United States      Prevention, Pesticides    EPA712-C-96-189
          Environmental Protection   and Toxic Substances    August 1996
          Agency        (7101)
&EPA    Residue Chemistry
          Test Guidelines
          OPPTS 860.1900
          Field Accumulation in
          Rotational Crops

     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

     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,    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."

OPPTS  860.1900 Field accumulation in rotational crops.
     (a) Scope—(1) Applicability. This guideline is intended to meet test-
ing  requirements  of both  the  Federal  Insecticide,  Fungicide,  and
Rodenticide Act (FIFRA) (7 U.S.C. 136, et seq.) and the  Federal, Food,
Drug, and Cosmetic Act (FFDCA) (21 U.S.C. 301, et seq.).

     (2) Background. The source material used in developing this har-
monized OPPTS test guideline is OPP 165-2. Field Accumulation Studies
on  Rotational Crops  (Pesticide Assessment Guidelines,  Subdivision  N,
Chemistry:  Environmental  Fate,  EPA  Report  540/9-82-021,  October
1982). This OPPTS guideline should be used in conjunction with OPPTS
860.1000, Background.

     (b) Purpose. Data from field accumulation studies on rotational crops
will enable the Agency to determine under actual field-use conditions the
amount of pesticide residue uptake in rotational crops. Such data are used
to establish realistic crop rotation restrictions  (time from application to
a time in which crops can be rotated) and to provide information for deter-
mining whether tolerances are needed in rotational crops.

     (1) General considerations, (i) Studies on confined rotational crops
and field rotational crops are conditionally required under 40  CFR part
158 for uses of pesticides on  food crops. A rotational crop use is  any
field-vegetable  crop use  or any other site use  on which it is reasonably
foreseeable  that any food or feed crop may be  planted after  harvest of
a treated crop.  The purpose  of field  studies is to determine the  amount
of pesticide residue uptake into  rotational crops. The study uses a typical
end-product applied to a field  plot. Results of these studies are used to
determine whether residues  occur  in rotational crops grown under actual
field conditions. Based on these  data,  appropriate  crop rotation restrictions
(time from application to planting of rotational crop) may be established
and the need for tolerances on the rotated crops determined.

     (ii) The Agency  has determined  that rotational  crop studies will not
be required for uses of pesticides  on the following  commodities  or crop
groups: Asparagus,  avocado,  banana, berries crop group, citrus  fruits crop
group, coconut, cranberry, dates,  fig, ginseng, globe artichoke,  grapes,
guava, kiwi fruit, mango, mushrooms, olives, papaya, passion fruit, pine-
apple,  plantain, pome fruits  crop group, rhubarb, stone fruits crop group,
and tree nuts crop group. Refer to 40 CFR  180.41  for complete lists of
the crops in each crop group.

     (2) Scientific considerations, (i) If the level of the total radioactive
residue (TRR) in the confined rotational crops is equal to or  exceeds 0.01
parts per million at the desired rotational interval or at 12  months,  and
once the nature of the residue in the rotational crops is understood, Reg-
istrants should consider the Agency's position regarding the residue to be
regulated in the primary crop  (see OPPTS 860.1850 and the  following

Figure  1) to decide whether the first tier of field trials  should be initiated.
That is, if the composition of the TRR in  the rotational crops is such that
residues which need to be are regulated are found at  levels  greater than
or equal to 0.01 ppm in the rotational crop (following the criteria set forth
in OPPTS 860.1300), field trials should be performed.  If residues  of con-
cern in the confined study are greater than or equal to 0.01 ppm but less
than the limit of quantitation (LOQ) of the analytical  method to be used
on field trial samples, the Agency will consider waiving the need for field
trials on a case-by-case basis.
   Figure 1.
                   Pesticide to applied to crept that on be rattled.

B) -ORES Hun
                               14-C Study- 1xApplication Rate
       <0.01 ppm In crap parts
       uasd lor toed/bed aa
       defined In Tabte I,
       at the desired plant-beck
       (12 months max).
      No tolerances required. A
      rotational crop restriction
      may be needed.
                                   £0.01 ppm In craps after 12 month
                                   pknHiack (or shortsr Interval <
                                                  (See QjkMkK 800.1300).
                            Residues of concsm are observed.
                                     Umtad FMd TrUs (Odd)
                  Residues of concern
                  at quantifiable levels.
                        Extended FMd Trials
 Tolerances Required
(See SukMlma«).1iOO].
nookjuss of concsm at non-
quanWIeble levels.

