[Federal Register Volume 62, Number 195 (Wednesday, October 8, 1997)]
[Notices]
[Pages 52558-52563]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-26536]
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ENVIRONMENTAL PROTECTION AGENCY
[PF-769; FRL 5748-6]
Notice of Filing of Pesticide Petitions
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice.
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SUMMARY: This notice announces the initial filing of pesticide
petitions proposing the establishment of regulations for residues of
certain pesticide chemicals in or on various food commodities.
DATES: Comments, identified by the docket control number PF-769, must
be received on or before November 7, 1997.
ADDRESSES: By mail submit written comments to: Public Information and
Records Integrity Branch, Information Resources and Services Division
(7506C), Office of Pesticides Programs, Environmental Protection
Agency, 401 M St., SW., Washington, DC 20460. In person bring comments
to: Rm. 1132, CM #2, 1921 Jefferson Davis Highway, Arlington, VA.
Comments and data may also be submitted electronically to: docket@epamail.epa.gov. Follow the instructions under ``SUPPLEMENTARY
INFORMATION'' of this document. No Confidential Business Information
(CBI) should be submitted through e-mail.
Information submitted as a comment concerning this document may be
claimed confidential by marking any part or all of that information as
CBI. Information so marked will not be disclosed except in accordance
with procedures set forth in 40 CFR part 2. A copy of the comment that
does not contain CBI must be submitted for inclusion in the public
record. Information not marked confidential may be disclosed publicly
by EPA without prior notice. All written comments will be available for
public inspection in Rm. 1132 at the address given above, from 8:30
a.m. to 4 p.m.,
[[Page 52559]]
Monday through Friday, excluding legal holidays.
FOR FURTHER INFORMATION CONTACT: The product manager listed in the
table below:
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Office location/
Product Manager telephone number Address
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Adam Heyward (PM 13).......... Rm. 227, CM #2, 703- 1921 Jefferson
305-5418, e-mail: Davis Hwy,
[email protected] Arlington, VA
epa.gov.
Beth Edwards (PM 13).......... Rm. 206, CM #2, 703- Do.
305-5400, e-mail:
edwards.beth@epamail..
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SUPPLEMENTARY INFORMATION: EPA has received pesticide petitions as
follows proposing the establishment and/or amendment of regulations for
residues of certain pesticide chemicals in or on various food
commodities under section 408 of the Federal Food, Drug, and Comestic
Act (FFDCA), 21 U.S.C. 346a. EPA has determined that these petitions
contain data or information regarding the elements set forth in section
408(d)(2); however, EPA has not fully evaluated the sufficiency of the
submitted data at this time or whether the data supports granting of
the petition. Additional data may be needed before EPA rules on the
petition.
The official record for this notice of filing, as well as the
public version, has been established for this notice of filing under
docket control number [PF-769] (including comments and data submitted
electronically as described below). A public version of this record,
including printed, paper versions of electronic comments, which does
not include any information claimed as CBI, is available for inspection
from 8:30 a.m. to 4 p.m., Monday through Friday, excluding legal
holidays. The official record is located at the address in
``ADDRESSES'' at the beginning of this document.
Electronic comments can be sent directly to EPA at:
opp-docket@epamail.epa.gov
Electronic comments must be submitted as an ASCII file avoiding the
use of special characters and any form of encryption. Comment and data
will also be accepted on disks in Wordperfect 5.1 file format or ASCII
file format. All comments and data in electronic form must be
identified by the docket number PF-769 and appropriate petition number.
Electronic comments on notice may be filed online at many Federal
Depository Libraries.
List of Subjects
Environmental protection, Agricultural commodities, Food additives,
Feed additives, Pesticides and pests, Reporting and recordkeeping
requirements.
Dated: September 25, 1997.
James Jones,
Acting Director, Registration Division, Office of Pesticide Programs.
Summaries of Petitions
Petitioner summaries of the pesticide petitions are printed below
as required by section 408(d)(3) of the FFDCA. The summaries of the
petitions were prepared by the petitioners and represent the views of
the petitioners. EPA is publishing the petition summaries verbatim
without editing them in any way. The petition summary announces the
availability of a description of the analytical methods available to
EPA for the detection and measurement of the pesticide chemical
residues or an explanation of why no such method is needed.
