Document ID: EPA-HQ-OPP-2006-0874-0009
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2006-11-01T05:00Z

SEQ CHAPTER \h \r 1 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

OFFICE OF PREVENTION, 

PESTICIDES, AND TOXIC SUBSTANCES

PC Code: 098801

DP Barcode: 323824    

Date:  October 24, 2006

MEMORANDUM						

SUBJECT:	Review of Registrant Error Correction Comments on EFED
Reregistration Chapter for Chlorflurenol.

TO:	Tracy Perry, Chemical Review Manager

Special Review and Reregistration Division (7508P)

FROM:	Jennifer Leyhe, MS, Biologist

Larry Liu, PhD, Chemist

Environmental Risk Branch V

Environmental Fate and Effects Division (7507P)

APPROVED	

BY:	Mah Shamim, Branch Chief

Environmental Risk Branch V

Environmental Fate and Effects Division (7507P)

The Environmental Fate and Effects Division (EFED) has completed its
review of error correction comments received from the consultant
(Mandava Associates, LLC) that represents the registrant (Repar
Corporation), regarding the environmental fate and ecological risk 
assessment chapter in support of the chlorflurenol reregistration
decision.  The process used by EFED to evaluate exposure and the
potential risks associated with the uses of chlorflurenol is consistent
with that described in the Overview of the Ecological Risk Assessment
Process in the Office of Pesticide Programs.

Registrant comments are divided in to two sections, one section focusing
on environmental fate and the other focusing on ecological effects. 
Below, EFED addresses the registrant’s comments by first paraphrasing
the comment and then responding to the comment.

Environmental Fate Section

A.  Registrant’s Rebuttal on the Environmental Fate Data Requirements 

Registrant’s Rebuttal:

The registrant claimed that EPA had granted a low volume/minor use
exemption (LVE) and only required the following studies in the
environmental fate area:

161-1 Hydrolysis 

161-2 Photodegradation -Water 

162-1 Aerobic Soil Metabolism 

163-1 Leaching, Adsorption/Desorption 

Accordingly, the registrant reformatted the previously submitted data
which was in the EPA database.  The registrant submitted the reformatted
three studies [OPP Guidelines 161-1 (Hydrolysis study), 162-1 (Aerobic
soil metabolism study) and 163-1 (Leaching, adsorption/Desorption
study)] in 1992. The registrant submitted a protocol to EPA for OPP
Guideline 161-2 (Photodegradation study in water) and is awaiting the
Agency comments on the protocol.  The Agency reviewed the submitted data
only in 2006 and now issued the Data Evaluation Reports (DERs) for the
four environmental fate studies [OPP Guidelines 161-1, 162-1 and
163-1(a) and (b)]. The Agency's determination of the acceptability of
these studies is shown below: 

161-1 Hydrolysis - Supplemental 

163-l(a) Leaching - Supplemental 

163-l(b) Adsorption/Desorption - Supplemental 

162-1 Aerobic Soil Metabolism - Unacceptable 

EPA’s Responses:

According to the document provided by the registrant at the SMART
meeting on January 26, 2006, the registrant would like to support
terrestrial non-food, forest, and residential outdoor uses.    In order
to meet data requirements as stated in 40CFR, Section 158.290, the
registrant is required to submit the following studies (detailed
information can be found in the previously submitted EFED Reregistration
Chapter for Chlorflurenol):

161-1 Hydrolysis

161-2 Aqueous photolysis

161-3 Soil photolysis

162-1 Aerobic soil metabolism

162-2 Anaerobic soil metabolism

162-3 Anaerobic aquatic metabolism

163-1 Adsorption/desorption

164-1 Terrestrial field dissipation

165-4 Fish bioaccumulation

201-1 Droplet Size Spectrum 

202-1 Drift Field Evaluation

B.  Registrant’s Rebuttal on the Studies Reviewed by EPA 

1. Hydrolysis Study (161-1) - MRID 43496201 

Registrant’s Rebuttal:

The Agency classified this study as supplemental. It is scientifically
valid.  The study was conducted prior to promulgation of the GLP
regulations under 40 CFR Part 160. The Agency evaluated the study using
the Subdivision N Guidelines. This study demonstrated that the
hydrolysis of the test substance is pH dependent although it was not
tested at the prescribed pHs in Subdivision N Guidelines which require
testing at pH 5, 7 and 9. Instead, the test substance was valuated at pH
3, 6 and 9.  If the study were conducted at pH 5 with 1.8 ppm test
material, the half-life would have been more than 51 days, and the
half-life would have been less than 51 days at pH 7.  In other words,
half-life value at pH 7 would still be in days (may be 40 days) but
would not have been drastically different.  In basic medium (pH 9), the
hydrolysis is very rapid. Incidentally, the test was conducted at little
above pH 6 (pH 6.1).  The present study showed that, as the pH is
increased, there is a gradual decrease in half-life value from several
weeks (at pH 3) to less than a day (at pH 9). 

