[Federal Register Volume 62, Number 204 (Wednesday, October 22, 1997)]
[Rules and Regulations]
[Pages 54778-54784]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-27843]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 180
[OPP-300548; FRL-5742-5]
RIN 2070-AB78
Pyrithiobac Sodium Salt; Time-Limited Pesticide Tolerance
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: This regulation extends the time-limited tolerance for
residues of the herbicide pyrithiobac sodium salt (sodium 2-chloro-6-
[(4,6-dimethoxypyrimidin-2-yl)thio]benzoate) in or on cottonseed at
0.02 parts per million (ppm). E.I. du Pont de Nemours & Co., Inc.,
requested this tolerance under the Federal Food, Drug and Cosmetic Act
(FFDCA), as amended by the Food Quality Protection Act of 1966 (Pub. L.
104-170). The tolerance will expire on September 30, 1999.
DATES: This regulation is effective October 22, 1997. Objections and
requests for hearings must be received by EPA on or before December 22,
1997.
ADDRESSES: Written objections and hearing requests, identified by the
docket control number, [OPP-300548], must be submitted to: Hearing
Clerk (1900), Environmental Protection Agency, Rm. M3708, 401 M St.,
SW., Washington, DC 20460. Fees accompanying objections and hearing
requests shall be labeled ``Tolerance Petition Fees'' and forwarded to:
EPA Headquarters Accounting Operations Branch, OPP (Tolerance Fees),
P.O. Box 360277M, Pittsburgh, PA 15251. A copy of any objections and
hearing requests filed with the Hearing Clerk identified by the docket
control number, [OPP-300548], must also be submitted to: Public
Information and Records Integrity Branch, Information Resources and
Services Division (7506C), Office of Pesticide Programs, Environmental
Protection Agency, 401 M St., SW., Washington, DC 20460. In person,
bring a copy of objections and hearing requests to Rm. 1132, CM #2,
1921 Jefferson Davis Hwy., Arlington, VA.
A copy of objections and hearing requests filed with the Hearing
Clerk may also be submitted electronically by sending electronic mail
(e-mail) to: opp-docket@epamail.epa.gov. Copies of objections and
hearing requests must be submitted as an ASCII file avoiding the use of
special characters and any form of encryption. Copies of objections and
hearing requests will also be accepted on disks in WordPerfect 5.1 file
format or ASCII file format. All copies of objections and hearing
requests in electronic form must be identified by the docket control
number [OPP-300548]. No Confidential Business Information (CBI) should
be submitted through e-mail. Electronic copies of objections and
hearing requests on this rule may be filed online at many Federal
Depository Libraries.
FOR FURTHER INFORMATION CONTACT: By mail: James A. Tompkins,
Registration Division 7505C, Office of Pesticide Programs,
Environmental Protection Agency, 401 M St., SW., Washington, DC 20460.
Office location, telephone number, and e-mail address: Crystal Mall #2,
1921 Jefferson Davis Hwy., Arlington, VA, (703) 305-5697, e-mail:
tompkins.james@epamail.epa.gov.
SUPPLEMENTARY INFORMATION: In the Federal Register of July 11, 1997 (62
FR 37241)(FRL-5728-7), EPA, issued a notice pursuant to section 408 of
the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a(e)
announcing the filing of a pesticide petition (PP 4F4391) for tolerance
by E.I. du Pont de Nemours & Co., Inc., Barley Mill Plaza, P.O. Box
80038, Wilmington, DE 19880-0038. This notice included a summary of the
petition prepared by du Pont. There were two comments received in
response to the notice of filing from cotton growers urging the
extension of the time limited tolerance.
The petition requested that 40 CFR 180.487 be amended by extending
the time-limited tolerance for residues of the herbicide pyrithiobac
sodium salt (sodium 2-chloro-6-[(4,6-dimethoxypyrimidin-2-
yl)thio]benzoate) in or on cottonseed at 0.02 ppm. This tolerance will
expire on September 30, 1999.
In the Federal Register of October 25, 1995 (60 FR 54607)(FRL-4982-
8), EPA established a time limited tolerance for residues of the
herbicide pyrithiobac sodium in or on cottonseed at 0.02 ppm. The time
limited tolerance will expire on September 30, 1997.
