United States Prevention, Pesticides EPA712-C-96-272
Environmental Protection and Toxic Substances February 1996
Agency (7101)
&EPA Occupational and
Residential Exposure
Test Guidelines
OPPTS 875.2900
Data Reporting and
Calculations
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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 875.2900 Data reporting and calculations.
(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 134.
(b) Nondetectable residue method—(1) When used. For purposes
of this section, a reentry interval is that time period beyond which there
are no detectable dislodgeable residues of the pesticide on surfaces to
which the pesticide was applied, as indicated by studies conducted as de-
scribed in OPPTS 875.2100 and 875.2200 of this guideline.
(2) Approach. Environmental samples may be collected periodically
until no residues are detected in three consecutive samplings using suitably
sensitive analytical techniques and equipment. Alternately, the applicant
may be justified in extrapolating a dissipation curve to the minimum de-
tectable levels. The interval for residue dissipation to the nondetectable
level would be proposed as the reentry interval. For reentry intervals deter-
mined according to this approach, exposure information described in
OPPTS 875.2400 and 875.2500 of this guideline are not required.
(c) Allowable exposure level method—(1) When used. For purposes
of this section, a reentry interval is that time period beyond which
dislodgeable residues on surfaces to which the pesticide was applied have
dissipated to the allowable exposure level (AEL) (or lower) as indicated
by studies described in OPPTS 875.2100, 875.2200, 875.2400, and para-
graph (b) of this guideline.
(2) Approach, (i) Calculation of a reentry interval according to the
criteria of paragraph (c)(l) of this guideline involves evaluation of data
to determine that level of residue in a reentry site which will result in
an amount of human exposure under specified human activities that is at
or less than an AEL. To make this evaluation, the applicant should use
two kinds of data:
(A) Data on the relationship between pesticide residue levels and total
human exposure during an eight-hour period.
(B) Data on the relationship between pesticide residue levels and
time.
(ii) For the approach outlined in paragraphs (c)(2)(i) of this guideline:
(A) The applicant will determine an AEL and described according
to OPPTS 875.2000, paragraph (h), based on the toxicity data required
by 40 CFR 158.340 and described by OPPTS Series 870 guidelines.
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(B) The applicant will examine human exposure data to determine
how much exposure (or what dose) a person would receive when perform-
ing activities (specific to the proposed use) in a treated area with specified
levels of residues. These data will enable the applicant to determine a re-
entry level (Rs) for a particular combination of human activity, crop, pes-
ticide formulation type, and site.
(C) Finally, the applicant will review residue dissipation curves to
determine how long after application it will take the residue levels to de-
cline to the reentry level in the particular study location, thus estimating
the reentry interval (Ts).
(D) The number of sampling units in the study and all assumptions
used in the calculations should be specified.
(d) Adjustment to reentry intervals—(1) When used. A registrant
or registration applicant may provide information to support an adjustment
of a reentry interval. Such information should be of one of the types de-
scribed in paragraphs (d)(2) through (d)(4) of this guideline.
(2) Adjustments based on toxicity studies. The animal toxicity stud-
ies described in OPPTS Series 870 guidelines may have been performed
using test substances of an end-use product or active ingredient in a sol-
vent. Solvents may aid in dermal absorption of the pesticides and/or may
increase their apparent toxicity. After application, such components of end-
use products may dissipate from the application site more rapidly than
the active ingredient. Testing of animals with the pesticide without sol-
vents may show that it is not as toxic as the original product. If there
are sufficient differences in toxicity or in residue retention after applica-
tion, the applicant may wish to submit data to support adjustment of a
reentry interval.
(3) Adjustments based on residue dissipation studies. In some
cases, established reentry intervals are based on data developed from stud-
ies of a site that may not adequately characterize residue dissipation at
another site because of regional and climatological differences, differences
in application methods, or differences in post-treatment methods and expo-
sure. These factors would likely affect the slope of the residue vs. time
curve. In such cases, additional data may be submitted to the Agency to
support an additional reentry interval.
(4) Adjustments based on human exposure studies. Data from
human exposure studies may indicate significantly different human expo-
sure levels because of widespread changes in agricultural practices or other
conditions. Such data may be submitted to support adjustment of the re-
entry interval.
