United States Prevention, Pesticides EPA 712-C-98-112
Environmental Protection and Toxic Substances March 1998
Agency (7101)
&EPA Spray Drift Test
Guidelines
OPPTS 840.1200
Spray Drift Field
Deposition
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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 submittedby 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.).
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), 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's World Wide Web
site (http://www.epa.gov/epahome/research.htm) under the heading "Re-
searchers and Scientists/Test Methods and Guidelines/OPPTS Harmonized
Test Guidelines."
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OPPTS 840.1200 Spray drift field deposition.
(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 202-1—Drift field evalua-
tion (Pesticide Assessment Guidelines, Subdivision R: Pesticide Spray
Drift Evaluation, EPA Report 540/9-84-002, April 1984).
(b) General—(1) Purpose. Drift field deposition studies are per-
formed to determine the influence of a number of equipment and formula-
tion parameters and environmental factors on the dispersal of the formu-
lated pesticide from the application equipment to the intended surface(s).
The major parameters that will be tested are type(s) of nozzle, orientation
to the wind shear, formulations, cross-wind velocity and evaporative fac-
tors. Drift field evaluation involves commercial equipment to determine
the extent of drift expressed as concentration vs. distance. These normally
are measured under so-called worse case equipment and environmental
conditions.
(2) Test standards. In addition to the test standards set forth in
OPPTS 840.1000, the following test standards apply:
(i) Test substance—(A) End-use product. A formulated end-use
product of the same formulation category as the end-use product to be
registered, i.e. wettable powders, emulsifiable concentrates, etc., and use,
i.e. herbicide, insecticide, etc., will be tested. Use of dyes or other indica-
tors with the pesticide are acceptable only if these materials do not inter-
fere with chemical analysis or bioresponse, do not alter chemical or phys-
ical properties of the diluted spray, do deposit in direct proportion to con-
centrations of active ingredients, and do remain stable until analysis.
(B) Tank mixes and package mixes. Drift data requirements for each
package mix, and for each tank mix allowed in labeling are identical to
those requirements for any single pesticide applied alone, i.e the droplet
spectrum and swath displacement should be evaluated. Alternatively, the
swath displacement data for the mixture may not be required if the mixture
activity spectrum, droplet size spectrum, and physical data are sufficiently
similar to such data characterizing the mixture's most phytotoxic single
component for which acceptable swath displacement data have been sub-
mitted.
(ii) Dosage levels. Maximum label-recommended pesticide dosages
should be evaluated in all spray drift field evaluations.
(iii) Study location. The site should be typical in geography, topog-
raphy, season, and meteorology of those sites within intended use patterns.
The use of two or more topographically and meteorologically diverse sites
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is recommended in order to ascertain the effects of these variables on spray
drift. The evaluation should preferably be performed in a field or fields
having foliage or crop cover conditions similar to actual use conditions.
Open fields (not runways) may be acceptable only for evaluation of pes-
ticides to be applied directly to soil or to just-emerging plants. If it is
felt that barren fields should be used to test a product where vegetation
would exist according to the label recommendations, the justification
should be submitted to indicate the reason for this test modification.
(iv) Collection surface placement. (A) Collection surfaces for fallout
sampling should be located:
(7) Within the target area, at least one swath width upwind, and at
known distances outside the target area downwind to a minimum of 1,000
ft (300 m) for aerial and air carrier applications and 500 ft (150 m) for
other ground applications (including sprinkler irrigation systems).
(2) In a straight line approximately parallel to a stable wind direction
and as close as possible to the perpendicular of and centered to the direc-
tion of travel for the application equipment.
(3) At the soil surface or, if vegetation is present, at a level which
corresponds to the height of the surrounding canopy.
(B) Air samplers, such as a high volume type (20-50 ft3/min), should
be placed at a 2- to 3-m height at at least three down wind collection
stations (for example, at 200, 600, and 1,000 ft (60, 80, and 300 m) down-
wind) to sample airborne particles of the chemical. The filters on the air
samplers should be changed frequently in order to minimize stripping of
pesticide from the filter.