I. Risk Assessment and Statutory Findings
New section 408(b)(2)(A)(i) of the FFDCA allows EPA to establish a
tolerance (the legal limit for a pesticide chemical residue in or on a
food) only if EPA determines that the tolerance is ``safe.'' Section
408(b)(2)(A)(ii) defines ``safe'' to mean that ``there is a reasonable
certainty that no harm will result from aggregate exposure to the
pesticide chemical residue, including all anticipated dietary exposures
and all other exposures for which there is reliable information.'' This
includes exposure through drinking water and in residential settings,
but does not include occupational exposure. Section 408(b)(2)(C)
requires EPA to give special
[[Page 54779]]
consideration to exposure of infants and children to the pesticide
chemical residue in establishing a tolerance and to ``ensure that there
is a reasonable certainty that no harm will result to infants and
children from aggregate exposure to the pesticide chemical
residue....''
EPA performs a number of analyses to determine the risks from
aggregate exposure to pesticide residues. First, EPA determines the
toxicity of pesticides based primarily on toxicological studies using
laboratory animals. These studies address many adverse health effects,
including (but not limited to) reproductive effects, developmental
toxicity, toxicity to the nervous system, and carcinogenicity. Second,
EPA examines exposure to the pesticide through the diet (e.g., food and
drinking water) and through exposures that occur as a result of
pesticide use in residential settings.
A. Toxicity
1. Threshold and non-threshold effects. For many animal studies, a
dose response relationship can be determined, which provides a dose
that causes adverse effects (threshold effects) and doses causing no
observed effects (the ``no-observed effect level'' or ``NOEL'').
Once a study has been evaluated and the observed effects have been
determined to be threshold effects, EPA generally divides the NOEL from
the study with the lowest NOEL by an uncertainty factor (usually 100 or
more) to determine the Reference Dose (RfD). The RfD is a level at or
below which daily aggregate exposure over a lifetime will not pose
appreciable risks to human health. An uncertainty factor (sometimes
called a ``safety factor'') of 100 is commonly used since it is assumed
that people may be up to 10 times more sensitive to pesticides than the
test animals, and that one person or subgroup of the population (such
as infants and children) could be up to 10 times more sensitive to a
pesticide than another. In addition, EPA assesses the potential risks
to infants and children based on the weight of the evidence of the
toxicology studies and determines whether an additional uncertainty
factor is warranted. Thus, an aggregate daily exposure to a pesticide
residue at or below the RfD (expressed as 100 percent or less of the
RfD) is generally considered acceptable by EPA. EPA generally uses the
RfD to evaluate the chronic risks posed by pesticide exposure. For
shorter term risks, EPA calculates a margin of exposure (MOE) by
dividing the estimated human exposure into the NOEL from the
appropriate animal study. Commonly, EPA finds MOEs lower than 100 to be
unacceptable. This 100-fold MOE is based on the same rationale as the
100-fold uncertainty factor.
Lifetime feeding studies in two species of laboratory animals are
conducted to screen pesticides for cancer effects. When evidence of
increased cancer is noted in these studies, the Agency conducts a
weight of the evidence review of all relevant toxicological data
including short-term and mutagenicity studies and structure activity
relationship. Once a pesticide has been classified as a potential human
carcinogen, different types of risk assessments (e.g., linear low dose
extrapolations or MOE calculation based on the appropriate NOEL) will
be carried out based on the nature of the carcinogenic response and the
Agency's knowledge of its mode of action.
2. Differences in toxic effect due to exposure duration. The
toxicological effects of a pesticide can vary with different exposure
durations. EPA considers the entire toxicity data base, and based on
the effects seen for different durations and routes of exposure,
determines which risk assessments should be done to assure that the
public is adequately protected from any pesticide exposure scenario.
Both short and long durations of exposure are always considered.
Typically, risk assessments include ``acute'', ``short-term'',
``intermediate term'', and ``chronic'' risks. These assessments are
defined by the Agency as follows.
Acute risk, by the Agency's definition, results from 1-day
consumption of food and water, and reflects toxicity which could be
expressed following a single oral exposure to the pesticide residues.
High end exposure to food and water residues are typically assumed.
Short-term risk results from exposure to the pesticide for a period
of 1-7 days, and therefore overlaps with the acute risk assessment.
Historically, this risk assessment was intended to address primarily
dermal and inhalation exposure which could result, for example, from
residential pesticide applications. However, since enaction of FQPA,
this assessment has been expanded to include both dietary and non-
dietary sources of exposure, and will typically consider exposure from
food, water, and residential uses when reliable data are available. In
this assessment, risks from average food and water exposure, and high-
end residential exposure, are aggregated. High-end exposures from all
three sources are not typically added because of the very low
probability of this occurring in most cases, and because the other
conservative assumptions built into the assessment assure adequate
protection of public health. However, for cases in which high-end
exposure can reasonably be expected from multiple sources (e.g.
frequent and widespread homeowner use in a specific geographical area),
multiple high-end risks will be aggregated and presented as part of the
comprehensive risk assessment/characterization. Since the toxicological
endpoint considered in this assessment reflects exposure over a period
of at least 7 days, an additional degree of conservatism is built into
the assessment; i.e., the risk assessment nominally covers 1-7 days
exposure, and the toxicological endpoint/NOEL is selected to be
adequate for at least 7 days of exposure. (Toxicity results at lower
levels when the dosing duration is increased.)