In our opinion, the study met the objective. As the reviewer pointed
out, the study is scientifically valid. The study clearly showed that
the hydrolysis of the test material is pH dependant. We agree with the
reviewer that the details (duration of the study, sampling intervals,
etc.) were not provided for studies at pH 3 (at this pH the hydrolysis
is very slow which is a useful information), but complete details were
provided for studies at pH 6 and pH 9 where you will observe the effect
of pH on the test substance.  If the study was conducted according to
Subdivision N Guidelines (at pH 5, 7 and 9), we would not have known the
fact that the hydrolysis was very slow in acidic conditions (pH 3).  The
study further showed that the test material is not stable in water and
undergoes hydrolysis.  The test material is not suitable for aqueous
formulations such as soluble concentrate (SC).  We do not completely
agree with the reviewer's statement that "the material balance was
incomplete, the analytical methods were inadequate, and the tabular data
for chlorflurenol-methyl and quantitative data for its transformation
products were not reported." In our opinion, the study author used the
accepted sampling and extraction procedures, and appropriate analytical
method (HPLC, TLC and mass spectrometry) for isolation and
identification of the test substance and the transformation
(degradation) products. As the reviewer has pointed out, the extraction
efficiency was 90-99% at pH 9 and 60-80% at pH 3 and pH 6 for the
recovery and its transformation products which were isolated by HPLC,
and identified by TLC and mass spectrometry. Since the test substance is
not radiolabeled, the recovery (material balance) of more than 60% can
be in the acceptable range taking into the consideration of solubility
of the test substance and the low concentration of the transformation
products at pH 3 and 6. At pH 9, where the hydrolysis was rapid, the
isolation and identification of the recovered products were accomplished
with more than 90% recovery. 

EPA’s Responses:

The registrant has not provided any useful information to address the
deficiencies stated in the corresponding DER.  Major deficiencies are:
(1) the material balance was incomplete (Subdivision N guidelines
require that the material balance be >90% and <110% of the applied); (2)
volatiles were not collected; and (3) the fate of chlorflurenol-methyl
in the pH 7 solution is unknown.

2. Aqueous Photolysis (161-2) 

Registrant’s Rebuttal:

The registrant claimed that the Agency has not responded to the study
protocol submitted by the registrant for the aqueous photolysis study.

EPA’s Responses:

EPA does not have the submitted study protocol; however, if the
registrant is willing to resubmit the protocol, EFED will evaluate it. 

3. Leaching Study (163-1) - MRID 43496202a 

Registrant’s Rebuttal:

The Agency classified this study as supplemental. It is scientifically
valid.  The study was conducted prior to the promulgation of GLP
regulations under 40 CFR Part 160. The Agency evaluated the study using
the Subdivision N guidelines. This study deviated from the guidelines
because the study was conducted prior to the development of the
Subdivision N Guidelines.  The reviewer commented that "for unaged and
aged soil leaching studies, it could not be determined if the German
test soils were comparable to soils found in the typical use areas in
the United States". We have been attempting to get the comparison of the
German soils to the soils in the U.S. but we found it difficult to make
the soil comparison with the limited information provided in the study
report.  According to Dr. Freddy Nachtergaele (FAO), comparison of soils
is normally done by means of equivalents in each of the national soil
classification system.  The data provided in the study report and
additional information in the publications seems to be adequate for
determining the leaching potential of chlorflurenol in soils (whether
they are German or the U.S. soils). The Subdivision N Guidelines;
require four soils, such as sand (agricultural), sandy loam, slit loam,
clay or clay-loam each having a pH within the range of 4-8. We believe
that the study met the criteria of conducting the study using four soils
whose characteristics were the same as those cited in the Subdivision N
Guidelines. The only difference is that they are foreign soils. Although
we contacted the USDA and FA0 officials as well as the German soil
scientists, our efforts were not fruitful in getting the comparison
between the German and U.S soils.  We have been informed that we need
more data (soil morphology, granulometry, etc.) in order to get real
comparison.  The study however showed that: 

1) The effluents from chlorflurenol-treated samples of soils (sand
containing humus and sandy loam) did not contain the detectable amount
of the degradation product (2-chlorofluorenone); 

2) Leaching of the parent compound and the transformation products did
not occur from these soils. See Attachment that contains a copy of the
published report by: E. Eichler, W. Heupt,  J.P.E. Anderson, K.H. Domsch
and G. Jagnow. Chlorflurenol-methyl in Soil Degradation, Leaching, and
Effect on Microbiological Processes. Arch. Environm. Contam. Toxicol.,
11,185-193 (1982). 

EPA’s Responses:

The registrant has not provided any useful information to address the
deficiencies stated in the corresponding DER.  Major deficiencies are:
(1) the German test soils were not compared with soils found in typical
use areas in the United States; (2) for the aged soil column leaching
study, the test substance was aged for longer than one half-life prior
to use in the leaching portion of the study; and (3) the material
balances were incomplete (<90% of the applied).  The review of the
publication submitted by the registrant in this rebuttal package will be
addressed in Item 6 below. 

4. Adsorption-Desorption Study (163-1) - MRID 43496202b 

Registrant’s Rebuttal:

The Agency classified this study as supplemental. It is scientifically
valid.  The study was conducted prior to the promulgation of GLP
regulations under 40 CFR Part 160. The Agency evaluated the study using
the Subdivision N Guidelines. This study deviated from the guidelines
because the study was conducted prior to the development of the
Subdivision N Guidelines.  Since it was conduced before Subdivision N
Guidelines were developed, there was no guideline to cite (or reference)
for the design of the study. There are also significant deviations from
the objectives of the guidelines. 

The reviewer commented that "only one test soil was used in the study
and it could not be determined if this German soil was comparable to
soils found in the typical use areas in the United States". We have been
attempting to get the comparison of the German soils with the soils in
the U.S. but we found it difficult to make the soil comparison with the
limited information provided in the study report.  According to Dr.
Freddy Nachtergaele (FAO), comparison of soils is normally done by means
of equivalents in each of the national soil classification system. The
data provided in the study report and additional information in the
publications seems to be adequate for determining the leaching potential
of chlorflurenol in soils (whether they are German or the U.S. soils).
The Subdivision N Guidelines require four soils, such as sand
(agricultural), sandy loam, slit loam, clay or clay-loam each having a
pH within the range of 4-8. We believe that the study met the criteria
of conducting the study using four soils whose characteristics were the
same as those cited in the Subdivision N Guidelines. The only difference
is that they are foreign soils. Although we contacted the USDA and FA0
officials as well as the German soil scientists, our efforts were not
fruitful in getting the comparison between the German and U.S soils.  We
have been informed that we need more data (soil morphology,
granulometry, etc.) in order to get real comparison. 

