United States Prevention, Pesticides EPA712-C-08-023
Environmental Protection And Toxic Substances October 2008
Agency (7101)
&EPA Fate, Transport and
Transformation Test
Guidelines
OPPTS 835.6400
Combination and
Tank Mixes
Field 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
(OPPTS), United States Environmental Protection Agency for use in the testing
of pesticides and toxic substances, and the development of test data to meet the
data requirements of the Agency under the Toxic Substances Control Act (TSCA)
(15 U.S.C. 2601), the Federal Insecticide, Fungicide and Rodenticide Act
(FIFRA) (7 U.S.C. 136, et seq.), and section 408 of the Federal Food, Drug and
Cosmetic (FFDCA) (21 U.S.C. 346a).
OPPTS developed this guideline through a process of harmonization of
the testing guidance and requirements that existed for the Office of Pollution
Prevention and Toxics (OPPT) in Title 40, Chapter I, Subchapter R of the Code
of Federal Regulations (CFR), the Office of Pesticide Programs (OPP) in
publications of the National Technical Information Service (NTIS) and in the
guidelines published by the Organization for Economic Cooperation and
Development (OECD).
For additional information about OPPTS harmonized guidelines and to
access this and other guidelines, please go to http://www.epa.gov/oppts and
select "Test Methods & Guidelines" on the left side menu.
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OPPTS 835.6400 Combination and tank mixes field dissipation
(a) Scope—(1) Applicability. This guideline is intended for use in meeting testing
requirements of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) (7 U.S.C. 136, et
seq.). It describes procedures that, if followed, would result in data that would generally be of
scientific merit for the purposes described in paragraph (b) of this guideline.
(2) Background. The source materials used in developing this OPPTS test guideline are
OPP 164-4, Dissipation studies for combination products and tank mix uses, OPP 160-4 General test
standards, and OPP 160-5 Reporting and evaluation of data (Pesticide Assessment Guidelines,
Subdivision N - Chemistry: Environmental Fate, EPA report 540/9-82-021, October 1982).
(b) Purpose. The objective of this study is to determine the dissipation characteristics of a
pesticide in soil when applied as a tank mix or in combination with other pesticides, whether in a
combination product or pursuant to labeling directions recommending the simultaneous or serial
application of two or more products. Information from these studies allows the Agency to ascertain
if overall soil persistence of pesticides is affected by the simultaneous or serial application of two or
more pesticides.
(c) General considerations—(1) Uses supported by study data. A laboratory or field soil
dissipation study supports the registration of an end-use product containing more than one active
ingredient intended for use as a component in tank mixtures, or customarily applied serially with
another pesticide product.
(2) Endangered species. Field studies should not be conducted in critical habitats or areas
containing or suspected to contain endangered or threatened plants or animals that may be threatened
by the test to be conducted.
(d) Test method—(1) Test substance, (i) For studies on combination products, if the end-
use product contains two or more active ingredients (combination product), the test substances
should be the end-use product and similarly formulated products containing each active ingredient
singly.
(ii) For studies on tank mixtures, if the use directions state that two or more end-use products
containing different active ingredients may be applied as a tank mixture, the test substances should
be the mixture of the end-use products prepared in accordance with the label directions, and each
separate end-use product.
(iii) For studies or serial applications, if the use directions state that two or more end-use
products containing different active ingredients may be applied serially, the test substances should
consist of the two or more end-use products to be used in the sequence specified in the label
directions.
(2) Application. The test substance(s) should be applied at the highest rate recommended by
product labeling and as follows:
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(i) For combination products, apply the test substances at the label-recommended field
application rates to both light and heavy-textured soils. Incorporate the test substances into the soil if
recommended by label directions.
(ii) For tank-mixed pesticides, apply the test substances at the label-recommended field
application rates to both light and heavy-textured soils. Incorporate each test substance into the soil
if recommended by label directions.
(iii) For serially-applied pesticides, apply the test substances individually and as the
sequential combination at the label-recommended field application rates to both light- and heavy-
textured soils. Incorporate each test substance into the soil if recommended by label directions.