Intermediate-term risk results from exposure for 7 days to several
months. This assessment is handled in a manner similar to the short-
term risk assessment.
Chronic risk assessment describes risk which could result from
several months to a lifetime of exposure. For this assessment, risks
are aggregated considering average exposure from all sources for
representative population subgroups including infants and children.
B. Aggregate Exposure
In examining aggregate exposure, FFDCA section 408 requires that
EPA take into account available and reliable information concerning
exposure from the pesticide residue in the food in question, residues
in other foods for which there are tolerances, residues in groundwater
or surface water that is consumed as drinking water, and other non-
occupational exposures through pesticide use in gardens, lawns, or
buildings (residential and other indoor uses). Dietary exposure to
residues of a pesticide in a food commodity are estimated by
multiplying the average daily consumption of the food forms of that
commodity by the tolerance level or the anticipated pesticide residue
level. The Theoretical Maximum Residue Contribution (TMRC) is an
estimate of the level of residues consumed daily if each food item
contained pesticide residues equal to the tolerance. In evaluating food
exposures, EPA takes into account varying consumption patterns of major
identifiable subgroups of consumers, including infants and children.
The TMRC is a ``worst case'' estimate since it is based on the
assumptions that food contains pesticide residues at the tolerance
level
[[Page 54780]]
and that 100% of the crop is treated by pesticides that have
established tolerances. If the TMRC exceeds the RfD or poses a lifetime
cancer risk that is greater than approximately one in a million, EPA
attempts to derive a more accurate exposure estimate for the pesticide
by evaluating additional types of information (anticipated residue data
and/or percent of crop treated data) which show, generally, that
pesticide residues in most foods when they are eaten are well below
established tolerances.
Percent of crop treated estimates are derived from Federal and
private market survey data. Typically, a range of estimates are
supplied and the upper end of this range is assumed for the exposure
assessment. By using this upper end estimate of percent of crop
treated, the Agency is reasonably certain that exposure is not
understated for any significant subpopulation group. Further, regional
consumption information is taken into account through EPA's computer-
based model for evaluating the exposure of significant subpopulations
including several regional groups, to pesticide residues. For this
pesticide, the most highly exposed population subgroup (children 1 to
6) was not regionally based.
II. Aggregate Risk Assessment and Determination of Safety
Consistent with section 408(b)(2)(D), EPA has reviewed the
available scientific data and other relevant information in support of
this action, EPA has sufficient data to assess the hazards of
pyrithiobac sodium and to make a determination on aggregate exposure,
consistent with section 408(b)(2), for a time-limited tolerance for
residues of pyrithiobac sodium on cottonseed at 0.02 ppm. EPA's
assessment of the dietary exposures and risks associated with
establishing the tolerance follows.
A. Toxicological Profile
EPA has evaluated the available toxicity data and considered its
validity, completeness, and reliability as well as the relationship of
the results of the studies to human risk. EPA has also considered
available information concerning the variability of the sensitivities
of major identifiable subgroups of consumers, including infants and
children. The nature of the toxic effects caused by pyrithiobac sodium
salt are discussed below.
1. A rat acute oral study with a LD50 of 3,300
milligrams (mg)/kilogram (kg) for males and a LD50 3,200 mg/
kg for females.
2. A 90-day rat feeding study with a No Observed Effect Level
(NOEL) of 50 ppm (3.25 mg/kg/day for males and 4.14 mg/kg/day for
females) and a Lowest Observed Effect Level (LOEL) of 500 ppm (31.8 mg/
kg/day for males and 40.5 mg/kg/day for females), based on decrease
body weight gains and increased rate of hepatic B-oxidation in males.
3. A 90-day mouse feeding study with a NOEL of 500 ppm (83.1 mg/kg/
day for males and 112 mg/kg/day for females) and a LOEL of 1,500 ppm
(263 mg/kg/day for males and 384 mg/kg/day for females) based on
increased liver weight and an increased incidence of hepatocellular
hypertrophy in males and decreased neutrophil count in females.
