United States      Prevention, Pesticides     EPA712-C-96-267
          Environmental Protection    and Toxic Substances     February 1996
          Agency        (7101)
&EPA    Occupational and
          Residential Exposure
          Test Guidelines
          OPPTS 875.2100
          Foliar Dislodgeable
          Residue Dissipation

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                           INTRODUCTION
     This  guideline is  one of a series of test guidelines that have been
developed by the Office  of Prevention, Pesticides and Toxic Substances,
United States Environmental  Protection Agency for use in the testing of
pesticides and toxic substances, and the development of test data that must
be submitted to the Agency for review under Federal regulations.

     The Office of Prevention, Pesticides and Toxic Substances (OPPTS)
has  developed  this guideline through a process of harmonization that
blended the testing  guidance  and requirements that  existed in the  Office
of Pollution Prevention  and  Toxics (OPPT) and appeared in  Title 40,
Chapter I,  Subchapter  R of the Code of Federal Regulations (CFR), the
Office of Pesticide Programs (OPP) which appeared  in publications of the
National Technical  Information Service (NTIS) and the guidelines pub-
lished by  the Organization for Economic Cooperation and Development
(OECD).

     The purpose of harmonizing these  guidelines  into a single  set of
OPPTS guidelines is to minimize  variations among the testing procedures
that must be performed to meet the data requirements of the U. S. Environ-
mental Protection Agency under  the  Toxic Substances  Control  Act (15
U.S.C. 2601) and the Federal Insecticide, Fungicide and Rodenticide Act
(7U.S.C.  I36,etseq.).

     This  guideline, along with the others in  Series 875.2000  through
875.2900, is being substantially revised for publication in 1997. However,
the current guidelines  are  still official. Before  initiating any studies for
post-application exposure registrants should contact EPA's Occupational
and Residential Exposure Branch (within the Office of Pesticide Programs)
at 703-305-6094.

     Final Guideline Release: This guideline is available from the U.S.
Government Printing Office, Washington, DC 20402 on The Federal Bul-
letin   Board.   By  modem   dial  202-512-1387,  telnet   and  ftp:
fedbbs.access.gpo.gov     (IP     162.140.64.19),     internet:     http://
fedbbs.access.gpo.gov,  or call 202-512-0132 for disks  or paper copies.
This guideline is also available electronically in ASCII and PDF (portable
document format) from the EPA  Public Access Gopher (gopher.epa.gov)
under the heading "Environmental Test Methods and Guidelines."

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OPPTS 875.2100   Foliar dislodgeable residue dissipation.
     (a) Scope—(1) Applicability. This guideline is intended to meet test-
ing requirements of the Federal Insecticide, Fungicide, and Rodenticide
Act (FIFRA) (7 U.S.C. 136, et seq.).

     (2) Background. The source material used in developing this har-
monized OPPTS test guideline is OPP guideline 132. This guideline should
be used with OPPTS 875.2000 and 875.2900.

     (b) Purpose. Requirements of 40 CFR 158.390 described in this sec-
tion  are confined to the measurements of pesticide residues which are de-
posited on and remain on  surfaces after pesticide application. These sur-
faces are limited to those that can be touched or disturbed by people, and
from which residues can be dislodged during the performance of various
tasks and  subsequently deposited on human skin and clothing or inhaled.

     (c) Test standards—(1)  Test substance.  A typical end-use  product
should be  used for this study.

     (2) Sites for conduct of tests.  Since  climate strongly influences the
dissipation of pesticide residues,  the applicant should perform dissipation
study at a site representative  of the climatic conditions  expected in the
intended use areas. The  Agency will provide guidance on the  choice of
site upon request.

     (3) Substitutions for sites. In certain cases, data from one site (when
available)  may be substituted for data from another site when  surface char-
acteristics are generally similar or nearly identical (e.g., orange and grape-
fruit orchard applications). For those cases, available residue data should
demonstrate that dissipation rates at the two sites do not differ significantly
for similar use patterns.