1. DowElanco
PP 7F4871
EPA has received a pesticide petition (PP 7F4871) from DowElanco,
9330 Zionsville Road, Indianapolis, IN 46268-1054, proposing pursuant
to section 408(d) of the Federal Food, Drug and Cosmetic Act, 21 U.S.C.
346a(d), to amend 40 CFR part 180 by establishing a tolerance for
residues of spinosad in or on the raw agricultural commoditIies
almonds, nutmeat at 0.02 ppm; almonds, hulls at 2 ppm; citrus, whole
fruit at 0.3 ppm; citrus, oil at 3 ppm; citrus, dried pulp at 0.5 ppm;
and leafy vegetables at 8 ppm. Because of the amount of spinosad
residue found in almonds, hulls and citrus, dried pulp as well as wet
apple pomace (pending tolerance under PP 6F4761) and the amount of
almond hulls, citrus dried pulp, and apple pomace potentially included
in livestock rations, a livestock, fat residue tolerance of 0.7 ppm is
also being proposed. The following meat and milk tolerances for
residues of spinosad are presently pending under PP 6F4761: meat at
0.04 ppm, kidney and liver at 0.2 ppm, fat at 0.4 ppm, milk at 0.04
ppm, and milk fat at 0.5 ppm. An adequate analytical method is
available for enforcement purposes. EPA has determined that the
petition contains data or information regarding the elements set forth
in section 408(d)(2) of the FFDCA; however, EPA has not fully evaluated
the sufficiency of the submitted data at this time or whether the data
supports granting of the petition. Additional data may be needed before
EPA rules on the petition.
A. Residue Chemistry
1. Plant metabolism. The metabolism of spinosad in plants (apples,
cabbage, cotton, tomato, and turnip) and animals (goats and poultry) is
adequately understood for the purposes of these tolerances. A
rotational crop study showed no carryover of measurable spinosad
related residues in representative test crops.
2. Magnitude of residues. Magnitude of residue studies were
conducted for almonds (6 sites), citrus (13 sites on oranges, 6 sites
on grapefruit, and 5 sites on lemons), and leafy vegetables (6 sites
each on head lettuce, leaf lettuce, spinach, and celery). Residues
found in these studies ranged from ND to 0.008 ppm on almonds, nutmeat;
0.22 to 1.45 ppm on almonds, hulls; 0.01 to 0.21 ppm on citrus, whole
fruit; and ND to 6 ppm on leafy vegetables. A processed products study
in citrus at a 5x application rate showed that residues of spinosad did
not concentrate in citrus juice; however, there was aconcentration of
spinosad residues in citrus oil (14x concentration factor) and citrus
dried pulp (2x concentration factor).
B. Toxicological Profile
1. Acute toxicity. Acute Toxicity Spinosad has low acute toxicity.
The rat oral LD50 is 3,738 mg/kg for males and >5,000 mg/kg
for females, whereas the mouse oral LD50 is >5,000 mg/kg.
The rabbit dermal LD50 is >2,000 mg/kg and the rat
inhalation LC50 is >5.18 mg/l air. In addition, spinosad is
not a skin sensitizer in guinea pigs and does not produce significant
dermal or ocular irritation in rabbits. End use formulations of
spinosad that are water based suspension concentrates have similar low
acute toxicity profiles.
2. Genotoxicty. Short term assays for genotoxicity consisting of a
bacterial reverse mutation assay (Ames test), an
[[Page 52560]]
in vitro assay for cytogenetic damage using the Chinese hamster ovary
cells, an in vitro mammalian gene mutation assay using mouse lymphoma
cells, an in vitro assay for DNA damage and repair in rat hepatocytes,
and an in vivo cytogenetic assay in the mouse bone marrow (micronucleus
test) have been conducted with spinosad. These studies show a lack of
genotoxicity.