4. A 3-month dog feeding study with a NOEL of 5,000 ppm (165 mg/kg/
day) and a LOEL of 20,000 ppm (626 mg/kg/day), based on decrease red
blood cell count, hemoglobin, and hematocrit in females and increased
liver weight in both sexes.
5. A 21-day rat dermal study with a Dermal Irritation NOEL of 50
mg/kg/day and a dermal irritation LOEL of 500 mg/kg/day based on
increased incidence of erythema and edema, and with a systemic dermal
NOEL of 500 mg/kg/day and a Systemic Dermal LOEL of 1,200 mg/kg/day
based on body weight gain inhibition.
6. A 90-day rat neurotoxicity screening battery with a systemic
NOEL of 7,000 ppm (466 mg/kg/day for males and 588 mg/kg/day for
females) and a systemic LOEL of 20,000 ppm (1376 mg/kg/day for males
and 1,609 mg/kg/day for females), based on decreased hind grip strength
and increased foot spay in males, and a neurotoxicity NOEL of 20,000
ppm [Highest Dose Tested (HDT)].
7. A 78-week dietary carcinogenicity study in mice with a NOEL of
1,500 ppm 217 mg/kg/day (males) and 319 mg/kg/day (females) and a LOEL
of 5,000 ppm 745 mg/kg/day (males) and 1,101 mg/kg/day (females) based
on decreased body weight/gain in both sexes, treatment related increase
in the incidence of foci/focus of hepatocellular alternation in males,
and increased incidence of glomerulonephropathy murine in both sexes,
and an increased incidence of infarct in the kidney and keratopathy of
the eyes. There was evidence of carcinogenicity based on significant
differences in the pair-wise comparisons of hepatocellular adenomas and
combined adenoma/carcinoma in the 150 and 1,500 dose groups (but not at
the high dose of 5,000 ppm) with the controls. The carcinogenic effects
observed are discussed below.
8. A 24-month rat chronic feeding/carcinogenicity study with a
systemic NOEL of 1,500 ppm (58.7 mg/kg/day for males and 278 mg/kg/day
for females) and a systemic LOEL of 5,000 ppm (200 mg/kg/day for males
and 918 mg/kg/day for females) based on decreases in body weight, body
weight gains and food efficiency in females, increased incidence of eye
lesions in males and females, mild changes in hematology and urinalysis
in both sexes, clinical signs suggestive of urinary tract dysfunction
in males and females, increased incidence of focal cystic degeneration
in the liver in males, increased rate of hepatic peroxisomal B-
oxidation in males and an increased incidence of inflammatory and
degenerative lesions in the kidney in females. There was evidence of
carcinogenicity based on a significant dose-related increasing trend in
kidney tubular combined adenoma/carcinoma in male rats and a
significant dose related increasing trend in kidney tubular bilateral
and/or unilateral adenomas in females. The carcinogenic effects
observed are discussed further below.
9. A 1-year dog chronic feeding study with a NOEL of 5,000 ppm (143
mg/kg/day for males and 166 mg/kg/day for females) and a LOEL of 20,000
ppm (580 mg/kg/day for males and 647 mg/kg/day for females) based on
decreases in body weight gain and increased liver weight.
10. A two generation reproduction study in rats with a maternal
NOEL of 1,500 ppm (103 mg/kg/day) and a maternal LOEL of 7,500 ppm (508
mg/kg/day ppm), based on decreased body weight/gain and food efficacy.
The Reproductive and Offspring NOEL is 7,500 ppm (508 mg/kg/day) and
the reproductive and offspring LOEL is 20,000 ppm (1,551 mg/kg/day),
based on decreased pup body weight.
11. A developmental toxicity study in rabbits with a maternal and
developmental NOEL of 300 mg/kg and a Maternal LOEL of 1,000 mg/kg
based on deaths, decreased body weight gain and feed consumption,
increased incidence of clinical signs, and an increase in abortions and
a developmental LOEL of 1,000 mg/kg, based on decreased fetal body
weight gain.
12. A developmental toxicity study in rats with a maternal NOEL 200
mg/kg and a maternal LOEL of 600 mg/kg due to increased incidence of
peritoneal staining. The developmental NOEL is 600 mg/kg and the
developmental LOEL is 1,800 mg/kg based on the increased incidence of
skeletal variations.
[[Page 54781]]
13. No evidence of gene mutation was observed in a test for
induction of forward mutations at the HGPRT locus in Chinese hamster
ovary cells. No evidence was observed for inducing reverse gene
mutation in two independent assays with Salmonella typhimurium with and
without mammalian metabolic activation. Pyrithiobac sodium was negative
for the induction of micronuclei in the bone marrow cells of mice, and
negative for induction of unscheduled DNA synthesis in rat primary
hepatocytes. Pyrithiobac sodium was positive for inducing chromosome
aberrations assay in human lymphocytes.
