[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: opp-
[email protected]. 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:

------------------------------------------------------------------------
                                   Office location/                     
        Product Manager            telephone number          Address    
------------------------------------------------------------------------
Adam Heyward (PM 13)..........  Rm. 227, CM #2, 703-    1921 Jefferson  
                                 305-5418, e-mail:       Davis Hwy,     
                                 heyward.adam@epamail.   Arlington, VA  
                                 epa.gov.                               
Beth Edwards (PM 13)..........  Rm. 206, CM #2, 703-    Do.             
                                 305-5400, e-mail:                      
                                 edwards.beth@epamail.
epa.gov.                               
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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:
    [email protected]


    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