the media follow-
ing sampling was significant in the case of
the PUF roller for Chlorpyrifos. Because of
the relatively low Chlorpyrifos concentra-
tions and the greater bulk of grass and
debris collected on the PUF media versus
the Dow denim cloth, more than 25% of
the total Chlorpyrifos collected by the PUF
roller was due to grass and debris, while
less than 10% of the Dow sled Chlorpyrifos
was due to extraneous material. The much
higher sample concentrations of
Chlorothalonil significantly reduced the im-
pact of grass and debris contributions to
the sample totals for both methods, al-
though the PUF roller samples averaged
about 5% of the total collected, while the
Dow sled samples were below analytical
detection limits. Three samples each of
the debris removed from the PUF roller
media and the California roller media used
in sampling for the acid herbicide test
were similarly analyzed. The calculations
showing the percentage contribution of the
media sample and the debris sample to
the total sample results revealed the sig-
nificance of the problem posed by extra-
neous material picked up by sample me-
dia during tests on turf. For the PUF roller
test runs, more than 97% of the total
analyte concentration for all three acid
herbicide constituents was in the grass
clippings and debris sample fraction. And
even though the amount of grass and
debris removed from the percale sheet
media was much less than that from the
PUF sleeve, the grass clipping and debris
sample fraction accounted for about 70%
of the total analyte concentration for all
three acid herbicide constituents in those
samples. Gravimetric analysis of the ex-
traneous material removed from all three
types of sample media used in these tests
showed that the PUF roller media col-
lected an average of 17.4 mg of debris.
The average amount removed from Cali-
fornia roller percale sheet media was 6.4%
of that amount, and debris removed from
the Dow sled denim cloth media was only
1.5% of the PUF roller amount. These
results should serve to emphasize the
need to ensure that sampling media used
in turf measurements for pesticide resi-
dues be scrupulously cleaned of any and
all extraneous material prior to extraction
and analysis.
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Conclusions and
Recommendations
1. A pressurized tank sprayer was
used successfully in pesticide ap-
plications on two turf test plots.
Analysis of nine deposition coupons
from each test yielded average de-
viations in deposition rate of 8.8%
relative standard deviation (RSD)
for a pesticide/fungicide application
and 10.7% RSD for an acid herbi-
cide application.
2. The turf plots used in this study
were typical of local area lawns as
opposed to professionally main-
tained test plots such as have been
used in other studies of this type.
As such, the turf density of these
"real world" test plots was lower,
and they contained a substantial
proportion of weeds.
3. Laboratory and field quality control
sample results showed no target
analytes detected in sample media
or in field blanks collected on un-
treated test plots. Field and labora-
tory spiked sample results indicated
a problem with inefficient extraction
of chlorothalonil, dicamba,
mecoprop, and 2,4-D from PUF
sleeves. Spike recoveries of the
acid herbicides were also low for
the denim cloth samples.
4. For all three dislodgeable residue
collection methods, sample handling
for turf samples was complicated
by the adherence of grass clippings
and debris to the sample media
following sample runs. This prob-
lem was most severe for the PUF
roller, which collected about 20
times more material, by weight, than
either the California roller or the
Dow sled.
5. Analysis of grass clipping and de-
bris samples removed from PUF
roller and California roller samples
collected from the acid herbicide
test plot revealed that target analyte
levels in the grass clippings and
debris samples were 50 times
higher than levels in the PUF
sleeves and 2-6 times higher than
levels in the California roller cloths.
6. In the comparison of the PUF roller
and Dow sled methods on turf
treated with chlorpyrifos and
chlorothalonil, neither method ex-
hibited good sampling precision,
with results ranging from 20 to 50%
RSD. The Dow sled yielded better
consistency in the transfer efficiency
data, and neither method exhibited
a clear trend as to the effect of
sampling direction relative to the
mower direction used.
7. In the comparison of the PUF roller
and the California roller methods
on turf treated with the acid herbi-
cides, dicamba, mecoprop, and 2,4-
D, the PUF roller sampling preci-
sion averaged near 45% RSD, while
the California roller precision was a
surprisingly good 12% RSD on av-
erage. Transfer efficiency was vari-
able for the PUF roller averaging
about 0.2%, while the California
roller exhibited consistent transfer
efficiency at about 0.5%. For the
three sampling directions tested,
sampling precision was lower for
the PUF roller for sampling in the
same direction as the mower and,
for the California roller, precision
was higher for sampling in the op-
posite direction.
8. The evaluation of the PUF roller
method on treated turf revealed sev-
eral inherent problems with the tech-
nique in this real-world application.
Sampling precision was generally
poor, pesticides were not efficiently
extracted from the sample media,
and the PUF media was inordinately
prone to collecting grass clippings
and debris during sample runs. For
these reasons we do not recom-
mend that the PUF roller method
be used for dislodgeable residue
sampling on turf.
9. The evaluation of the Dow sled
method on treated turf was limited
because of the instability of the 3-
x 3-in. sled used. The available data
show that sampling precision was
low, but transfer efficiency was con-
sistent. The denim cloth media does
not tend to collect grass clippings
and debris, but the low extraction
efficiency for acid herbicides is a
source of concern. Further evalua-
tion of the Dow sled method on turf
is recommended, but a larger sled
base will be required.
10. The evaluation of the California
roller method on treated turf yielded
results showing high sampling pre-
cision and consistent transfer effi-
ciency. The percale sheet sampling
media does not tend to collect grass
clippings and debris, and extrac-
tion efficiency of the acid herbicide
target analytes was good. These
results, along with the availability
of a handle assembly permitting
upright operation of the roller, form
the basis for our giving the Califor-
nia roller method the best rating of
the three methods evaluated in this
study.
11. The results of tests comparing the
levels of the target analytes found
in grass clippings and debris re-
moved from the sample media to
the levels found in the media itself
establish the extreme importance
of scrupulous cleaning of the
dislodgeable residue sampling me-
dia, either at the time of sampling,
or at least prior to extraction for
analysis.
This work was performed by ManTech
Environmental Technology, Inc., under
U.S. EPA Contract 68-D5-0049, and by
Southwest Research Institute under Sub-
contract 96-0049-01 to ManTech.
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ChristopherR. Fortune is with ManTech Environmental Technology, Inc., Research
Triangle Park, NC 27709.
Robert G. Lewis is the EPA Project Officer (see below).
The complete report, entitled "Evaluation of Methods for Collecting Dislodgeable
Pesticide Residues from Turf," (Order No. PB98-114390; Cost: $21.50, subject to
change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
National Exposure Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
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Penalty for Private Use $300
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT NO. G-35
EPA/600/SR-97/119
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