The reviewer also commented that material balance was not determined and
an equilibrating solution of a 0.01N Ca++ solution was not used. Based
on the registrant-calculated adsorption Kd, Freundlich adsorption K,
Desorption Kd, and Freundlich K values, the reviewer calculated the
corresponding Koc values for chlorflurenol in German Sandy Loam Soil
which adsorbed 60.2-82.2% of the applied chlorflurenol. 

EPA’s Responses:

The registrant has not provided any useful information to address the
deficiencies stated in the corresponding DER.  Major deficiencies are: 

1)  Only one test soil type was used in the study.  Subdivision N
guidelines specify that four different soil types should be used.

2)  It was not established that the foreign soil used in this study was
comparable to soils that would be found at the intended use sites in the
United States.  The test soil was from Germany.

3)  Material balances were not determined.  Mass balances should have
been determined for all test concentrations/test soil groups following
adsorption and following desorption.

4)  An equilibrating solution of 0.01N Ca ion solution was not used in
the study, as specified by Subdivision N guidelines.  Instead, an
equilibrating solution of high quality water (HQW) was used.  

5.  Aerobic Soil Metabolism Study (162-1) - MRID 43595403 

Registrant’s Rebuttal:

The Agency classified this study as unacceptable.  The study was
conducted (in 1969) prior to the promulgation of GLP regulations under
40 CFR Part 160. The Agency evaluated the study using the Subdivision N
Guidelines.  This study deviated from the guidelines because the study
was conducted prior to the implementation of the Subdivision N
Guidelines.  Since it was conduced before Subdivision N Guidelines
became effective, the guideline used to design the study was not
identified. There are also significant deviations from the objectives of
the guidelines. 

The reviewer cited the following reasons for unacceptability of the
study: 

1)  A U.S. soil was not used and the foreign soil was not compared to a
U.S. soil. 

2)  The study was conducted outside where the environmental conditions
were neither controlled nor reported. 

3)  The material balance was incomplete, volatiles were not collected
and the sampling intervals were inadequate to accurately establish
half-life. 

4)  The analytical method was inadequate at identifying all potential
transformation products. 

The registrant submits the following response with regards to item #1
(Re. comparison of the German soil to U.S. soil).  We have been
attempting to get the comparison of the German soils to the soils in the
U.S. but we found it difficult to make the soil comparison with the
limited information provided in the study report.   According to Dr.
Freddy Nachtergaele (FAO), comparison of soils is normally done by means
of equivalents in each of the national soil classification system.  The
data provided in the study report and additional information in the
publications seems to be adequate for determining the leaching potential
of chlorflurenol in soils (whether they are German or the U.S. soils).
The Subdivision N Guidelines require four soils, such as sand
(agricultural), sandy loam, slit loam, clay or clay-loam each having a
pH within the range of 4-8. We believe that the study met the criteria
of conducting the study using four soils whose characteristics were the
same as those cited in the Subdivision N Guidelines. The only difference
is that they are foreign soils. Although we contacted the USDA and FA0
officials as well as the German soil scientists, our efforts were not
fruitful in getting the comparison between the German and U.S soils. We
have been informed that we need more data (soil morphology,
granulometry, etc.) in order to get real comparison.] In support of this
study, we wish to provide a published paper in which the degradation of
chlorflurenol in different types of German soils was fully investigated.
Although the characterization of soils is difficult with the limited
data was presented, nevertheless such soils are not uncommon in the U.S.
 In support of this study, we wish to provide a published paper in which
the degradation of chlorflurenol in different types of German soils was
fully investigated. 

Publication:  E. Eichler, W. Heupt, J.P.E. Anderson, K.H. Domsch and G.
Jagnow. Chlorflurenol-methyl in Soil: Degradation, Leaching, and Effect
on Microbiological Processes. Arch. Environm. Contam. Toxicol., 11,185-
193 (1982). 

EPA’s Responses:

The registrant has not provided any useful information to address the
deficiencies stated in the corresponding DER.  Major deficiencies are: 

1)  It was not established that the soil used in this study was
comparable to soils that would be found at the intended use sites in the
United States.  The soil used in this study was from Germany and the FAO
classification was not provided.   

2) The study was conducted outdoors in the summer where the
environmental conditions, soil aerobicity, microbial viability, and soil
moisture were neither controlled nor reported.  Subdivision N Guidelines
require that the study be conducted in the dark at a constant
temperature, such as 25C.  

3)  The material balance was incomplete because some transformation
products may not have been identified or quantified, non-radiolabeled
test material was used, volatiles were not collected and the application
rate was not confirmed.  Subdivision N Guidelines require that the
material balance be >90% to <110%.

The review of this publication attached to this rebuttal package will be
addressed in Item 6 below. 

6.  A publication submitted by the registrant (E. Eichler, W. Heupt,
J.P.E. Anderson, K.H. Domsch and G. Jagnow. Chlorflurenol-methyl in
Soil: Degradation, Leaching, and Effect on Microbiological Processes.
Arch. Environm. Contam. Toxicol., 11,185-193 (1982)) 

Registrant’s Rebuttal:

The registrant claimed that the degradation of chlorflurenol in
different types of German soils was fully investigated  The following
information is provided in this paper: 

1)  Chlorflurenol is rapidly degraded from the soils with less than 50%
being recovered within the first 24 hours of incubation. 