No tolerances required. Plant-fcack
                                          No tolerances required.
                                          Ptent-btck restriction maybe
     (ii) The limited field trials should be conducted on a representative
crop (as defined in 40 CFR 180.41) at two sites per crop for the following
three crop groups: Root and tuber vegetables,  leafy vegetables and  small
grains (wheat, barley, oats, rye) for a total of six trials. As with confined
studies (OPPTS 860.1850), soybeans may be substituted for the leafy  vege-
table.  The six trials should be  conducted on crops which a registrant in-
tends  to have  as  rotational crops on the label.  If there  is no uptake  of
residues of concern in one  or two of the representative crops in the con-
fined  study, the Agency  still requires six field trials. The trials may be
distributed at  the petitioner's  discretion  among  the representative  crops
showing uptake. In addition, some  of the six trials  could be conducted
using other crops that are typically involved in crop rotation such as alfalfa
and soybeans.

     (iii)  The  soil should  be treated at the maximum label rate and  the
maximum  number of applications  and the  appropriate crops  should be
planted after the minimum aging interval.  However,  if the  pesticide is only

to be applied to foliage, the treatment in the field studies may be carried
out in the same manner. The  crops  should be  harvested and all the plant
parts (including leaves of the root and tuber vegetables) prescribed as raw
agricultural  commodities (RACs)  in Table 1 of OPPTS 860.1000 should
be analyzed for the residues of concern observed in primary crops as well
as any other residues of concern specific to rotational  crops which fulfill
the criteria set forth in OPPTS 860.1850. Quantitation limits for rotational
crops should be comparable  to those for primary crops.  The petitioner
should describe how the values for the LOQ were calculated and cite any
appropriate references.

     (iv) The  methods  employed  to analyze  the  rotational crops should
be specific for all pesticide residues of concern in the subject commodities.
If the  analytical procedure determines interfering compounds it will  be
considered to be deficient  and this would be  a cause for rejection of the
studies. It would also be desirable to employ sites on which the test pes-
ticide had not  been previously applied. If residues are found in control
crop samples, the Agency will not  automatically reject the field studies.
The total study will be examined  and consideration given to factors such
as the relative levels of residues in treated and  control samples. As in
the case of the  confined accumulation in  rotational crops study,  analysis
of the soil is not required.

     (v) If no residues above the LOQ are observed in RACs in the limited
field trials,  no  tolerances will be  needed.  However plantback restrictions
will normally be needed unless the confined  study shows no residues of
concern at a 30-day plantback interval.

     (vi) If the  limited field studies in paragraph (b)(2)(ii) of this guideline
indicate that quantifiable residues will occur, rotational crop tolerances will
be required. The requirement for  number of trials would be the  same as
that to establish primary tolerances  on all crops  or crop groups  which a
registrant intends to have as rotational crops  on the label. If a registrant
desires to allow the universe of crops to  be rotated, magnitude of the resi-
due data are required on representative  crops (see 40 CFR  180.41) for
all crop groups which could be planted in a typical crop rotation sequence.
With  respect to treatment, these trials should be conducted in the same
manner as discussed in paragraph (b)(2)(ii) of this  guideline for the limited
trials. If a registrant believes  that fewer crops would be rotated because
of the nature of the pesticide or due  to the way it is used, guidance should
be obtained from the Agency regarding  specific data requirements in that
case. If tolerances exist on the crops to be rotated as a  result of a primary
use, rotational  data on these crops would be  required  only if residues in
rotated crops are significant in comparison to those in the primary crop.

     (c) Test standards—(1) Test substance. The test substance should
be a typical end-use  product. If more than one formulation type is reg-
istered, several  factors  need to be considered  as  to which types should

be used. If one formulation has a significantly higher application rate than
the others, it should be applied to the plots in which the rotational crops
will be grown. If all formulations have similar application rates but one
has been specifically designed to have a longer half-life in the environment
(e.g. controlled release product), the latter should be  the  test substance.
The discussion in OPPTS 860.1500  on formulations  for crop  field trials
should also be consulted. That guidance notes that for target crops, residue
data can be translated among formulations which are diluted in water and
applied early in the growing  season.  Such translation would also be appro-
priate for rotational crop  field studies.  Therefore, rotational crop data re-
flecting use of a wettable powder would cover formulations such as emul-
sifiable concentrates and water dispersible granules. However, as with tar-
get or primary crops,  separate studies will  normally be required on rota-
tional crops reflecting uses of granular  formulations unless data are avail-
able to  show the  relative soil half-lives of the active ingredient as a func-
tion of formulation.

     (2) Test procedure—(i) Sites.  Field accumulation studies should be
conducted on at  least two different  sites per crop.  These sites should be
representative of the areas where rotated crops are expected to be grown.
If possible,  the soil type at  one of the test  sites should be the  same as
that used in the  confined accumulation  study of  OPPTS  860.1850.  For
restricted  use patterns where only one typical area is  involved, data from
two similar sites should be submitted.