14. A rat metabolism study showed that radio labeled pyrithiobac
sodium is excreted in urine and feces with > 90% being eliminated
within 48 hours. A sex difference was observed in the excretion and
biotransformation. Females excreted a greater amount of the radiolabel
in the urine than males following all doing regimens, with a
corresponding lower amount being eliminated in the feces compared to
the males.
B. Toxicological Endpoints
1. Acute toxicity. EPA has concluded that no endpoint exists to
suggest any evidence of significant toxicity from 1-day or single-event
exposure.
2. Short - and intermediate - term toxicity. EPA has concluded
that available evidence does not indicate any evidence of significant
toxicity from short and intermediate term exposure.
3. Chronic toxicity. EPA has established the RfD for pyrithiobac
sodium at 0.587 milligrams/kilogram/day (mg/kg/day). This RfD is based
on the systemic NOEL of 58.7 mg/kg/day for males in the rat chronic
feeding study with a 100-fold safety factor to account for interspecies
extrapolation and intraspecies variability.
4. Carcinogenicity. The Health Effects Division Carcinogenicity
Peer Review Committee has concluded that the available data provide
limited evidence of the carcinogenicity of pyrithiobac sodium in mice
and rats and has classified pyrithiobac sodium as a Group C (possible
human carcinogen with limited evidence of carcinogenicity in animals)
in accordance with Agency guidelines, published in the Federal Register
in 1986 (51 FR 33992, September 24, 1986) and recommended that for the
purpose of risk characterization, a low dose extrapolation model should
be applied to the experimental animal tumor data for quantification for
human risk (Q1*). This decision was based on liver adenomas,
carcinomas and combined adenoma/carcinomas in the male mouse and rare
kidney tubular adenomas, carcinomas and combined adenoma/carcinomas in
male rats. The unit risk, Q1* (mg/kg/day)-1, of
pyrithiobac sodium is 1.05 x 10-3 (mg/kg/day)-1
in human equivalents based on male kidney tumors.
B. Exposures and Risks
1. From food and feed uses. Time limited tolerances have been
established (40 CFR 180.487) for the residues of pyrithiobac sodium in
or on the raw agricultural commodity cottonseed at 0.02 ppm until
September 30, 1997. Processing studies for cotton have shown that
pyrithiobac sodium does not concentrate in cottonseed processed
commodities. Risk assessments were conducted by EPA to assess dietary
exposures and risks from herbicide pyrithiobac sodium salt (sodium 2-
chloro-6-[(4,6-dimethoxypyrimidin-2-yl)thio]benzoate) as follows:
Based on the assumption that 100% of the crop is treated with
pyrithiobac sodium, the upper bound limit of the dietary carcinogenic
risk is calculated in the range of one incidence in a billion (1.0 x
10-9).
Using the NOEL of 58.7 mg/kg/day from the most sensitive species in
the rat chronic feeding study with a 100-fold safety factor, the
Reference Dose (RfD) for systemic effects is 0.58 mg/kg/day. The
theoretical maximum residue contribution (TMRC) from the established
and proposed tolerances is 0.000001 mg/kg/day and utilizes less than 1
percent of the RfD for the overall U.S. population. For exposure of the
most highly exposed subgroup in the population, children 1 through 6
years old, the TMRC is 0.000001 mg/kg/day which is still less than 1
percent of the RfD.
2. From drinking water. Pyrithiobac sodium concentration in surface
water has been estimated by using the Generic Expected Environmental
Concentrations (GENEEC) model. The worst case exposure estimate for
surface water is 7.76 parts per billion (ppb) and for ground water is
0.778 ppb. Based on the estimated exposures to pyrithiobac sodium from
drinking water, the percentage of the RfD utilized for children (1
through 6 years old) would be 0.1% of the RfD. The exposure for the
general U.S. population would be less than 0.1% of the RfD.
The worst case estimate for cancer risk from the estimated residues
of pyrithiobac sodium in drinking water is 2.3 x 10-7 .
3. From non-dietary exposure. There are no non-food uses of
pyrithiobac sodium currently registered under the FIFRA, as amended. No
non-dietary exposures are expected for the general population.