2)  More than 90% of the applied chlorflurenol can not be recovered
after one week. 

3)  The transformation (degradation) product is 2-chloroflurenone. 

4)  When 2-chloroflurenone was applied to soil (in separate
experiments), all the applied material was no longer detectable after 4
weeks. 

5)  Chlorflurenol influences anaerobic and aerobic fixation of nitrogen
but does not cause persistent inhibition of anaerobic and aerobic
nitrogen fixation in the two soils tested. 

6)  Chlorflurenol does not seem to have negative influence on the
numbers of bacterial, actinomycete or fungal propagules in soils.

Below is the abstract cited directly from the publication: 

Tests were conducted with the synthetic growth regulator
chlorflurenol-methyl to investigate its rate of degradation in soil,
leaching behavior, and possible side-effects on the soil microflora and
on soil physiological processes.  With two sandy soils (Ct = 1.0 and
2.58%) which were treated with 11.35 mg kg-1 ch1orflureno1-methyl (22.8
kg a.i. ha-1), over 90% of the compound disappeared within 4 to 8 days.
The degradation products were 2-chloro-9-hydroxyfluorene-9-carboxylic
acid and 2-chlorofluorenone, which undergo further decomposition. In
leaching tests with three sandy soils (Ct = 0.69, 1.0 and 2.58%),
chlorflurenol-methyl was not washed from the soil; however, with one
soil (0.69% C), very small residues were observed in the effluent
identified as 2-chlorofluorenone. In side-effects experiments with a
parabrown (Ct = 1.26%) and a chernozem soil (Ct = 2.3%), which were
treated with 1 and 10 mg kg-1 chlorflurenolmethyl, no persistent
inhibition of anaerobic or aerobic nitrogen fixation (C,H,-reduction)
was detected.  Ammonification, nitrification, and mineralization of
soluble starch were also not influenced. The mineralization of cellulose
in compost soil (Ct = 13.59%) was temporarily delayed; however, this
delay was later compensated for by a higher mineralization rate. The
colonization density of fungi on soil particles and the numbers of
bacteria, actinomycetes, and fungi were not negatively influenced.
Chlorflurenol-methyl does not significantly influence these
microbiological processes and populations in the soil. 

EPA’s Responses:

This publication cannot be used to fulfill the aerobic soil metabolism
and the leaching/adsorption data requirements.  Major deficiencies are
listed below:

1)  The German soils used in the soil metabolism and the column leaching
experiments were not compared to the U.S. soils. 

2)  The soil metabolism experiment was conducted in a semi-open system. 
As a result, volatiles could not be monitored. 

3)  The material balance was incomplete in the soil metabolism
experiment.  Only 32 and 48% of the applied were recovered in two soils
at the end of this 8-day experiment. 

4)  Soil moisture was adjusted to 40% of the water holding capacity in
the soil metabolism experiment.  The Subdivision N required a soil
moisture at 75% of 1/3 bar.

5)   Although two transformation products
(2-chloro-9-hydroxyfluorene-9-carboxylic acid and 2-chlorofluorenone)
were identified in the soil metabolism experiment, the backbone of the
chemical structure for these two transformation products is as same as
that for the parent compound.   This experiment failed to monitor the
potential degradates formed from the later transformation product
(2-chlorofluorenone).

6)  The column was leached with 8-inch water, instead of 20-inch water
as required in the Subdivision N. 

Ecological Effects and Risk

A.  Response to “Data Requirements under Low Volume Exemption (LVE)
and Status of the Submitted Studies in Environmental Fate and Wildlife
and Aquatic Organisms Areas.”

Registrant’s Rebuttal:

The registrant claimed that EPA had granted low volume/minor use
exemption (LVE) and only required the following studies in the
ecotoxicology area:

71-1 Avian Oral LD50 (quail/duck) 

71-2 Avian Dietary LC50 (two studies – duck and quail) 

72-1 Acute Freshwater Fish LC50 (two studies – bluegill and rainbow
trout) 

72-2 Acute Freshwater Invertebrate LC50 

The registrant submitted three avian studies….The Agency reviewed
those studies and determined that they are acceptable.  They also
submitted two sets of studies to satisfy the data in aquatic organisms
studies….The reviewer rejected these two sets of studies as
unacceptable.

EPA Response:

According to the document provided by the registrant at the SMART
meeting on January 26, 2006, the registrant would like to support
terrestrial non-food, forest, and residential outdoor uses.    In order
to meet data requirements as stated in 40CFR, Sections 158.490, 158.540,
and 158.590, the registrant is required to submit the following studies:

71-3 Avian Reproduction

72-1 Acute Freshwater Fish LC50

72-2 Acute Freshwater Invertebrate LC50

72-3 Acute Estuarine/Marine Fish and Invertebrate

72-4 Chronic Fish

123-1 Terrestrial Plant Seedling Emergence and Vegetative Vigor

123-2 Aquatic Plant Growth

141-1 Honey Bee Acute Contact Toxicity

B.  Response to “Toxicity Data on Pesticides (including Chlorflurenol)
to Honeybees”

As stated under the section entitled, “The Insecticide Container
Label” it states, “The following partial list of pesticides
represents groups of materials ranked by toxicity to honey bees and is
presented for general information only.  Toxicity ranking may vary
depending on the formulation of a pesticide….”  The report gives no
indication as to how the “highly toxic” versus the “relatively
non-toxic” categories were derived for each pesticide.  There is no
indication of any testing or background information.  EPA requires the
Honey bee Acute Contact Toxicity test according to 40CFR158.