3. Reproductive and developmental toxicity. Spinosad caused
decreased body weights in maternal rats given 200 mg/kg/day by gavage
(highest dose tested). This was not accompanied by either embryo
toxicity, fetal toxicity, or teratogenicity. The no-observed-effect
levels (NOELs) for maternal and fetal effects in rats were 50 and 200
mg/kg/day, respectively. A teratology study in rabbits showed that
spinosad caused decreased body weight gain and a few abortions in
maternal rabbits given 50 mg/kg/day (highest dose tested). Maternal
toxicity was not accompanied by either embryo toxicity, fetal toxicity,
or teratogenicity. The NOELs for maternal and fetal effects in rabbits
were 10 and 50 mg/kg/day, respectively. The NOEL found for maternal and
pup effects in a rat reproduction study was 10 mg/kg/day. Neonatal
effects at 100 mg/kg/day (highest dose tested in the rat reproduction
study) were attributed to maternal toxicity.
4. Subchronic toxicity. Spinosad was evaluated in 13-week dietary
studies and showed NOELs of 4.9 mg/kg/day in dogs, 6 mg/kg/day in mice,
and 8.6 mg/kg/day in rats. No dermal irritation or systemic toxicity
occurred in a 21-day repeated dose dermal toxicity study in rabbits
given 1,000 mg/kg/day.
5. Chronic toxicity. Based on chronic testing with spinosad in the
dog and the rat, the EPA has set a reference dose (RfD) of 0.0268 mg/
kg/day for spinosad. The RfD has incorporated a 100-fold safety factor
to the NOELs found in the chronic dog study. The NOELs shown in the dog
chronic study were 2.68 and 2.72 mg/kg/day, respectively for male and
female dogs. The NOELs shown in the rat chronic study were 2.4 and 3.0
mg/kg/day, respectively for male and female rats. Using the Guidelines
for Carcinogen Risk Assessment published September 24, 1986 (51 FR
33992), it is proposed that spinosad be classified as Group E for
carcinogenicity (no evidence of carcinogenicity) based on the results
of carcinogenicity studies in two species. There was no evidence of
carcinogenicity in an 18-month mouse feeding study and a 24-month rat
feeding study at all dosages tested. The NOELs shown in the mouse
oncogenicity study were 11.4 and 13.8 mg/kg/day, respectively for male
and female mice. The NOELs shown in the rat chronic/oncogenicity study
were 2.4 and 3.0 mg/kg/day, respectively for male and female rats. A
maximum tolerated dose was achieved at the top dosage level tested in
both of these studies based on excessive mortality. Thus, the doses
tested are adequate for identifying a cancer risk. Accordingly, a
cancer risk assessment is not needed.
6. Animal metabolism. There were no major differences in the
bioavailability, routes or rates of excretion, or metabolism of
spinosyn A and spinosyn D following oral administration in rats. Urine
and fecal excretions were almost completed in 48-hours post-dosing. In
addition, the routes and rates of excretion were not affected by
repeated administration.
7. Metabolite toxicology. The residue of concern for tolerance
setting purposes is the parent material (spinosyn A and spinosyn D).
Thus, there is no need to address metabolite toxicity.
8. Neurotoxicity. Spinosad did not cause neurotoxicity in rats in
acute, subchronic, or chronic toxicity studies.
9. Endocrine effects. There is no evidence to suggest that spinosad
has an effect on any endocrine system.
C. Aggregate Exposure
1. Dietary exposure. For purposes of assessing the potential
dietary exposure from use of spinosad on almonds, citrus, and leafy
vegetables as well as from other existing and pending uses, a
conservative estimate of aggregate exposure is determined by basing the
TMRC on the proposed tolerance levels for spinosad and assuming that
100% of the almonds, citrus, leafy vegetables, and other existing and
pending crop uses grown in the U.S. were treated with spinosad. The
TMRC is obtained by multiplying the tolerance residue levels by the
consumption data which estimates the amount of crops and related
foodstuffs consumed by various population subgroups. The use of a
tolerance level and 100% of crop treated clearly results in an
overestimate of human exposure and a safety determination for the use
of spinosad on crops cited in this summary that is based on a
conservative exposure assessment.
2. Drinking water. Another potential source of dietary exposure are
residues in drinking water. Based on the available environmental
studies conducted with spinosad wherein it's properties show little or
no mobility in soil, there is no anticipated exposure to residues of
spinosad in drinking water. In addition, there is no established
Maximum Concentration Level for residues of spinosad in drinking water.