(C) While lateral distances between collection stations are left to the
discretion of the applicant, it is important that a sufficient number of col-
lection stations be established to present a definitive uninterrupted picture
of deposits across the treated swath as well as outside the target area.
Location of collection stations is particularly critical in areas where deposi-
tion rates are expected to change rapidly over a small lateral distance.
(v) Protocols. (A) Spray drift evaluation data from one or more appli-
cations to a single swath line are acceptable. Multiple applications (passes)
to a single swath are preferred. Full-field applications can be made. When
bioassays are used in the swath displacement test, multiple passes over
the same swath may be made only if the bioassay organisms are no closer
than one swath width downwind. The length of the treated swath should
be such that the spray cloud, if extended, would pass over the most distant
downwind collection devices, taking into account the probability that wind
direction may not coincide perfectly with the line of collection points. Nor-
mally the spray line should equal the sampling line length, that is, the
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spraying line should be 1,000 ft in length if the downwind sampling line
is 1,000 ft.
(B) At least one study should be conducted using equipment, equip-
ment adjustment and operation, procedures, and conditions most conducive
to drift as would be allowed in labeling, and as determined in part from
droplet spectrum tests. As an example, evaluate the spray drift using the
following parameters that would be permitted in normal application prac-
tices: Maximum recommended nozzle height (from the ground), nozzle
pressure, crosswind velocity, temperature gradient at the canopy and 2 m
above it, ground speed of the equipment, pesticide dosage, and airstream
sheer force (nozzle discharge orientation to air stream); minimum rec-
ommended nozzle orifice diameter, spray volume, and relative humidity;
and using cores or any other devices to increase droplet dispersion or
produce sheets, fans, or cones.
(c) Data reporting. The registrant's report on spray drift field deposi-
tion should include all information necessary to provide: A complete and
accurate description of the treatments and procedures; sampling data; data
on storage of the samples until analysis (if performed); any chemical anal-
ysis of the collection surfaces as to chemical content (if performed); recov-
ery efficiency; reporting of the data, rating system and statistical analysis;
and quality control measures/precautions taken to ensure the fidelity of
the operations. Specifically, each report should include the following infor-
mation:
(1) General, (i) Cooperator or researcher (name and address), test
location (county and state; country, if outside of the U.S.A.), and date
of study.
(ii) Name (and signature), title, organization, address and telephone
number of persons responsible for planning/supervising/monitoring.
(iii) Trial identification number.
(iv) Quality assurance indicating: control measures/precautions fol-
lowed to ensure the fidelity of the droplet size; record-keeping procedures
and availability of logbooks; skill of the laboratory personnel; equipment
status of the laboratory; degree of adherence to good laboratory practices;
and degree of adherence to good agricultural practices for application of
pesticides.
(v) Other information the registrant considers appropriate and relevant
to provide a complete and thorough description of the test procedure and
results.
(2) Control data. Control values for the test should be reported. Due
to the wide diversity of pesticide properties, use patterns, and organisms
exposed in the field environment, specific reporting requirements for con-
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trol values (as to source, sampling regime, and total number of sample
data submitted) will depend upon the complexity and variability of the
environment in which the test is to be conducted.
(3) Test substance and physical properties, (i) Identification of the
pesticide active ingredient including chemical name, common name
(ANSI, BSI, ISO, WSSA), and company developmental/experimental
name.
(ii) Active ingredient percentage by weight in the formulated end-
use product used or substituted (with reasons for substitution of end-use
product).
(iii) Type of formulation (e.g., emulsifiable concentrate, flowable
powder, liquid, etc.). Product formulation used, diluent and manner of dilu-
tion, mixtures, adjuvants, and their physical properties (surface tension,
viscosity, density, vapor pressure, etc.).
(iv) Dosage of active ingredients or acid equivalent per unit area of
land or gallons-per-minute (gpm) or liters-per-minute (1pm). The con-
centration of the final diluted spray mixture (in the spray tank) should
be sampled, chemically analyzed, and reported.
(v) If droplet size distribution is determined during the field evalua-
tion, physical property data, including droplet size, viscosity, density,
vapor pressure, visco-elasticity, and surface tension, should be determined
and reported.