C.  Response to “Rebuttal Reports for Aquatic Organisms Studies”

1.  Acute Toxicity Rainbow Trout (72-1c) - MRID 45137401

Deviation #1:  Not all test solutions were measured for actual
concentrations.  At 10 mg/L a precipitate was observed, indicating that
the maximum solubility had been exceeded.  Centrifugation was not
performed.

Registrant’s Rebuttal:

It is not clear to us what are those “some test levels” that were
not measured for actual concentrations….the analysis revealed that,
except for the nominal concentrations of 5.6 and 10 mg/L, other samples
that were analyzed…were in agreement (or expected to be in agreement)
with the nominal concentrations….The OECD guidelines support that the
concentration of the test substance preferably should be 80% of the
nominal concentration throughout the test.  Since the 10 mg/L nominal
concentration falls below the 80%, it was removed from the study.

EPA Response:

In the study report, it states on page 12 of 65, “Sampling for
analysis of test concentrations were performed each day at t=0 and at
t=24h, just before renewal of the test media, at day 1 and 2 from 0.56,
1.8, 5.6 and 10 mg/L and the blank control.”  This test was conducted
for 96 hours.  Samples should have also been taken at the last 24 hour
interval to show the stability of the chemical for the duration of the
test.  In guideline 850.1000 on page 8 it states, “(2) Acute static
renewal… If a static renewal test is conducted, each test chamber must
be sampled for chemical analysis at the 0–hour, at the end of the
first (or longest) cycle, and at test termination.”  In the OECD
Guidance Document on Aquatic Toxicity Testing of Difficult Substances
and Mixtures it states, “A semi-static renewal regime is recommended
where exposure can be maintained within 80-120% of the nominal values by
renewing the test media at 24 or 48 hour intervals. Analysis of the
highest and lowest test concentrations and a concentration around the
expected LC50 at the start and end of the first 24 or 48 hour renewal
period is considered the minimum requirement.”  However the exposure
did not remain above 80% of nominal concentrations for the 5.6 and 10.0
mg/L test concentrations; therefore, the stability of the test material
is in question.

On page 20 of 65, the report states, “In general the actual
concentrations of the freshly prepared test solutions at 5.6 and 10 mg/L
were below 80% relative to the nominal concentrations. Considering the
fact that at 10 mg/L the presence of undissolved test substance
particles was recorded this indicates that the maximum solubility of
CHLORFLURENOL—METHYL, TECHNICAL in the tap water used and under the
test conditions applied can be considered to be between 4 and 6 mg/L.”
 Therefore, the actual solubility limit of chlorflurenol-methyl in the
test solution is unknown and analyzed samples for the 5.6 and 10 mg/L
concentrations are in question.  Since the next lowest concentration was
not analyzed, its stability is also in question.  Even though
precipitate was not observed in any chamber except 10 mg/L, particles
too small to be seen by the naked eye may have been present.  US EPA
“requires conventional centrifugation for all test media where
undissolved test material, precipitate, flocculant, colloidal
suspension, etc., is/are observed in the test chambers or where the
solubility and hence bioavailability are in question.” (US EPA
Pesticide Reregistration Rejection Rate Analysis handbook, Appendix A,
p. 10).  Samples taken from all test concentrations should have been
centrifuged prior to analysis to determine the amount bioavailable to
the organisms.  This study remains invalid due to this reason.

Deviation #2:  The dissolved oxygen levels were much lower than 60%.

Registrant’s Rebuttal:

The oxygen concentrations in the fresh test media…decreased to below 5
mg/L because the test media were not aerated…the OECD guideline and
the approved protocol are silent with regards to aeration in a
semi-static test and no specific guidance was given regarding the
maintenance of the dissolved oxygen levels at about 60%....It is
possible that the organisms were stressed due to the lower dissolved
oxygen…even the control organisms were exposed to these conditions,
and they exhibited 100% survival.

EPA Response:

OECD Guideline for Testing of Chemicals: Fish, Acute Toxicity Test 203
states on page 2, “6.  The dissolved oxygen concentration must have
been at least 60 per cent of the air saturation value throughout the
test.”  Values in the 20% range (as in this study) are unacceptable
because the stress placed on the organisms may increase their
susceptibility to the chemical; however, since the control organisms
were subjected to the same conditions and if the study submitter accepts
that these values may be an overestimation of toxicity then the EPA will
not use this deviation to invalidate the study.  

The remaining deviations in the study did not contribute to the invalid
classification of the study.

2.  Acute Aquatic Invertebrate Toxicity (72-2a) - MRID 45137403

Deviation #1:  The study authors measured test solutions at test
initiations and after 24 hours (prior to renewal), but did not measure
solutions after renewal of the test solution or at test termination.

Registrant’s Rebuttal:

Prior to conducting this study, the product was tested for stability and
found to be stable for at least 48 hours.

EPA Response:

There is no indication in the study of a preliminary stability test.  

Measurement of the solutions should have also occurred during the second
24-hour period to show the stability of the chemical under test
conditions.  In guideline 850.1000 on page 8 it states, “(2) Acute
static renewal… If a static renewal test is conducted, each test
chamber must be sampled for chemical analysis at the 0–hour, at the
end of the first (or longest) cycle, and at test termination.”  In the
OECD Guidance Document on Aquatic Toxicity Testing of Difficult
Substances and Mixtures it states, “A semi-static renewal regime is
recommended where exposure can be maintained within 80-120% of the
nominal values by renewing the test media at 24 or 48 hour intervals.
Analysis of the highest and lowest test concentrations and a
concentration around the expected LC50 at the start and end of the first
24 or 48 hour renewal period is considered the minimum requirement.” 
However the exposure did not remain above 80% of nominal concentrations
for all test concentrations; therefore the stability of the test
material is in question.