(e) Early reentry: practices and limitations—(1) General. Local
conditions and activities may necessitate early reentry by individuals into
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treated areas before the reentry period has completely elapsed. Such activi-
ties may include posting, scouting, crop sampling, and similar related ac-
tivities, often of a brief and limited nature. Several practices may be nec-
essary to protect individuals who must undertake early reentry. Some of
these are described below. Consultation with local agricultural experts is
generally recommended before early reentry is undertaken.
(2) Reduction of site residues. Site residues may be reduced to re-
entry level by rainfall or artificial means, such as spraying the site with
water. Data on residue reduction by rainfall or equivalent spray washing
(as in overhead irrigation) may be submitted to support early reentry. In
those cases, early reentry may be granted to allow people to enter treated
sites before expiration of the reentry interval.
(3) Use of personal protective equipment. Early reentry may be
granted to allow people to enter treated sites before expiration of the re-
entry interval by use of personal protective equipment, such as protective
clothing and appropriate respirators. The personal protective equipment
should be appropriate for the pesticide residue levels at the site at the
time of reentry and should conform to any existing protective standards
(such as those established by OSHA). Data on the reduction of human
exposure to residues by use of personal protective equipment should be
submitted and support that the personal protective equipment would reduce
human exposure to the AEL and would be likely to be used.
(4) Reduced exposure times. The reentry level is based on residue
exposures representative of normal reentry activities for an 8-hour day.
In circumstances where only respiratory exposure to airborne residue will
occur, early reentry may be allowed for shorter periods at residue levels
higher than the reentry level. The excursion factors described in the
Threshold Limit Values (TLV) booklet of the American Conference of
Governmental Industrial Hygienists (ACGIH) may be used. Excursion fac-
tors allow shorter exposures to chemicals at levels higher than the TLV
or OSHA's Permissible Exposure Limit. This approach requires that the
exposure level be within an acceptable excursion range and that the prod-
uct of the concentration multiplied by the exposure time does not exceed
the product of the TLV concentration multiplied by 8 hours. Such excur-
sion factors are applied only to chemicals which do not have established
ACGIH "ceiling" designations. The ceiling designations indicate that the
TLV should not be exceeded.
(5) Residue level test kits. Early reentry may be allowed if field
test kits establish that residues have dissipated to reentry level prior to
expiration of the reentry interval. Data should be submitted to support the
use of field test kit systems for monitoring pesticide residue levels. Such
systems could include any of several chemical residue detection devices
or procedures that would readily indicate when residue levels of treated
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sites are greater or less than the AEL. (For this factor, the adjustment
could either extend or shorten the reentry interval.)
(f) References. The following references should be consulted for ad-
ditional background material on this test guideline. The following publica-
tions report procedures for the analysis of organophosphorus pesticide resi-
dues in the worker environment suitable for rapid tests in agricultural sites.
(1) Smith, C.A., F.A. Gunther, and J.D. Adams. 1976. Worker envi-
ronment research. III. A rapid method for the semiquantitative determina-
tion of some dislodgeable pesticide residues on citrus foliage. Bull. Envi-
ron. Contam. Toxicol. 15:305-310. [This paper reported the use of a device
for sampling foliar surface residues, and rapid methods for residue cleanup
and quantification of organophosphorus pesticide residues. The method de-
pends upon the generation of a color by reaction with 4(4-
nitrobenzyl)pyridine. ]
(2) Smith, C.A., and F.A. Gunther. 1978. Rapid estimation of
organophosphorus pesticide residues in citrus grove soil. Bull. Environ.
Contam. Toxicol. 19:571-577. [A procedure for field analysis of
organophosphorus pesticide residues sorbed to surface soil is reported in
this paper.]
(3) Berck, B., Y. Iwata, and F.A. Gunther. 1981. Worker environment
research: Rapid field method for estimation of organophosphorus insecti-
cide residues on citrus foliage and in grove soil. J. Agric. Food Chem.
29:209-216. [This paper is an elaboration of the studies in paragraphs
(f)(l) and (f)(2) of this guideline using different sampling methodology
and instrumentation. Procedures are reported for both foliar and soil resi-
dues.]
(4) Iwata, Y., J.B. Knaak, G.E. Carman, M.E. Dusch, and F.A. Gun-
ther. 1982. Fruit residue data and worker reentry research for chlorthiophos
applied to California citrus trees. J. Agric. Food Chem. 30:215-222. [This
paper reports dissipation data for a pesticide and its five toxic alteration
products and uses that data to estimate a reentry interval by the AEL and
the CDF A methods. The authors report that both methods give the same
reentry interval.]
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