3. Non-dietary exposure. Spinosad is currently registered for use
on cotton with several crop registrations pending all of which involve
applications of spinosad in the agriculture environment. Spinosad is
also currently registered for use on turf and ornamentals at low rates
of application (0.04 to 0.54 lb a.i. per acre). Thus, the potential for
non-dietary exposure to the general population is not expected to be
significant.
D. Cumulative Effects
The potential for cumulative effects of spinosad and other
substances that have a common mechanism of toxicity is also considered.
In terms of insect control, spinosad causes excitation of the insect
nervous system, leading to involuntary muscle contractions, prostration
with tremors, and finally paralysis. These effects are consistent with
the activation of nicotinic acetylcholine receptors by a mechanism that
is clearly novel and unique among known insecticidal compounds.
Spinosad also has effects on the GABA receptor function that may
contribute further to its insecticidal activity. Based on results found
in tests with various mammalian species, spinosad appears to have a
mechanism of toxicity like that of many amphiphilic cationic compounds.
There is no reliable information to indicate that toxic effects
produced by spinosad would be cumulative with those of any other
pesticide chemical. Thus it is appropriate to consider only the
potential risks of spinosad in an aggregate exposure assessment.
E. Safety Determination
1. U.S. population. Using the conservative exposure assumptions and
the proposed RfD described above, the aggregate exposure to spinosad
use on almonds, citrus, leafy vegetables, and other existing and
pending crop uses will utilize 20.0% of the RfD for the U.S.
population. A more realistic estimate of dietary exposure and risk
relative to a chronic toxicity endpoint is obtained if average
(anticipated) residue values from field trials are used. Inserting the
average residue values in place of tolerance residue levels produces a
more realistic, but still conservative risk assessment. Based on
average or anticipated residues in a dietary risk analysis, the use of
spinosad on almonds, citrus, leafy vegetables, and other existing and
pending crop uses will utilize 3.2% of the RfD for the U.S. population.
EPA generally has no concern for exposures below 100% of the RfD
because the RfD represents the level at or below which daily aggregate
dietary exposure over a lifetime will not
[[Page 52561]]
pose appreciable risks to human health. Thus, it is clear that there is
reasonable certainty that no harm will result from aggregate exposure
to spinosad residues on almonds, citrus, leafy vegetables, and other
existing and pending crop uses.
2. Infants and children. In assessing the potential for additional
sensitivity of infants and children to residues of spinosad, data from
developmental toxicity studies in rats and rabbits and a 2-generation
reproduction study in the rat are considered. The developmental
toxicity studies are designed to evaluate adverse effects on the
developing organism resulting from pesticide exposure during prenatal
development. Reproduction studies provide information relating to
effects from exposure to the pesticide on the reproductive capability
and potential systemic toxicity of mating animals and on various
parameters associated with the well-being of pups.
FFDCA Section 408 provides that EPA may apply an additional safety
factor for infants and children in the case of threshold effects to
account for pre- and post-natal toxicity and the completeness of the
database. Based on the current toxicological data requirements, the
database for spinosad relative to pre- and post-natal effects for
children is complete. Further, for spinosad, the NOELs in the dog
chronic feeding study which was used to calculate the RfD (0.0268 mg/
kg/day) are already lower than the NOELs from the developmental studies
in rats and rabbits by a factor of more than 10-fold.
Concerning the reproduction study in rats, the pup effects shown at
the highest dose tested were attributed to maternal toxicity.
Therefore, it is concluded that an additional uncertainty factor is not
needed and that the RfD at 0.0268 mg/kg/day is appropriate for
assessing risk to infants and children.
Using the conservative exposure assumptions previously described
(tolerance level residues), the percent (RfD) utilized by the aggregate
exposure to residues of spinosad on almonds, citrus, leafy vegetables,
and other existing and pending crop uses is 36.1% for children 1 to 6
years old, the most sensitive population subgroup. If average or
anticipated residues are used in the dietary risk analysis, the use of
spinosad on these crops will utilize 7.0% of the RfD for children 1 to
6 years old. Thus, based on the completeness and reliability of the
toxicity data and the conservative exposure assessment, it is concluded
that there is a reasonable certainty that no harm will result to
infants and children from aggregate exposure to spinosad residues on
almonds, citrus, leafy vegetables, and other existing and pending crop
uses.
