
[Federal Register: September 24, 2008 (Volume 73, Number 186)]
[Rules and Regulations]               
[Page 54963-54969]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr24se08-11]                         

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[EPA-HQ-OPP-2008-0405; FRL-8368-8]

 
Pendimethalin; Pesticide Tolerances

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes tolerances for combined residues 
of the herbicide pendimethalin, [N-(1-ethylpropyl)-3,4-dimethyl-2,6-
dinitrobenzenamine], and its metabolite, 4-[(1-ethylpropyl) amino]-2-
methyl-3,5-dinitrobenzyl alcohol, in or on crayfish at 0.05 parts per 
million (ppm), and cotton gin byproducts at 3.0 ppm. BASF Corporation 
requested these tolerances under the Federal Food, Drug, and Cosmetic 
Act (FFDCA).

DATES: This regulation is effective September 24, 2008. Objections and 
requests for hearings must be received on or before November 24, 2008, 
and must be filed in accordance with the instructions provided in 40 
CFR part 178 (see also Unit I.C. of the SUPPLEMENTARY INFORMATION).

ADDRESSES: EPA has established a docket for this action under docket 
identification (ID) number EPA-HQ-OPP-2008-0405. To access the 
electronic docket, go to http://www.regulations.gov, select ``Advanced 
Search,'' then ``Docket Search.'' Insert the docket ID number where 
indicated and select the ``Submit'' button. Follow the instructions on 
the regulations.gov website to view the docket index or access 
available documents. All documents in the docket are listed in the 
docket index available in regulations.gov. Although listed in the 
index, some information is not publicly available, e.g., Confidential 
Business Information (CBI) or other information whose disclosure is 
restricted by statute. Certain other material, such as copyrighted 
material, is not placed on the Internet and will be publicly available 
only in hard copy form. Publicly available docket materials are 
available in the electronic docket at http://www.regulations.gov, or, 
if only available in hard copy, at the OPP Regulatory Public Docket in 
Rm. S-4400, One Potomac Yard (South Bldg.), 2777 S. Crystal Dr., 
Arlington, VA. The Docket Facility is open from 8:30 a.m. to 4 p.m., 
Monday through Friday, excluding legal holidays. The Docket Facility 
telephone number is (703) 305-5805.

FOR FURTHER INFORMATION CONTACT: Jim Tompkins, Registration Division 
(7505P), Office of Pesticide Programs, Environmental Protection Agency, 
1200 Pennsylvania Ave., NW., Washington, DC 20460-0001; telephone 
number: (703) 305-5697; e-mail address: tompkins.jim@epa.gov.

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this Action Apply to Me?

    You may be potentially affected by this action if you are an 
agricultural producer, food manufacturer, or pesticide manufacturer. 
Potentially affected entities may include, but are not limited to those 
engaged in the following activities:
     Crop production (NAICS code 111).
     Animal production (NAICS code 112).
     Food manufacturing (NAICS code 311).
     Pesticide manufacturing (NAICS code 32532).
    This listing is not intended to be exhaustive, but rather to 
provide a guide

[[Page 54964]]

for readers regarding entities likely to be affected by this action. 
Other types of entities not listed in this unit could also be affected. 
The North American Industrial Classification System (NAICS) codes have 
been provided to assist you and others in determining whether this 
action might apply to certain entities. If you have any questions 
regarding the applicability of this action to a particular entity, 
consult the person listed under FOR FURTHER INFORMATION CONTACT.

B. How Can I Access Electronic Copies of this Document?

    In addition to accessing an electronic copy of this Federal 
Register document through the electronic docket at http://
www.regulations.gov, you may access this Federal Register document 
electronically through the EPA Internet under the ``Federal Register'' 
listings at http://www.epa.gov/fedrgstr. You may also access a 
frequently updated electronic version of EPA's tolerance regulations at 
40 CFR part 180 through the Government Printing Office's pilot e-CFR 
site at http://www.gpoaccess.gov/ecfr.

