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
      BULK RATE
POSTAGE & FEES PAID
         EPA
   PERMIT NO. G-35
Official Business
Penalty for Private Use $300
EPA/600/SR-97/110

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