F. International Tolerances
There are no Codex maximum residue levels established for residues
of spinosad on almonds, citrus, and leafy vegetables or any other food
or feed crop. (Adam Heyward)
2. Zeneca Ag Products
PP 7F4875
EPA has received a pesticide petition (PP 7F4875) from Zeneca Ag
Products, 1800 Concord Pike, P.O. Box 15458, Wilmington, DE 19850-5458.
The petition proposes pursuant to section 408(d) of the Federal Food,
Drug and Cosmetic Act, 21 U.S.C. 346a(d), to amend 40 CFR part 180 to
establish tolerances for residues of the insecticide lambda-cyhalothrin
and its epimer in or on the raw agricultural commodities avocados
(imported) at 0.2 parts per million (ppm); cereal grain crop group
(except rice and wild rice): grain, 0.2 ppm, forage (except sorghum)
6.0 ppm, hay 2.0 ppm, straw 2.0 ppm, aspirated grain dust 2.0 ppm, bran
0.8 ppm and flour 0.6 ppm; fruiting vegetable crop group (except
cucurbits) 0.2 ppm; peas and beans - edible podded crop subgroup 0.2
ppm; peas and beans - succulent shelled crop subgroup 0.01 ppm; peas
and beans - dried shelled subgroup (except soybean) 0.1 ppm; peanut hay
3.0 ppm; sorghum forage 0.3 ppm; sorghum fodder 0.5 ppm; and sugarcane
0.05 ppm. The names for lambda-cyhalothrin and its epimer are as
follows: lambda-cyhalothrin, a 1:1 mixture of (S)-alpha-cyano-3-
phenoxybenzyl-(Z)-(1R,3R)-3-(2-chloro- 3,3,3-trifluoroprop-1-enyl)-2,2-
dimethylcyclopropanecarboxylate and (R)-alpha-cyano-3-phenoxybenzyl-
(Z)-(1S,3S)-3-(2-chloro-3,3,3- trifluoroprop-1-enyl)-2,2-
dimethylcyclopropanecarboxylate. Epimer of lambda-cyhalothrin, a 1:1
mixture of (S)-alpha-cyano-3-phenoxybenzyl- (Z)(1S,3S)-3-(2-chloro-
3,3,3-trifluoroprop-1-enyl)-2,2- dimethylcyclopropanecarboxylate and
(R)-alpha-cyano-3-phenoxybenzyl- (Z)-(1R,3R)-3-(2-chloro-3,3,3-
trifluoroprop-1-enyl)-2,2- dimethylcyclopropanecarboxylate. EPA has
determined that the petition contains data or information regarding the
elements set forth in section 408(d)(2) of the FFDCA; however, EPA has
not fully evaluated the sufficiency of the submitted data at this time
or whether the data supports granting of the petition. Additional data
may be needed before EPA rules on the petition.
A. Residue Chemistry
1. Plant metabolism. The metabolism of lambda-cyhalothrin has been
studied in cotton, soybean, cabbage, and wheat plants. The studies show
that the metabolism generally follows that of other pyrethroid
insecticides. The ester linkage is cleaved to form
cyclopropanecarboxylic acids and the corresponding phenoxybenzyl
alcohol. Overall the studies show that unchanged lambda-cyhalothrin is
the principal constituent of the residue on edible portions of these
crops.
2. Analytical method. An adequate analytical method (gas liquid
chromatography with an electron capture detector) is available for
enforcement purposes.
3. Magnitude of residues. Avocados - six trials were conducted at 3
sites within Mexico. In these trials the maximum observed residue was
0.11 ppm. Peppers (nonbell) - three trials were conducted with a
maximum observed residue of 0.13 ppm. Peppers (bell) - eight trials
were conducted with a maximum observed residue of 0.16 ppm. Edible
podded peas - three trials were conducted with a maximum observed
residue of 0.14 ppm. Edible podded beans - six trials were conducted
with a maximum observed residue of 0.035 ppm. Succulent shelled peas -
six trials were conducted with a maximum observed residue of 0.01 ppm.