4. Cumulative exposure to substances with common mechanism of
toxicity. Section 408(b)(2)(D)(v) requires that, when considering
whether to establish, modify, or revoke a tolerance, the Agency
consider ``available information'' concerning the cumulative effects of
a particular pesticide's residues and ``other substances that have a
common mechanism of toxicity.'' The Agency believes that ``available
information'' in this context might include not only toxicity,
chemistry, and exposure data, but also scientific policies and
methodologies for understanding common mechanisms of toxicity and
conducting cumulative risk assessments. For most pesticides, although
the Agency has some information in its files that may turn out to be
helpful in eventually determining whether a pesticide shares a common
mechanism of toxicity with any other substances, EPA does not at this
time have the methodologies to resolve the complex scientific issues
concerning common mechanism of toxicity in a meaningful way. EPA has
begun a pilot process to study this issue further through the
examination of particular classes of pesticides. The Agency hopes that
the results of this pilot process will increase the Agency's scientific
understanding of this question such that EPA will be able to develop
and apply scientific principles for better determining which chemicals
have a common mechanism of toxicity and evaluating the cumulative
effects of such chemicals. The Agency anticipates, however, that even
as its understanding of the science of common mechanisms increases,
decisions on specific classes of chemicals will be heavily dependent on
chemical specific data, much of which may not be presently available.
Although at present the Agency does not know how to apply the
information in its files concerning common mechanism issues to most
risk assessments, there are pesticides as to which the common mechanism
issues can be resolved. These pesticides include pesticides that are
toxicologically dissimilar to existing chemical substances (in which
case the Agency can conclude that it is unlikely that a pesticide
shares a common mechanism of activity with other substances) and
pesticides that produce a common toxic metabolite (in which case common
mechanism of activity will be assumed).
EPA does not have, at this time, available data to determine
whether pyrithiobac sodium salt has a common
[[Page 54782]]
mechanism of toxicity with other substances or how to include this
pesticide in a cumulative risk assessment. Unlike other pesticides for
which EPA has followed a cumulative risk approach based on a common
mechanism of toxicity, pyrithiobac sodium does not appear to produce a
toxic metabolite produced by other substances. For the purposes of this
tolerance action, therefore, EPA has not assumed that pyrithiobac
sodium has a common mechanism of toxicity with other substances.
C. Aggregate Risks and Determination of Safety for U.S. Population
1. Acute, short-term, and intermediate term risk. EPA has concluded
that no endpoint exists to suggest any evidence of significant toxicity
from acute, short-term or intermediate-term exposures from the use of
pyrithiobac sodium on cotton.
2. Chronic risk. Using the exposure assumptions described above,
EPA has concluded that aggregate exposure to pyrithiobac sodium from
food and drinking water will utilize less than 0.1% of the RfD for the
U.S. population. For the major identifiable subgroup with the highest
aggregate exposure, children (1 through 6 years old), the aggregate
exposure to pyrithiobac sodium from food and drinking water will
utilize less than 0.2% of the RfD. 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 pose appreciable risks to human health.
D. Aggregate Cancer Risk for U.S. Population
Based on the upper bound potency factor (Q1*) of 1.05
x 10-3 (mg/kg/day)-1, the aggregate upper bound
lifetime cancer risk from the use of pyrithiobac sodium on cotton from
worst case estimates of residues in food and drinking water is 2.3 x
10-7.
E. Aggregate Risks and Determination of Safety for Infants and Children
1. Safety factor for infants and children--a. In general. In
assessing the potential for additional sensitivity of infants and
children to residues of pyrithiobac sodium, EPA considered data from
developmental toxicity studies in the rat and rabbit and a two-
generation reproduction study in the rat. The developmental toxicity
studies are designed to evaluate adverse effects on the developing
organism resulting from pesticide exposure during prenatal development
to one or both parents. Reproduction studies provide information
relating to effects from exposure to the pesticide on the reproductive
capability of mating animals and data on systemic toxicity.
FFDCA section 408 provides that EPA shall apply an additional
tenfold margin of safety for infants and children in the case of
threshold effects to account for pre- and post-natal toxicity and the
completeness of the database unless EPA determines that a different
margin of safety will be safe for infants and children. Margins of
safety are incorporated into EPA risk assessments either directly
through use of a MOE analysis or through using uncertainty (safety)
factors in calculating a dose level that poses no appreciable risk to
humans. EPA believes that reliable data support using the standard MOE
and uncertainty factor (usually 100 for combined inter- and intra-
species variability)) and not the additional tenfold MOE/uncertainty
factor when EPA has a complete data base under existing guidelines and
when the severity of the effect in infants or children or the potency
or unusual toxic properties of a compound do not raise concerns
regarding the adequacy of the standard MOE/safety factor.
b. Developmental and Reproductive toxicity studies. The pre- and
post-natal toxicology data base for pyrithiobac sodium is complete with
respect to current toxicological data requirements. The results of
these studies indicate that infants and children are not more sensitive
to exposure, based on the results of the oral rat and rabbit
developmental toxicity studies and the two-generation reproductive
toxicity study in rats. Therefore, EPA concludes an additional tenfold
safety factor is not necessary.