     (ii) Application.  (A)  The soil at the test site  should be treated with
the test substance applied by the method stated in the directions for use
specified on the product label and at the highest recommended label rate.
However, if the  pesticide  is only to be applied to foliage, the treatment
in the field studies may be  done in the same  manner.

     (B) Following treatment, the pesticide should be aged under aerobic
conditions in the  soil for a time approximating the  anticipated agricultural
practice (e.g.,  1 year for crops rotated the following year, 120  days  for
crops rotated  immediately after harvest, and 30 days  for  assessing  cir-
cumstances  of crop failure). Growing  a primary crop in the soil during
the aging period is not precluded.

     (iii) Sampling. (A)  Representative  root and  tuber vegetable, small
grain, and leafy vegetable crops should be planted as rotational crops. Soy-
beans may be substituted for the leafy vegetable.

     (B) If a registrant is  proposing  a tolerance for residues in a rotated
crop, that crop should be planted, harvested, and  analyzed for  residues
at test sites selected in accordance with the requirements described in detail
in OPPTS 860.1500.

     (C)  The rotational crop RACs (including the foliage of the root and
tuber vegetable) as prescribed in Table 1 of OPPTS 860.1000 should be
analyzed for residues at appropriate harvest times.

     (D)  Test duration. Residue data should be collected in rotational crops
until the  time that the mature portions of the crops are normally harvested.

     (d) Reporting and evaluation of data. In  addition to the applicable
reporting requirements  specified in OPPTS 860.1000, the  following  data
should be reported:

     (1) Field test data including:

     (i) Dates  of planting and harvesting of primary and rotational crops.

     (ii) Amount of rainfall and irrigation water (accumulated from appli-
cation to harvest).

     (iii) Temperature monitoring data and a description  of the  general
climatic conditions at the test site during the study.

     (iv) Planting, culture, and harvesting techniques.

     (v) Pesticide application dates and method.

     (vi) Sampling  techniques  for primary  (if applicable) and rotational
crop RACs.

     (vii) Stages of crop development at times of sampling.

     (viii) Weight of each sample taken for analysis.

     (2) Analysis for residues  of parent compound and metabolites in the
crops. Separate analyses should be conducted on different portions of the
plant as  outlined in Table 1 of OPPTS  guideline  860.1000.  In addition,
analysis  of both the aerial and root portions of root crops should be  con-

     (e) Format of data  report.  The following format is provided as an
example. Other  formats are acceptable provided that  all the  information
is included.

     (1) Title/cover page.  Title page and additional documentation require-
ments (i.e. for data submission and statement of  data confidentiality of
data) if relevant to the study  reported should precede the content of the
study. These requirements are described in PR Notice 86-5 (see paragraph
     (2) Table of contents. The table of contents  should follow the title,
data confidentiality, and GLP pages. This page should provide the overall
organization of the report, including tables and figures.

     (3) Abstract.  Give a summary of the study addressing the following

     (i) The chemical name and formulation of the pesticide and the meth-
od of application to the primary (treated) crop.  Structures of the pesticide
and metabolites may be included in this section.

     (ii) Maintenance of the treated plots.

     (iii) A narrative or a table (with  an appropriate title) that provides
the following information:

     (A) Days between treatment and planting of the rotational crops.

     (B) Age of crop (in days) at each sampling point (e.g. at forage, hay,
grain stages).

     (C)  Total  residues  in parts per million.  Parent  compound  and
metabolites of concern  should be  reported separately if so determined by
the method.

     (iv)  Indication of problems (such as technical  difficulties or unusual
weather) resulting in necessary deviations from the  intended test protocol.
Describe the effect of the deviations on the results  of the study.

     (v) The name and phone number of a contact  person should be pro-
vided in  the event the  reviewer has technical questions  about the  study.
(This is optional. However, providing this information will facilitate effi-
cient review in case of questions.)

     (4) Introduction. This  section should open with a description of the
purpose of the study, what requirement it is intended to satisfy, and (if
applicable) how it supports the position of the registrant. Background and
historical information relative to the study should appear in this section.

     (5) Materials/Methods.  This  section should  be in narrative form in
the following order and should contain  all details  with regard to the mate-
rials, equipment, experimental design, field plots and procedures used in
conducting the study. Registrants are encouraged  to include drawings and
photographs of the plot, equipment and of different phases of the  study.

     (i) Chemical. (A) Active ingredient and type of formulation.

     (B) Include  the percent (by weight) of the active ingredient and for
liquid formulations, the weight of the active ingredient per unit of liquid

     (ii) Site. (A) Include a map of the test plots  indicating their location,
topography and  size, and location and size of the control plots in relation
to the  test  plots; the soil characteristics (percent  sand, silt,  clay, and or-
ganic matter, pH, water holding capacity).

