United States
Environmental Protection
Agency
National Exposure Research
Laboratory
Research Triangle Park, NC 27711
Research and Development
EPA/600/SR-97/110 January 1998
Project Summary
Development of Analytical
Methods for Specific Lawn-
Applied Pesticides in House
Dust
Marcia G. Nishioka, Hazel M. Burkholder, Marielle C. Brinkman,
and Sydney M. Gordon
The methods developed in this pro-
gram were designed for detection of
specific lawn-applied pesticides in
house dust and in polyurethane foam
(PDF) sleeves. PDF sleeves are used
in a dislodgeable surface residue col-
lection device, the PUF Roller. The
method developed for the herbicide
acids was applicable, as well, to the
analysis of pentachlorophenol and
2,4-dichlorophenol. The method de-
veloped for the dinitro-aniline herbi-
cides was also applied successfully
to the analysis of several thiophos-
phate insecticides and a chlorinated
fungicide.
Methods developed here provided
recoveries better than 80% at spike
levels that approximate house dust
levels. The methods incorporated sur-
rogate recovery standards and inter-
nal standards (for quantification) that
are tailored to the specific analyte
classes. This use of structurally simi-
lar surrogate recovery standards and
internal standards provides a greater
degree of confidence in the methods
when they are used for field samples:
the recovery of surrogates gives a
clear picture of the expected analyte
recovery. Structurally similar internal
standards compensate for the minor
chromatographic differences between
samples and standards and these
more accurately reflect the chroma-
tography of the analytes.
The methods that were developed
are rigorous and rugged, and per-
formed well when applied in field stud-
ies of simulated track-in of lawn-
applied pesticides into the home.
Recoveries of surrogate recovery stan-
dards were generally greater than 90%
in these studies.
This Project Summary was developed
by EPA's National Exposure Research
Laboratory, Research Triangle Park, NC,
to announce key findings of the re-
search project that is fully documented
in a separate report of the same title
(see Project Report ordering infor-
mation at back).
Introduction
House dust appears to be a long-term
sink within the home for pollutants, in gen-
eral, and pesticides, in particular. Scien-
tists, and now homeowners, are interested
in the concentrations of hazardous pollut-
ants adsorbed on house dust. Young chil-
dren appear to ingest significant quanti-
ties of dust while crawling and playing on
carpeted surfaces. With their less sophis-
ticated immune systems and high degree
of developmental change, younger chil-
dren may be at greater risk to ingestion of
contaminated dust than older children or
adults.
House dust is a more complex matrix
than soil or plant material. Debris from
human skin and human activities (e.g.
food, household cleaners) combined with
combustion source-derived pollutants will
be encountered in the house dust. Poten-
tial chemical interferences in the analysis
of pesticides in dust include, but are not
limited to, fatty acids, lipids, phenols, poly-
cyclic aromatic hydrocarbons, and carpet
additives. The ease in applying standard
soil analysis methods to house dust
samples for outdoor-applied pesticides will
be compromised further by pesticide lev-
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els that are expected to be significantly
lower due to the dilution that occurs dur-
ing any migration process. Therefore,
methods suitable for outdoor levels are
unlikely to be suitable for lower indoor
levels in a specific matrix like house dust.
Results and Discussion
Two different analyte derivatization
methods were developed and used on
this program, methylation with diazo-
methane and pentafluorobenzyl bromide
(PFBBr) derivatization. Methylation of
analytes with at least two chlorines pro-
vides sufficient sensitivity for detection by
GC/ECD (gas chromatography with elec-
tron capture detection) of mid to low ppb
concentration levels. Detection limits for
the mono-chloro phenoxy herbicide acids
can be as much as a factor of 1000-fold
higher, compared to the di-chloro phe-
noxy herbicide acids, with methylation and
GC/ECD analysis. PFBBr derivatization
offers the possibility of detection with en-
hanced sensitivity for these mono-chloro
herbicide acids.
The analyte spike levels for studies
involving methylation spanned a concen-
tration range of 1000. Despite this wide
concentration range, very similar recover-
ies were achieved for all analytes; recov-
eries were generally >85%. As seen from
the study of recovery from PUF, the re-
covery of the 2,4-D sodium salt was only
slightly less than the recovery of the 2,4-D
free acid. We conclude that these meth-
ods are useful for recovery of herbicide
salts that are typically applied to turf. For
analyses using the PFBBr derivatization,
the spike levels of the analytes were iden-
tical and recoveries were similar (>85%).
Conclusions
Methods developed here provided re-
coveries better than 80% at spike levels
that approximate house dust levels. The
methods incorporated surrogate recovery
standards and internal standards (for quan-
tification) that are tailored to the specific
analyte classes.
The methods that were developed were
rigorous and rugged, and performed well
when applied in field studies of simulated
track-in of lawn-applied pesticides into the
home. Recoveries of surrogate recovery
standards were generally greater than 90%
in these studies.
Sonification was shown to be useful for
extraction of both acidic herbicides and
polar dinitro-aniline herbicides. This ap-
proach was rapid and eliminated the need
for solvent-intensive Soxhlet extraction.
Extraction of PUF sleeves by manual
squeezing of the PUF in a polyethylene
zip-lock bag was shown to be an efficient
method for obtaining an extract of trace
dislodgeable surface residues.
Due to the complexity of the house dust
matrix, cleanup procedures had to be de-
veloped with each method. With sample
extract cleanup, analyses could be per-
formed using relatively low-cost, automated
GC/specific detector analyses, rather than
higher-cost, GC/MS analyses. The cleanup
procedures also reduced significantly the
organic burden placed on GC columns,
thus prolonging their lifetime and enhanc-
ing their performance. Solid phase extrac-
tion with disposable prepacked cartridges
was shown to be an effective and efficient
method of cleanup. Additional liquid parti-
tion steps were used as necessary.
Analyses of nine residential house dust
samples for herbicide acids and penta-
chlorophenol were carried out using the
designated extraction and cleanup meth-
ods and both GC/ECD and NCI GC/MS
analyses. These analyses showed good
agreement in quantification between the
two techniques, and no detectable inter-
ferences to the analytes of interest.
Recommendations
We recommend a further method
development effort for the analyses of
glyphosate in house dust. Degradation in
GC column performance and/or detector
performance was found with the method
developed, indicating the need for devel-
opment of an additional sample cleanup
technique.
This report was submitted in partial ful-
fillment of Contract No. 68-DO-0007 by
Battelle under the sponsorship of the U. S.
Environmental Protection Agency. This
work was conducted during the time pe-
riod of October 1991 to September 1993,
and was completed as of April 30, 1993.
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Marcia G. Nishioka, Hazel M. Burkholder, Marielle C. Brinkman and Sydney M.
Gordon are with Battelle, Columbus, OH 43201.
Robert G. Lewis is the EPA Project Officer (see below).
The complete report, entitled "Development of Analytical Methods for Specific Lawn-
Applied Pesticides in House Dust," (Order No. PB9; Cost: $25.00, 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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EPA/600/SR-97/110
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