Succulent shelled beans - six trials were conducted with a maximum
observed residue of 0.01 ppm. Dried shelled peas - five trials were
conducted with a maximum observed residue of 0.06 ppm. Dried shelled
peas - eight trials were conducted with a maximum observed residue of
0.015 ppm. Peanut hay - eleven trials were conducted with a maximum
observed residue of 2.61 ppm. Sorghum forage and fodder - thirteen
trials were conducted with a maximum observed residue of 0.3 and 0.42
ppm, respectively, in forage and fodder. Sugarcane - nine trials were
conducted with a maximum observed residue of 0.035 ppm. A sugarcane
processing study was conducted to determine if residues concentrated in
molasses or refined sugar. No concentration of residues was observed in
either processed commodity.
B. Toxicological Profile
The following toxicity studies have been conducted to support the
request for a regulation for residues of lambda-cyhalothrin in or on
rice.
1. Acute toxicity. Acute toxicity studies with the technical grade
of the active ingredient lambda-cyhalothrin: oral LD50 in
the rat of 79 milligram/
[[Page 52562]]
kilogram (mg/kg) (males) and 56 mg/kg (females), dermal
LD50 in the rat of 632 mg/kg (males) and 696 mg/kg females,
primary eye irritation study showed mild irritation, and primary dermal
irritation study showed no irritation.
2. Genotoxicity. The following genotoxicity tests were all
negative: a gene mutation assay (Ames), a mouse micronucleus assay, an
in vitro cytogenetics assay, and a gene mutation study in mouse
lymphoma cells.
3. Reproductive and developmental toxicity--i. A three-generation
reproduction study in rats fed diets containing 0, 10, 30, and 100 ppm
with no developmental toxicity observed at 100 ppm, the highest dose
tested. The maternal no-observed-effect-level (NOEL) and lowest-
observed-effect-level (LOEL) for the study are established at 30 (1.5
mg/kg/day) and 100 ppm (5 mg/kg/day), respectively, based upon
decreased parental body weight gain. The reproductive NOEL and LOEL are
established at 30 (1.5 mg/kg/day) and 100 ppm (5 mg/kg/day),
respectively, based on decreased pup weight gain during weaning.
ii. A developmental toxicity study in rats given gavage doses of 0,
5, 10, and 15 mg/kg/day with no developmental toxicity observed under
the conditions of the study. The developmental NOEL is greater than 15
mg/kg/day, the highest dose tested. The maternal NOEL and LOEL are
established at 10 and 15 mg/kg/day, respectively, based on reduced body
weight gain.
iii. A developmental toxicity study in rabbits given gavage doses
of 0, 3, 10, and 30 mg/kg/day with no developmental toxicity observed
under the conditions of the study. The maternal NOEL and LOEL are
established at 10 and 30 mg/kg/day, respectively, based on decreased
body weight gain. The developmental NOEL is greater than 30 mg/kg/day,
the highest dose tested.
4. Subchronic toxicity--i. A 90-day feeding study in rats fed doses
of 0, 10, 50, and 250 ppm with a NOEL of 50 ppm and a LOEL of 250 ppm
based on body weight gain reduction.
ii. A 21-day study in rabbits exposed dermally to doses of 0, 10,
100, and 1,000 mg/kg/day, 6 hours/day, 5 days/week with a systemic NOEL
> 1,000 mg/kg/kg. There were no clinical signs of systemic toxicity at
any dose level tested.
5. Chronic toxicity--i. A 12-month feeding study in dogs fed dose
(by capsule) levels of 0, 0.1, 0.5, and 3.5 mg/kg/day with a NOEL of
0.1 mg/kg/day. The LOEL for this study is established at 0.5 mg/kg/day
based upon clinical signs of neurotoxicity.
ii. A 24-month chronic feeding/carcinogenicity study with rats fed
diets containing 0, 10, 50, and 250 ppm. The NOEL was established at 50
ppm and LOEL at 250 ppm based on reduced body weight gain. There were
no carcinogenic effects observed under the conditions of the study.
iii. A carcinogenicity study in mice fed dose levels of 0, 20, 100,
or 500 ppm (0, 3, 15, or 75 mg/kg/day) in the diet for 2 years. A
systemic NOEL was established at 100 ppm and systemic LOEL at 500 ppm
based on decreased body weight gain in males throughout the study at
500 ppm. The Agency has classified lambda-cyhalothrin as a Group D
carcinogen (not classifiable due to an equivocal finding in this
study). Zeneca concludes that no treatment-related carcinogenic effects
were observed under the conditions of the study.