     (4) Method of application. The test substance should be applied by
application methods recommended for the end-use  product. Application
of the test substance to  the site, area,  or objects should  be at the least
dilution and highest rate permitted for that end-use product.

     (5) Timing of application.  The test substance  should be applied at
the time of year or season that would normally be recommended to  achieve
satisfactory pest control by the product.

     (6) Meteorological conditions. Daily meteorological conditions at or
near the site of application should be recorded as part of the data in this
study. Such data would include,  as appropriate, temperature, wind speed,
daily rainfall, humidity, and similar information.

     (7) Standards for sample collection—(i) Duplicate samples. Dupli-
cate  foliar samples should be collected periodically for the  development
of dissipation curves. The first samples should be taken  as soon as the
spray has  dried or the dust has settled. The intervals at the start of sampling

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should be relatively short and may increase with time. For example, sam-
ples taken as  soon as the  spray has dried or the dust has settled, and at
1, 2, 5, 7,  14, 21, 28, and  35 days after pesticide application would prob-
ably be appropriate for some pesticides.  Comparable control  or baseline
samples should be collected immediately before the pesticide application.
If analyses of samples reveal dislodgeable residues above the reentry level,
sampling and analyses should continue until a level at or below the reentry
level is reached.

     (ii) Additional standards  for soil samples. (A) Whenever the ap-
plied pesticide deposits on, is incorporated into, or diffuses into soil at
the site of application and whenever tasks at the treated  site will involve
exposure of workers  to large  amounts  of soil,  duplicate  soil samples for
pesticide residue analysis should be collected from the soil surface or from
not more than the upper 1 cm of soil in the test plot.

     (B) The fine material should be isolated from the soil samples without
grinding to give  all of the material having particle sizes of  147 (im or
less without particles larger than  147 (im.  The fine material will be ex-
tracted for residue analysis.

     (iii) Sample storage.  Samples and sample  extracts may be stored for
later analysis  only if fortified controls are  included to permit evaluation
of possible residue deterioration during storage. Such samples should be
stored under conditions which will minimize deterioration.

     (8)  Procedures  for chemical  extraction  and   analysis.  The
dislodgeable pesticide residues should be extracted from the foliar material
and soil, isolated from interfering materials by suitable cleanup procedures,
and quantified.

     (d) Reporting of test results. In addition to meeting the general re-
porting requirements of 40 CFR 158.390, the test report should also meet
the following  requirements: For  surface residues such as foliar residues,
the  analytical results should be  expressed  in terms  of milligrams  or
micrograms of residues per square centimeter of surface (e.g. leaf surface).
It will be necessary to estimate the surface area of extracted leaves that
are too small for a standard leaf punch to be  used.

     (e) Evaluation and use of data. Data obtained from this study are
for the development of dissipation curves which  can be used in the calcula-
tion of reentry intervals according to the  approaches described in OPPTS
875.2900.

     (f) References. The following references should be consulted for ad-
ditional background material on this test guideline.

     (1) Gunther,  F.A. et al. Establishing dislodgeable pesticide residues
on  leaf surfaces.  Bulletin of  Environmental  Contaminant  Toxicology

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9:243-249 (1973). This reference includes discussions of sampling proce-
dures and a description of leaf punches used in sample collection.

     (2) Iwata, Y. et al. Worker reentry into pesticide treated crops. I. Pro-
cedure for the determination of dislodgeable  residues on foliage. Bulletin
of Environmental Contaminant Toxicology 18:649-655  (1977).  This  is a
recent modification of the procedure referenced in paragraph (f)(l) of this
guideline for quantification of dislodgeable residues and increases the ap-
plicability of the method. Although additional research may uncover other
methods more predictive of the  respiratory and dermal dose variable,  at
present these techniques are the most suitable for foliar residues.

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