Deviation #2:  The study author was aware of the low solubility of the
test material prior to conducting the definitive test and should have
reported details on the appearance of the test solution during the test.
 Given the low solubility of the test material, particularly at the
higher concentration, it is not clear how much test substance the
organisms were exposed to for the duration of the study.  The measured
concentrations do not accurately represent concentrations that daphnids
were exposed to during the entire study.

Registrant’s Rebuttal:

The saturated solutions, after filtrations, are analyzed to determine
the amount of the test material that is expected to be exposed to the
test organisms.  For further details, please see the study report (pages
19-20 of 56), analytical report (page 36 of 56) and also protocol (page
51 of 56).

In Table 1 (page 21 of 56) a series of 7 nominal concentrations (1.0,
1.8, 3.2, 5.6, 10, 18, 32 mg/L) was tested for mortality besides water
blank….The only test samples that were analyzed are 1.0, 5.8, and 32
mg/L nominal concentrations, besides the 10.0 mg/L (stock solution). 
This is because the analysis revealed that, except for the nominal
concentrations of 5.6 and 32 mg/L, other samples that were analyzed
(“actual concentrations”) were >80% relative to the nominal
concentration.  Those samples that were not analyzed are expected to
show that the actual concentration would be >80% of the nominal
concentrations (i.e., 80% nominal concentration = actual concentration).
 

EPA Response:

In the study report and the analytical report there is no indication of
filtration of test solution prior to analysis as indicated in the study
submitter’s response above.  

As stated on page 18 of 56, “Sampling for analysis of test
concentrations was performed in duplicate taking 5 ml from the
approximate centre of the test vessel at t=0h (just before introduction
of the daphnia) and at t=24h (just before renewal of the test media)
from 1.0, 5.6 and 32 mg/L and the blank control.”  Concentration 10
mg/L was only measured at t=0h and not at 24hours.  Mean measurements at
t=24h, were 72% for 1 mg/L, 77% for 5.6 mg/L, and 63% for 32 mg/L.  
Then later on page 20 of 56, the report contributes the low retention of
the chemical in test concentration 32 mg/L to “…the instability of
the solution at a concentration approximating the maximum solubility.”
 Since all three measured concentrations were below 80% at t=24h, the
argument that the non-analyzed samples were expected to show actual
concentrations >80% is not valid.  The stability of the test material is
in question.

The amount of the chemical that was bioavailable to the organisms is
unclear due to the low retention rate.  US EPA “requires conventional
centrifugation for all test media where undissolved test material,
precipitate, flocculant, colloidal suspension, etc., is/are observed in
the test chambers or where the solubility and hence bioavailability are
in question” (US EPA Pesticide Reregistration Rejection Rate Analysis
handbook, Appendix A, p. 10).   In addition, other submitted studies
showed low retention at multiple concentrations ≤10mg/L and even
showed a precipitate in the10 mg/L concentration (MRID 45137401,
45242603, 45242602).  Samples should have been centrifuged prior to
analysis to determine the amount bioavailable to the organisms.  This
study remains invalid.

Deviation #3:  It is unclear whether the study was conducted in
accordance with 40 CFR Part 160; a Quality Assurance Statement was not
included.

Registrant’s Rebuttal:

As shown on page 11 of 56, the subject study was conducted in accordance
with 40 CFR Part 160.  The statement on page 3 of 56 is not clear and
the study submitter regrets this ambiguous statement.  According to the
GLP compliance statement shown on page 11 of 56, the subject study
complies with the GLP regulations under 40 CFR Part 160 and also OECD
Principles of Good Laboratory Practice.  The Quality Assurance Statement
was included in the study report on page 10 of 56.

EPA Response:

The statement on page 3 of 56 was unclear but the reviewer accepts the
study submitter’s response.  This is no longer a deviation and will
not affect the acceptability of the study.

The remaining deviations in the study did not contribute to the invalid
classification of the study.

3.  Acute Aquatic Invertebrate Toxicity (72-2a) - MRID 45242603

Deviation:  Test solutions were not measured at test termination.  Given
the low solubility of this test material, the concentrations of
chlorflurenol-methyl that organisms were exposed to are unknown.  

Registrant’s Rebuttal:

The test material itself does have a low solubility, but a carrier
solvent was used to dissolve the material into test solutions. 
Observations reported in the study report indicate that no precipitate
was formed for the test material, and both material and solvent went
into solution at test set.

Test concentrations were measured on the test material at the beginning
AND end of the study.  However, only day 0 measurements were used as the
concentrations for the statistical analyses.  Because the mean results
from the HPLC analysis increase fairly consistently with increasing
nominal concentrations, and because the nominal test concentrations are
all small to begin with (≤10 mg/L), the results calculated should not
be significantly affected by the measured discrepancies.

EPA Response:

Page 11 of 42 indicates that at concentrations of 1.8 – 10 mg/L an
oily patch/sheen was observed on the surface of the water.  This may be
due to the solvent or the chemical starting to come out of solution.  In
addition, the study indicates that at 10 mg/L the test substance turned
milky white.  This is indicative of a precipitate; therefore the
bioavalability of the test material to the test organisms is unknown. 
Even though a distinct precipitate was not observed in any chamber
except 10 mg/L, particles too small to be seen by the naked eye may have
been present.  US EPA “requires conventional centrifugation for all
test media where undissolved test material, precipitate, flocculant,
colloidal suspension, etc., is/are observed in the test chambers or
where the solubility and hence bioavailability are in question.” (US
EPA Pesticide Reregistration Rejection Rate Analysis handbook, Appendix
A, p. 10).  It is also unclear what the solubility limit of the chemical
is under these testing conditions; therefore all test solutions should
have been centrifuged prior to analysis to determine the amount
bioavailable to the organisms.  