6. Animal metabolism. Metabolism studies in rats demonstrated that
distribution patterns and excretion rates in multiple oral dose studies
are similar to single-dose studies. There is an accumulation of
unchanged compound in fat upon chronic administration with slow
elimination. Otherwise, lambda-cyhalothrin was rapidly metabolized and
excreted. The metabolism of lambda-cyhalothrin in livestock has been
studied in the goat, chicken, and cow. Unchanged lambda-cyhalothrin is
the major residue component of toxicological concern in meat and milk.
7. Metabolite toxicology. The Agency has previously determined that
the metabolites of lambda-cyhalothrin are not of toxicological concern
and need not be included in the tolerance expression. Given this
determination, Zeneca concludes that there is no need to discuss
metabolite toxicity.
8. Endocrine effects. No evidence of such effects were reported in
the toxicology studies described above. There is no evidence at this
time that lambda-cyhalothrin causes endocrine effects.
C. Aggregate Exposure
1. Dietary exposure--i. Food. For the purposes of assessing the
potential dietary exposure for all existing and pending tolerances for
lambda-cyhalothrin, Zeneca has utilized available information on
anticipated residues and percent crop treated. For all existing and
pending tolerances the anticipated residue contribution (ARC) is
estimated at 0.000212 mg/kg/body weight (bwt)/day.
ii. Drinking water. Laboratory and field data have demonstrated
that lambda-cyhalothrin and its degradates are immobile in soil and
will not leach into groundwater. Other data show that lambda-
cyhalothrin is virtually insoluble in water and extremely lipophilic.
As a result, Zeneca concludes that residues reaching surface waters
from field runoff will quickly adsorb to sediment particles and be
partitioned from the water column. Zeneca concludes that together these
data indicate that residues are not expected in drinking water.
2. Non-dietary exposure. Other potential sources of exposure are
from non-occupational sources such as structural pest control and
ornamental plant and lawn use of lambda-cyhalothrin. Zeneca has no data
upon which to estimate exposure from these uses. However, given the
extremely low vapor pressure of lambda-cyhalothrin (1.5 x
10-9 millimeters (mm) of mercury (Hg)) and the low use
rates, Zeneca concludes that inhalation and dermal exposure from these
uses will be insignificant.
D. Cumulative Effects
At this time, Zeneca cannot make a determination based on available
and reliable information that lambda-cyhalothrin and other substances
that may have a common mechanism of toxicity would have cumulative
effects. Thus, Zeneca concludes that for purposes of this tolerance it
is appropriate only to consider the potential risks of lambda-
cyhalothrin in an aggregate exposure assessment.
E. Safety Determination
The acceptable Reference Dose (RfD) based on a NOEL of 0.1 mg/kg/
bwt/day from the chronic dog study and a safety factor of 100 is 0.001
mg/kg/bwt/day. A chronic dietary exposure/risk assessment has been
performed for lambda-cyhalothrin using the above RfD. Available
information on anticipated residues and percent crop treated was
incorporated into the analysis to estimate the ARC. The ARC is
generally considered a more realistic estimate than an estimate based
on tolerance level residues.
1. U.S. population. The ARC from established tolerances and the
current and pending actions are estimated to be 0.000212 mg/kg/bwt/day
and utilize 24.9% of the RfD for the U.S. population.
2. Infants and children. The ARC for children, aged 1 to 6 years
old, and non-nursing infants (subgroups most highly exposed) utilizes
77% and 48% of the RfD, respectively. Generally speaking, the Agency
has no cause for concern if ARC for all published and proposed
tolerances is less than the RfD.
[[Page 52563]]
F. International Tolerances
There are no Codex maximum residue levels (MRL) established for
residues of lambda-cyhalothrin in or on avocados; cereal grain crop
group: grain, forage, hay, straw, aspirated grain dust, bran, flour;
fruiting vegetable crop group; peas and beans - edible podded crop
subgroup; peas and beans - succulent shelled crop subgroup; peas and or
beans - dried shelled subgroup. (Beth Edwards)
[FR Doc. 97-26536 Filed 10-7-97; 8:45 am]
BILLING CODE 6560-50-F