2. Chronic risk. Using the conservative exposure assumptions
described above, EPA has concluded that aggregate exposure to
pyrithiobac sodium from food and drinking water will utilize less than
0.2% of the RfD for infants and children. 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 pose appreciable risks to human health. EPA concludes
that there is a reasonable certainty that no harm will result to
infants and children from aggregate exposure to pyrithiobac sodium
residues.
III. Other Considerations
A. Metabolism In Plants and Animals
The metabolism of pyrithiobac sodium in plants and animals is
adequately understood for purposes of this tolerance.
B. Analytical Enforcement Methodology
An adequate analytical method, High Pressure Liquid Chromatography
- Ultra Violet (HPLC-UV) with column switching, is available for
enforcement purposes. Because of the long lead time from establishing
these tolerances to publication of the enforcement methodology in the
Pesticide Analytical Manual, Vol. II, the analytical methodology is
being made available in the interim to anyone interested in pesticide
enforcement when requested from: Calvin Furlow, Public Information and
Records Integrity Branch, Information Resources and Records Service
(7506C), Office of Pesticide Programs, Environmental Protection Agency,
401 M St., SW., Washington, DC 20460. Office location and telephone
number: Room 1130A, CM#2, 1921 Jefferson Davis Highway, Arlington, VA
22202, (703-305-5937).
C. Magnitude of Residues
The nature of the residue in plants is adequately understood for
the purposes of this time-limited tolerance.
D. International Residue Limits
There are no Codex Alimentarius Commission (Codex) Maximum Residue
Levels (MRLs) for pyrithiobac sodium.
IV. Conclusion
The analysis for pyrithiobac sodium using tolerance level residues
for all population subgroups examined by EPA shows the use on cotton
will not cause exposure at which the Agency believes there is an
appreciable risk. Based on the information cited above, EPA has
determined that the extension of the time limited tolerance for
residues of pyrithiobac sodium in cottonseed at 0.02 ppm until
September 30, 1999 by amending 40 CFR 180.487 will be safe; therefore,
the tolerances are extended as set forth below.
V. Objections and Hearing Requests
The new FFDCA section 408(g) provides essentially the same process
for persons to ``object'' to a tolerance regulation issued by EPA under
new section 408(e) and (l)(6) as was provided in the old section 408
and in section 409. However, the period for filing objections is 60
days, rather than 30 days. EPA currently has procedural regulations
which govern the submission of objections and hearing requests. These
regulations will require some modification to reflect the new law.
However, until those modifications can be made, EPA will continue to
use
[[Page 54783]]
those procedural regulations with appropriate adjustments to reflect
the new law.
Any person may, by December 22, 1997, file written objections to
any aspect of this regulation and may also request a hearing on those
objections. Objections and hearing requests must be filed with the
Hearing Clerk, at the address given above (40 CFR 178.20). A copy of
the objections and/or hearing requests filed with the Hearing Clerk
should be submitted to the OPP docket for this rulemaking. The
objections submitted must specify the provisions of the regulation
deemed objectionable and the grounds for the objections (40 CFR
178.25). Each objection must be accompanied by the fee prescribed by 40
CFR 180.33(i). If a hearing is requested, the objections must include a
statement of the factual issues on which a hearing is requested, the
requestor's contentions on such issues, and a summary of any evidence
relied upon by the requestor (40 CFR 178.27). A request for a hearing
will be granted if the Administrator determines that the material
submitted shows the following: There is genuine and substantial issue
of fact; there is a reasonable possibility that available evidence
identified by the requestor would, if established, resolve one or more
of such issues in favor of the requestor, taking into account
uncontested claims or facts to the contrary; and resolution of the
factual issues in the manner sought by the requestor would be adequate
to justify the action requested (40 CFR 178.32). Information submitted
in connection with an objection or hearing request may be claimed
confidential by marking any part or all of that information as
Confidential Business Information (CBI). Information so marked will not
be disclosed except in accordance with procedures set forth in 40 CFR
part 2. A copy of the information 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.
VI. Public Docket
EPA has established a record for this rulemaking under docket
control number [OPP-300548] (including any comments and data submitted
electronically). 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 public
record is located in Room 1132 of the Public Information and Records
Integrity Branch, Information Resources and Services Division (7506C),
Office of Pesticide Programs, Environmental Protection Agency, Crystal
Mall #2, 1921 Jefferson Davis Highway, Arlington, VA.