(4) Test method. Each report should contain a statement regarding
the test method used with a full description of the experimental design
and procedure and including.
(i) Identification of the use of dyes or other indicators.
(ii) Identification of adjuvants used and other tank mix pesticides.
(5) Collection surfaces, (i) Identification of the collection surfaces.
The collection surfaces may include collection cards (flat horizontal or
vertical surfaces), air samplers or other devices by which droplet size dis-
tribution can be measured as necessary, and the down-wind pesticide
movement can be quantified.
(ii) Identification of the number of replicates.
(iii) Identification of the placement of the collection surfaces with
respect to the vegetation canopy or other anticipated surfaces, treated area,
and wind direction.
(6) Site of the test, (i) Site description of the drift field evaluation
such as type of forest, field, or grove.
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(ii) Climatological data (records of applicable conditions for the type
of site, i.e, temperature, air thermoperiod, rainfall or watering regime,
photoperiod, air velocity and wind direction, relative humidity).
(iii) Field layout (graphic display is encouraged).
(7) Application equipment, (i) The nozzle type, orifice size, and core
identification.
(ii) The nozzle pressure and flow rate.
(iii) The nozzle discharge orientation to the airstream. Nozzle dis-
charge orientation should be designated in degrees related to the direction
of travel of the spray equipment. Zero degrees indicates a horizontal nozzle
discharge pointing rearward (opposite to the equipment direction of travel),
90* indicates a vertical nozzle discharge pointing downward, and 180* in-
dicates a horizontal nozzle discharge pointing forward (with the equipment
direction of travel).
(iv) The estimated minimum and maximum nozzle-to-target height.
(v) Air velocity past the nozzle.
(vi) Descriptions of techniques and size determination devices.
(vii) Particle size distribution vs. cumulative percent volume and par-
ticle size distribution vs. droplet number (frequency) (an attempt should
be made to determine the droplet size distribution where droplet formation
is finalized).
(8) Additional information. If droplet size distribution is determined
during the field evaluation, the following information should also be sub-
mitted:
(i) A diagram of the plot indicating north, swath width, and orienta-
tion, and location and spacing of the collection stations.
(ii) Temperature at two levels, wind velocity and direction, variations
in velocity and direction during the application, relative humidity, atmos-
pheric pressure, and air stability. The latter is expressed as Barad's stability
ratio:
SR = [(Ts meters - TI meters)/(ave. wind velocity)2)] x 105
Temperature should be determined just above the canopy (Ti) and at least
2 m above that (T3) for all applications. A standard vertical separation
should be 2 m. Wind velocity should be determined at least 1 to 2 m
above the canopy height.
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(iii) Spray volume (liters per hectare or gallons per acre) and
carrier(s). The maximum and minimum carrier volumes recommended on
the label should be reported.
(iv) The ground speed of application equipment, the number of swaths
sprayed during exposure of collecting surfaces, and swath width.
(v) The quantity of active ingredients(s) or acid equivalent collected
or detected at each sampling point in terms of kilograms per hectare
(pounds per acre).
(vi) Adjuvant identification and dilution used.
(vii) The estimated minimum and maximum nozzle-to-target height.
(viii) Where droplet size distribution is determined during the field
evaluation, refer to OPPTS 840.1100 for the reporting requirements.
(9) Results. The quantity of active ingredients or acid equivalent col-
lected or detected at each sampling point in terms of kilograms per hectare
(or pounds per acre).
(10) Evaluation. The overall movement of the pesticide formulation
as a result of aerial transport.
(d) Exposure assessment. Employing the field evaluation data pro-
vided in paragraph (c) of this guideline, the registrant should make an
exposure assessment with respect to the quantity of pesticide to which
nontarget organisms including humans may be exposed. Comparison of
the toxicity data from studies conducted for plants, animals, or humans
to the exposure that may occur may be made as a part of an overall risk
assessment for nontarget organisms and humans. The assessment should
apply primarily to the nontarget areas adjacent to the intended application
sites.
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