     (B) A complete record of daily temperature and daily rainfall through-
out the  study (refer to raw data discussion in OPPTS 860.1000) and how
they compare to average temperature and rainfall at the test site.

     (iii) Crop.  (A) Crop and pesticide use  history on  the plot for the
3-year period preceding the study.

     (B) The date and technique of plot preparation prior to pesticide appli-

     (C) The identity of the primary (treated) crop; a description of how
and when the primary crop was planted; how and when the subject pes-
ticide was applied; the weather (temperature, rainfall, windspeed and direc-
tion) and condition of the field at time of application;  the formulation of
the pesticide applied, adjuvants or other compounds added to  the spray/
application mixture; the application rate and the application  technique.
Also, provide a similar description for each of any additional applications
made of the subject pesticide. Indicate how  much pesticide was applied
in comparison  to  actual use rates;  and  if application  technique  differed
from label recommendations.

     (D) A description of any posttreatment crop maintenance such as use
of fertilizers and other pesticides, irrigation (when applied, how much, and
source), tilling, weeding, etc.

     (iv) Test method—(A) General. (7) Provide the  date of harvest of
the treated crop; describe what was done to the plot after harvest in prepa-
ration for planting of the rotational crops.

     (2) Provide the identity of the  rotational crops planted  in  the study;
a description of the procedure used in planting the rotational  crops;  and
days elapsed between planting of  crops  and treatment with pesticide; a
description of  all procedures used  in the maintenance of the rotational
crops (as done for the treated crop), the sampling/harvest method and num-
ber of samples/replicates.

     (3) Describe  handling from the time of taking of the samples  until
analysis with special attention  to the conditions under which the sampled
rotational  crops were stored and the thawing procedure (if frozen). Deter-
mine storage stability of pesticide residues. Provide dates the samples were
frozen, thawed, and analyzed.

     (4) Describe  any deviation from the intended test protocol  and the
effects on the results.

     (B) Analytical method.  (7) Describe methods fully (or reference if
previously submitted),  including method  validation data, recovery  and
method sensitivity data,  sample chromatograms,  and sample calculations.
Preparation and handling of the sample throughout the method should be
described in detail. Note that methods for metabolites may also be needed.

     (2) Identify instrumentation, equipment and reagents used and the op-
erating conditions of the instrumentation. If the extraction/clean-up proce-
dure is complex, a flow diagram should be submitted.

     (3) Identify  all plant fractions analyzed  in the study,  such as  grain,
forage, hay,  and straw in the case of  small  grains and root  and  aerial
(leafy) portions in the case of root crops.

     (6) Results/discussion,  (i) This section  should contain the scientific
results of the study, for instance:

     (A)  Narrative  and tables  describing the  steps taken in determining
the pesticide residues in crop samples. (Any graphical presentations  of the
data should be accompanied by the tables of the actual values from  which
the graphs were constructed.)

     (B) A table of structures and chemical names/designations for the par-
ent compound and metabolites.

     (C)  Total residues of concern for  all RACs  as prescribed in  Table

     (7) Conclusion. Provide discussion  as to the  significance of the resi-
dues (if any) taken up, at what  intervals residues are taken up by rotational
crops (in which  crop  fractions and at what levels) and at what interval
no  quantifiable residues of concern can be  expected to be taken  up by
rotational crops.

     (8) Certification. Include:

     (i) Signatures  of each  of the senior scientific personnel responsible
for the study.

     (ii)  Certification  by registrant that the  report  is a  complete  and
unaltered copy of the report provided by the testing facility.

     (9) Tables/figures. Use arabic numerals for figures and roman numer-
als for tables.

     (10) References.

     (11) Appendixes.  Reprints of methods and other  studies cited,  actual
results of analyses (raw data), copies of relevant  letters and memos and
other material not  fitting in any of the other sections and that support
the registrant's case should be placed in this section.

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

     (1) Environmental Protection Agency. Pesticide  Assessment Guide-
lines, Subdivision N, Chemistry: Environmental Fate,  Field Accumulation


Studies on Rotational Crops, Addendum 1, Series 165-2, EPA Report 5407
09-86-149, 1986.

    (2) Environmental Protection Agency. Pesticide Regulation Notice PR
86-5, Standard Format for Data Submitted under the FIFRA and Certain
Provisions of the Federal Food, Drug, and Cosmetic Act (FFDCA), May

    (3) Environmental Protection Agency. Pesticide Rejection Rate Anal-
ysis, Residue Chemistry/Environmental Fate: Followup Guidance for Con-
ducting Rotational  Crop Studies, EPA Report No. 738-B-93-001, Feb-
ruary 1993.