(3) Soil sampling. Soil from the treated area or laboratory container should be sampled
following treatment for the purpose of ascertaining the extent of pesticide dissipation.
(i) Soil samples obtained from the intended site(s) of application or from the laboratory
containers immediately prior to application of the test substance should be used as experimental
controls.
(ii) Sampling times should include pre-application, date of application, and immediate post-
application. In the case of multiple applications, only immediate post-application samples (and not
pre-application and date-of-application samples) are to be taken in addition.
(iii) Soil samples should be taken in increments to a depth of 15 cm, unless results of studies
on pesticide mobility indicate that the test substance is likely to leach into soil deeper than 15 cm.
(iv) If data on leaching indicate that the test substance is likely to leach into soil deeper than
15 cm, or if the pesticide is incorporated into soil deeper than 5 cm, samples should be taken to a
depth sufficient to include most of the leached pesticide.
(4) Test duration. Residue data should be collected until patterns of decline of the test
substance and patterns of formation and decline of degradation products are established in soil, or
for a maximum duration of six months, whichever occurs sooner.
(e) Reporting and evaluation of data. Reporting units should be in the metric system, but
the English system may be used in addition. The systems should not be mixed (e.g.,
kilograms/acre).
(1) Test method. A statement regarding the test method used, including a full description of
the experimental design and procedures.
(2) Test substance. The test substance should be identified including:
(i) Chemical name and percentage of active ingredient, molecular structure of the active
ingredient, and qualitative and quantitative description of the chemical composition, and the names
and quantities of known contaminants and impurities.
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(ii) Manufacturer and lot and sample numbers of the test substances.
(iii) Properties of the test substance, including physical state, pH, and stability.
(3) Control values. Due to the wide diversity of pesticide properties, use patterns, and
organisms likely to be exposed in the field environment, specific reporting elements for control
values (as to source, sampling regime, and total number submitted) will depend upon the complexity
and variability of the environment in which the test is to be conducted.
(4) Test equipment. A description of the test equipment used, and photographs or detailed
descriptions of nonstandard equipment.
(5) Water. Characteristics of water obtained from a use site should be reported (e.g., pH,
temperature, oxygen content, flow rate, and percent of suspended solids).
(6) Soils. Characteristics of soils/sediments should be reported, including texture (percent
sand, silt, and clay), percent organic matter, moisture content, pH, cation exchange capacity, and
bulk density (under field conditions).
(7) Protocol development. Kaufman et al (paragraph (f)(l)) contains procedures for the
effect of methylcarbamates on acylanilide herbicide residues in soil. J. Agr. Food Chem. 18:204-
206. Kaufman et al (paragraph (f)(2)) provides techniques for methylcarbamate inhibition of
phenylcarbamate metabolism in soil. J. Agr. Food Chem. 18:513-519.
(8) Analysis and identification of degradation products. Analysis and identification of
pesticide residues in field studies should be reported only for those degradation products that were
found to form in the laboratory studies. This position is taken because the purpose of field studies is
to derive levels of degradation products as a result of pesticide use under field conditions.
(9) Calculation and tabular, graphic information. The principal mathematical equations
used in generating and analyzing data, as well as representative calculations using these equations.
When rates of formation and decline of parent compounds or their degradates are reported in any
test, data should be expressed as amounts, concentrations, and corresponding percentages. Rate
constants, when appropriate, should be reported in conjunction with rate data. Tabular data, as well
as graphs for decline curves and soil sorption, should be submitted.
(f) References. The following references should be consulted for additional information on
this guideline:
(1) Kaufman, D.D., J. Blake, and D.E. Miller. 1971. Methylcarbamates affect acylanilide
herbicide residues in soil. J. Agr. Food Chem. 18: 204-206.
(2) Kaufman, D.D., P.C. Kearney, D.W. Von Endt, and D.E. Miller. 1970.
Methylcarbamate inhibition of phenylcarbamate metabolism in soil. J. Agr. Food Chem.18:513-
519.
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