In addition there is no indication in the study report that measurements
were taken at test termination.  There is no data presented of the
analyzed test concentrations at test termination.  These should have
been included in the report if they were in fact measured.  

This study is still considered invalid.

4.  Acute Toxicity Bluegill (72-1a) - MRID 45242602

Deviation #1:  The study deviated from the guidelines in that the test
was a static test, and that a flow-through test was required.

Registrant’s Rebuttal:

EPA does not require a flow-thru test.

EPA Response:  

This is an error on the reviewer’s part.  It should read, “EPA
recommends a flow-thru test in cases where the test substance has a low
solubility.”  However, this did not contribute to the invalid
classification of the study.

Deviation#2:  Dissolved oxygen levels were extremely low by 96 hours. 
Final levels measured 0.2-0.4 mg/L (approximately <10%).

Registrant’s Rebuttal:

Normally, in a static test where the D.O. falls below 60% saturation,
the test is aerated continuously to increase D.O. levels, thus reducing
organisms stress.  However, because the test material was dissolved in
methanol, it is likely that the Study Director did not opt to aerate the
test.  It is possible that aeration in the test could have gassed-off
the solvent, which in turn could have reduced the bioavailability of the
test material to the fish.  While I agree with the reviewer that the
fish were stressed due to the lower D.O. levels, even the control
organisms were exposed to these conditions, and they exhibited 100%
survival.  Therefore, it is my opinion that the mortality of the
organisms in the test has to be attributed to the toxicity of the test
substance.  The toxicity curve exhibited by the test supports this
statement.  It is my opinion that the drop in D.O. did not have a
significant effect on the results of the study.

EPA Response:  

Values <10% (as in this study) are unacceptable because the stress
placed on the organisms may increase their susceptibility to the
chemical; however, since the control organisms were subjected to the
same conditions and if the study submitter accepts that these values may
be an overestimation of toxicity then this deviation will not contribute
to the invalid classification of the study.  

Deviation#3:  Mean measured concentrations varied greatly from nominal. 
Final measured concentrations of the fifth and sixth treatment level
varied greatly from initial measured concentrations.

Registrant’s Rebuttal:

≤10 mg/L), the results calculated should not be significantly affected
by the measured discrepancies. 

EPA Response:  

While some of the test material may have been taken up by the test
organisms, it is also possible that the test material precipitated out
of solution.  Nominal test concentrations of 0.32, 0.56, 1.0, 1.8, 3.2,
5.6, and 10 mg/L had average measured concentrations at test termination
of 0.2536, 0.3889, 0.6627, 1.2134, 0.8951, 2.8683, and 7.8687 mg/L
representing 79%, 69%, 66%, 67%, 28%, 51%, and 79%, respectively, of
nominal.  In addition, test termination concentrations of the 3.2 and
5.6 mg/L were 35 % and 65% of the initial mean measured concentrations. 
According to the US EPA Pesticide Reregistration Rejection Rate Analysis
handbook (Appendix A, p. 4), “A test material is considered to be
stable under test conditions if, under those conditions, it does not
degrade, volatilize, dissipate, precipitate, sorb to the test container
walls, or otherwise decline to concentrations less than 70% of the day-0
measured concentrations during the study period.”  The test material
is not stable and the bioavailability of the test material is therefore
in question.  

In addition, the table on page 10 of 39 indicates that at concentrations
of 1.8, 3.2, 5.6, and 10 mg/L, an oily patch/sheen was observed on the
surface of the water.  This may be due to the solvent or the chemical
starting to come out of solution.  In addition, the study indicates that
at 10 mg/L the test substance turned milky white.  This is indicative of
a precipitate; therefore the bioavalability of the chemical is unknown. 
In addition, even though a distinct precipitate was not observed in any
chamber except 10 mg/L, particles too small to be seen by the naked eye
may have been present.  US EPA “requires conventional centrifugation
for all test media where undissolved test material, precipitate,
flocculant, colloidal suspension, etc., is/are observed in the test
chambers or where the solubility and hence bioavailability are in
question.” (US EPA Pesticide Reregistration Rejection Rate Analysis
handbook, Appendix A, p. 10).  It is also unclear what the solubility
limit of the chemical is under these testing conditions; therefore all
test solutions should have been centrifuged prior to analysis to
determine the amount bioavailable to the organisms.

This study remains invalid.

5.  Acute Toxicity Rainbow Trout (72-1c) - MRID 45242601

Deviation #1:  The study deviated from the guidelines in that the test
was a static test, and that a flow-through test was required.

Registrant’s Rebuttal:

EPA does not require a flow-thru test.

EPA Response:  

This is an error on the reviewer’s part.  It should read, “EPA
recommends a flow-thru test in cases where the test substance has a low
solubility.”  However, this did not contribute to the invalid
classification of the study.

Deviation#2:  Mean measured concentrations varied greatly from nominal
and initial test concentrations varied greatly from terminal test
concentrations.

Registrant’s Rebuttal:

Test concentrations were measured on the test material at the beginning
and end of the study.  However, only the Day 0 measurements were used as
the concentrations for the statistical analyses.  The large
discrepancies in some of the measured values from the nominal
concentrations at test termination may be attributed to the fact that
the test material was being taken up by the test organisms.  Test
concentrations were relatively small, and any small amount taken up by
the organisms could have a significant effect on the overall
concentration of the material in solution.  