Electronic comments may 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.
The official record for this rulemaking, as well as the public
version, as described above will be kept in paper form. Accordingly,
EPA will transfer any copies of objections and hearing requests
received electronically into printed, paper form as they are received
and will place the paper copies in the official rulemaking record which
will also include all comments submitted directly in writing. The
official rulemaking record is the paper record maintained at the
Virginia address in ``ADDRESSES'' at the beginning of this document.
VII. Regulatory Assessment Requirements
This final rule establishes a tolerance under FFDCA section 408(d)
in response to a petition submitted to the Agency. The Office of
Management and Budget (OMB) has exempted these types of actions from
review under Executive Order 12866, entitled Regulatory Planning and
Review (58 FR 51735, October 4, 1993). This final rule does not contain
any information collections subject to OMB approval under the Paperwork
Reduction Act (PRA), 44 U.S.C. 3501 et seq., or impose any enforceable
duty or contain any unfunded mandate as described under Title II of the
Unfunded Mandates Reform Act of 1995 (UMRA) (Pub. L. 104-4). Nor does
it require any prior consultation as specified by Executive Order
12875, entitled Enhancing the Intergovernmental Partnership (58 FR
58093, October 28, 1993), or special considerations as required by
Executive Order 12898, entitled Federal Actions to Address
Environmental Justice in Minority Populations and Low-Income
Populations (59 FR 7629, February 16, 1994), or require OMB review in
accordance with Executive Order 13045, entitled Protection of Children
from Environmental Health Risks and Safety Risks (62 FR 19885, April
23, 1997).
In addition, since these tolerances and exemptions that are
established on the basis of a petition under FFDCA section 408(d), such
as the tolerance in this final rule, do not require the issuance of a
proposed rule, the requirements of the Regulatory Flexibility Act (RFA)
(5 U.S.C. 601 et seq.) do not apply. Nevertheless, the Agency has
previously assessed whether establishing tolerances, exemptions from
tolerances, raising tolerance levels or expanding exemptions might
adversely impact small entities and concluded, as a generic matter,
that there is no adverse economic impact. The factual basis for the
Agency's generic certification for tolerance actions published on May
4, 1981 (46 FR 24950) and was provided to the Chief Counsel for
Advocacy of the Small Business Administration.
VIII. Submission to Congress and the General Accounting Office
Under 5 U.S.C. 801(a)(1)(A), as added by the Small Business
Regulatory Enforcement Fairness Act of 1996, the Agency has submitted a
report containing this rule and other required information to the U.S.
Senate, the U.S. House of Representatives, and the Comptroller General
of the General Accounting Office prior to publication of this rule in
today's Federal Register. This is not a ``major rule'' as defined by 5
U.S.C. 804(2).
List of Subjects in 40 CFR Part 180
Environmental protection, Administrative practice and procedure,
Agricultural commodities, Pesticides and pests, Reporting and
recordkeeping requirements.
Dated: October 1, 1997.
Daniel M. Barolo,
Director, Office of Pesticide Programs.
Therefore, 40 CFR Chapter I is amended as follows:
PART 180--[AMENDED]
1. The authority citation for part 180 continues to read as
follows:
Authority : 21 U.S.C. 346a and 371.
2. By revising Sec. 180.487 to read as follows:
Sec. 180.487 Pyrithiobac sodium; tolerances for residues.
(a) General. (1) Time-limited tolerances are established for
residues of the herbicide, pyrithiobac-sodium, sodium 2-chloro-6-[(4,6-
dimethoxypyrimidin-2-yl)thio]benzoate, in or on the food commodities in
the table in paragraph (a)(2). The tolerance will expire on the date
specified in the table.
(2) Residues in these commodities not in excess of the established
tolerance resulting from the use described in the following table
remaining after expiration of the time-limited tolerance
[[Page 54784]]
will not be considered to be actionable if the herbicide is applied
during the term of and in accordance with the provisions of paragraph
(a) of this section.
------------------------------------------------------------------------
Parts per Expiration/revocation
Commodity million date
------------------------------------------------------------------------
Cottonseed......................... 0.02 Sept. 30, 1999
------------------------------------------------------------------------
(b) Section 18 emergency exemptions. [Reserved]
(c) Tolerances with regional registrations. [Reserved]
(d) Indirect or inadvertent residues. [Reserved]
[FR Doc. 97-27843 Filed 10-21-97; 8:45 am]
BILLING CODE 6560-50-F
