United States Prevention, Pesticides EPA712-C-08-011
Environmental Protection And Toxic Substances October 2008
Agency (7101)
&EPA Fate, Transport and
Transformation Test
Guidelines
OPPTS 835.1410
Laboratory Volatility
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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 835.1410 Laboratory volatility
(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 163-2 Laboratory volatility studies, 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. Volatilization can be a major mode for the movement of pesticides from
treated areas. Volatility studies determine the potential of a pesticide to move into the air and off-
site. The laboratory volatility study provides a rate of volatilization and the resulting air
concentration under confined conditions. The vapors resulting from volatilization of some pesticides
can cause adverse effects to humans via inhalation exposure at sites of application or biological
effects in nontarget organisms at some distance from the treated site.
(c) General considerations. (1) The laboratory volatility study is performed for pesticides
with properties, e.g., vapor pressure and Henry's Law Constant, suggesting that volatility may be a
significant route of dissipation.
(2) Data from a laboratory volatility study are used to support end-use products intended for
terrestrial and greenhouse uses or for manufacturing-use products which may legally be used to
formulate such an end-use product.
(3) In view of methodological difficulties with the study of photodegradation in air, prior
consultation with the Agency regarding the protocol is recommended before the test is performed.
(d) Test method.—(1) Test substance. The test substance should be a typical end-use
product. The composition of the test substance should be determined, including the names and
quantities of known contaminants and impurities, as far as is technically feasible.
(i) If the applicant's product is an end-use product, the test substance should be a product
whose formulation is typical of the formulation category (e.g., wettable powder, emulsifiable
concentrate, etc.) to which the product belongs.
(ii) If the applicant's product is a manufacturing-use product which could be used to make an
end-use product, the test substance should be a product representative of the major formulation
category which includes that end-use product. If the manufacturing-use product is usually
formulated into end-use products comprising two or more major formulation categories, a separate
study should be performed with a typical end-use product for each such category.
(2) Test procedure. A laboratory study should be conducted to determine the actual rate or
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extent of pesticide volatilization from soil under controlled conditions.
(i) Protocol development. A number of published studies of pesticide volatility provide
useful information for protocol development. Kearney and Kontson (paragraph (f)(l)) use a
polyurethane foam trap and a potassium hydroxide trap to recover sequentially the parent compound
and degradation product from air. The laboratory methods employed by Spencer and Cliath
(paragraph (f)(2)) for determining volatilization of chemicals used in this study allow measurement
effects of several variables. The use of hexane as a trapping medium limits the gas flow rates and
volumes that can be used. A study by Spencer et al (paragraph (f)(3)) describes use of polyurethane
foam traps and GLC detection largely specific for the compounds of interest. Specific detection
avoids interference that may cause falsely high vapor levels in field testing. Volatilization studies
call for methods for the trapping, extraction, cleanup, and quantitation of pesticides. A review of
reported methods for laboratory investigations of pesticides in air can be found in Lewis (paragraph
(ii) Laboratory experimental conditions should represent, to the extent possible, an
environment where the pesticide is intended for use.
(iii) The rate of test substance application to soil should approximate the intended rate of
field usage.
(iv) The following factors should be addressed in designing a laboratory volatility study:
(A) Properties of the pesticide such as vapor pressure, and water solubility, which can
influence the trapping medium and air sampling rates.
(B) Properties relating to the soil, such as adsorption to soil and soil texture, to avoid
untoward reduction of the rate of volatility (e.g., sandy soil is preferred). Soil from foreign sources
may be used, providing the foreign soil will have the same characteristics as soil in the United States
common to the proposed use area. Additional information on use of foreign soils may be obtained
from the document "Guidance for Determining the Acceptability of Environmental Fate Studies
Conducted with Foreign Soils," at the U. S. Environmental Protection Agency ' s Environmental Fate
and Effects Division, Office of Pesticides (see paragraph (f)(5)).
(C) Environmental factors, such as air temperature, humidity, and movement, to avoid
untoward dehydration or flooding of the soil and to assure efficiency of sampling
(v) Air samples should be collected and analyzed for residues in the laboratory experimental
equipment used. Monitoring should be conducted continuously or at intervals which increase with
time after the start of the experiment. Monitoring should continue until the nature of the residue
decline curve has been clearly established.
(e) Reporting and evaluation of data. Reporting units should be in the metric system, but
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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, (i) The test substance should be identified including chemical name and
percentage of active ingredient, molecular structure of the active ingredient, qualitative and
quantitative description of the chemical composition, and the names and quantities of known
contaminants and impurities;
(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 laboratory test equipment used, and photographs
or detailed descriptions of nonstandard equipment.
(5) Soils. Soils used should be characterized as to texture (percent sand, silt, and clay),
percent organic matter, moisture content, pH, cation exchange capacity, and bulk density (under
field conditions.
(6) Volatility. Volatility data expressed as ug/cm2/hour.
(7) Air concentrations. Air concentrations expressed as ug/m3 or mg/m3.
(8) Vapor pressure. Vapor pressure expressed as torr or the equivalent expressed in other
conventional units.
(9) Temperature. Temperature and relative humidity.
(10) 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 background
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information on this guideline:
(1) Kearney, P.C., and A. Kontson. 1976. A simple system to simultaneously measure
volatilization and metabolism of pesticides from soil. J. Agr. Food Chem. 24:424-426.
(2) Spencer, W.F., and M.M. Cliath. 1974. Factors affecting vapor loss of trifluralin
from soil. J. Agr. Food Chem. 22: 987-991
(3) Spencer, W.F., T.D. Shoup, M.M. Cliath, WJ. Farmer and R. Haque. 1979. Vapor
pressure and relative volatility of ethyl and methyl parathion. J. Agr. Food Chem. 27:273-278.
(4) Lewis, R.G. 1976. Sampling and Analysis of Airborne Pesticides. Pp. 51-94 in Air
Pollution from Pesticides and Agricultural Processes. R.E. Lee (ed.). CRC Press, Inc.
Cleveland, Ohio.
(5) U.S. Environmental Protection Agency (2006). Guidance for Determining the
Acceptability of Environmental Fate Studies Conducted with Foreign Soils. Environmental Fate
and Effects Division, Office of Pesticide Programs, USEPA. Washington DC. This document
can be found at: http://www.epa.gov/oppefedl/ecorisk_ders/soils_foreign.htm
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