Because the mean results from the HPLC analysis increase fairly
consistently with increasing nominal concentration, and because the
nominal test concentrations are all small to start with (≤10 mg/L),
the results calculated should not be significantly affected by the
measured discrepancies.

EPA Response:  

While some of the test material may have been taken up by the test
organisms, it is also possible that the test material precipitated out
of solution.  Nominal concentrations were 0.32, 0.56, 1.0, 1.8, 3.2,
5.6, and 10 mg/L.  Average measured concentrations at test initiation
were 0.5378, 0.7617, 1.1107, 1.4832, 2.6785, 4.5538, and 8.1234 mg/L,
with a range of 82-168% of nominal concentrations.  By test termination,
average measured concentrations were 0.2536, 0.3889, 0.6627, 1.2134,
0.8951, 2.8683, and 7.8687 mg/L, respectively, which were 47%, 51%, 60%,
82%, 33%, 63%, and 97% of the initial mean measured concentrations. 
According to the US EPA Pesticide Reregistration Rejection Rate Analysis
handbook (Appendix A, p. 4), “A test material is considered to be
stable under test conditions if, under those conditions, it does not
degrade, volatilize, dissipate, precipitate, sorb to the test container
walls, or otherwise decline to concentrations less than 70% of the day-0
measured concentrations during the study period.”  Therefore the  test
material was not shown to be stable and the bioavailability of the test
material is therefore in question.  US EPA “requires conventional
centrifugation for all test media where undissolved test material,
precipitate, flocculant, colloidal suspension, etc., is/are observed in
the test chambers or where the solubility and hence bioavailability are
in question.” (US EPA Pesticide Reregistration Rejection Rate Analysis
handbook, Appendix A, p. 10).   Samples should have been centrifuged
prior to analysis to determine the amount bioavailable to the organisms.
 This study remains invalid.

Deviation#3:  Test concentrations dropped unacceptably low in many of
the test levels by test termination.  As a result, there was
insufficient mortality during the test to establish a reliable LC50
value.

Registrant’s Rebuttal:

The range-finder test indicated that fish were being adversely affected
at the lowest concentration tested of 1 mg/L, 50% mortality occurred at
5 mg/L, and 100% mortality occurred at 10 mg/L.  The definitive
concentrations were likely chosen to accomplish effects below 1 mg/L up
through 10 mg/L….There was significant partial mortality at the 5.6
mg/L concentration  and 100% mortality at the 10 mg/L concentration,
which is enough to calculate a reliable LC50 using Trimmed
Spearman-Karber.  This is confirmed by the fact that the 95% Confidence
Interval is only 1.1102 mg/L wide (5.2484 – 6.3586).

EPA Response:  

This deviation does affect the acceptability of the study; however, it
does not contribute to the invalid classification.

This study remains invalid due to deviations #1 and 2.

D.  Response to EFED Label Recommendations

1.  Label Statement #1:  This Pesticide is Toxic to Fish and Aquatic
Invertebrates

Registrant’s Rebuttal:

According to labeling requirements for environmental hazards under 40
CFR 156.10(h)(2)(ii)(B), if a pesticide intended for outdoor use
contains an ingredient with a fish acute LC50 of 1 ppm or less, the
statement “This Pesticide is Toxic to Fish” is required.  Since the
fish toxicity (LC50) data on chlorflurenol…is more than 1 ppm, this
statement is not required on the label.

EPA Response:  

All submitted studies for aquatic organisms are considered invalid;
therefore, the toxicity to fish and aquatic invertebrates is unknown. 

2.  Label Statement #2:  This Pesticide is Toxic to Birds and Mammals.

Registrant’s Rebuttal:

According to labeling requirements for environmental hazards under 40
CFR 156.10(h)(2)(ii)(A), if a pesticide intended for outdoor use
contains an ingredient with a mammalian acute oral LD50 of 100 or less,
the statement “This Pesticide is Toxic to Wildlife” is required. 
Since the mammalian acute oral toxicity (LD50) data on
chlorflurenol…is more than >5,000 mg a.i./kg body weight, this
statement is not required on the label.

According to labeling requirements for environmental hazards under 40
CFR 156.10(h)(2)(ii)(C), if a pesticide intended for outdoor use
contains an ingredient with an avian acute oral LD50 of 100 mg/kg or
less, the statement “This Pesticide is Toxic to Wildlife” is
required.  Since the avian acute oral toxicity (LD50) data on
chlorflurenol…is more than >10,000 mg a.i./kg body weight, this
statement is not required on the label.

EPA Response:  

It is correct that this statement should not appear on the label and
will be removed from the document.

3.  Label Statement#3:  This product is highly toxic to bees exposed to
direct treatment on blooming crops or weeds. Do not apply this product
or allow it to drift to blooming crops or weeds while bees are actively
visiting the treatment area.

Registrant’s Rebuttal:

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ee studies—The registrant is not required to develop honeybee toxicity
studies on chlorflurenol under LVE.  However, chlorflurenol is not a
toxicant based on the published report.  We request the Agency to use
the published information.

EPA Response:  

The report cited above gives general information about the toxicity to
honeybees.  However, there are no details in this report.  EFED does not
know how the determination about its toxicity was made.  The report
cannot be used.

DP Barcode D362456 Environmental Fate and Ecological Risk Assessment for
the Reregistration of Chlorflurenol.  Dated 6/30/06

http://www.epa.gov/oppfead1/endanger/consultation/ecorisk-overview.pdf