C. Can I File an Objection or Hearing Request?

    Under section 408(g) of FFDCA, any person may file an objection to 
any aspect of this regulation and may also request a hearing on those 
objections. You must file your objection or request a hearing on this 
regulation in accordance with the instructions provided in 40 CFR part 
178. To ensure proper receipt by EPA, you must identify docket ID 
number EPA-HQ-OPP-2008-0405 in the subject line on the first page of 
your submission. All requests must be in writing, and must be mailed or 
delivered to the Hearing Clerk as required by 40 CFR part 178 on or 
before November 24, 2008.
    In addition to filing an objection or hearing request with the 
Hearing Clerk as described in 40 CFR part 178, please submit a copy of 
the filing that does not contain any CBI for inclusion in the public 
docket that is described in ADDRESSES. Information not marked 
confidential pursuant to 40 CFR part 2 may be disclosed publicly by EPA 
without prior notice. Submit this copy, identified by docket ID number 
EPA-HQ-OPP-2008-0405, by one of the following methods:
     Federal eRulemaking Portal: http://www.regulations.gov. 
Follow the on-line instructions for submitting comments.
     Mail: Office of Pesticide Programs (OPP) Regulatory Public 
Docket (7502P), Environmental Protection Agency, 1200 Pennsylvania 
Ave., NW., Washington, DC 20460-0001.
     Delivery: OPP Regulatory Public Docket (7502P), 
Environmental Protection Agency, Rm. S-4400, One Potomac Yard (South 
Bldg.), 2777 S. Crystal Dr., Arlington, VA. Deliveries are only 
accepted during the Docket's normal hours of operation (8:30 a.m. to 4 
p.m., Monday through Friday, excluding legal holidays). Special 
arrangements should be made for deliveries of boxed information. The 
Docket Facility telephone number is (703) 305-5805.

II. Petition for Tolerance

    In the Federal Register of June 13, 2008 (73 FR 33814) (FRL-8367-
3), EPA issued a notice pursuant to section 408(d)(3) of FFDCA, 21 
U.S.C. 346a(d)(3), announcing the filing of a pesticide petition (PP 
6F7098) by BASF Corporation, 26 Davis Drive, Research Triangle Park, NC 
27709. The petition requested that 40 CFR 180.361 be amended by 
establishing tolerances for combined residues of the herbicide 
pendimethalin, N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine, 
and its metabolite, 4-[(1-ethylpropyl) amino]-2-methyl-3,5-
dinitrobenzyl alcohol, in or on crayfish at 0.05 ppm, and cotton 
byproducts at 3.0 ppm. That notice referenced a summary of the petition 
prepared by BASF Corporation, the registrant, which is available to the 
public in the docket, http://www.regulations.gov. No comments were 
received on the notice of filing.

III. Aggregate Risk Assessment and Determination of Safety

    Section 408(b)(2)(A)(i) of 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) of FFDCA 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) of FFDCA requires EPA to give special 
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. . . 
.''
    Consistent with section 408(b)(2)(D) of FFDCA, and the factors 
specified in section 408(b)(2)(D) of FFDCA, 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 and to 
make a determination on aggregate exposure for the petitioned-for 
tolerances for combined residues of the herbicide pendimethalin, N-(1-
ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine, and its metabolite, 
4-[(1-ethylpropyl) amino]-2-methyl-3,5-dinitrobenzyl alcohol, in or on 
the raw agricultural commodity crayfish at 0.05 ppm, and cotton 
byproducts at 3.0 ppm. EPA's assessment of exposures and risks 
associated with establishing tolerances 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.
    Pendimethalin has low acute oral, dermal, and inhalation toxicity. 
The thyroid is a target organ for pendimethalin in chronic studies. 
Thyroid toxicity in chronic and subchronic rat and mouse studies was 
manifested as alterations in thyroid hormones (decreased Total T4, and 
T3, increased percent of free T4 and T3) increased thyroid weight, and 
microscopic thyroid lesions (including increased thyroid follicular 
cell height, follicular cell hyperplasia, as well as follicular cell 
adenomas).
    The data provided no indication of increased susceptibility 
following pre-/postnatal exposure in the two-generation reproduction 
study in rats. Pendimethalin is classified as a ``Group C'', possible 
human carcinogen, chemical based on a statistically significant 
increased trend and pair-wise comparison between the high dose group 
and controls for thyroid follicular cell adenomas in male and female 
rats. A non-quantitative cancer risk assessment approach is being 
followed since mode of action studies are available that demonstrate 
that the thyroid tumors are due to a thyroid-pituitary imbalance, and 
also since pendimethalin was shown to be non-mutagenic in mammalian 
somatic cells and germ cells. The chronic risk assessment is considered 
to be protective of any cancer effects.

[[Page 54965]]

B. Toxicological Endpoints

    For hazards that have a threshold below which there is no 
appreciable risk, a toxicological point of departure (POD) is 
identified as the basis for derivation of reference values for risk 
assessment. The POD may be defined as the highest dose at which no 
adverse effects are observed (the NOAEL) in the toxicology study 
identified as appropriate for use in risk assessment. However, if a 
NOAEL cannot be determined, the lowest dose at which adverse effects of 
concern are identified (the LOAEL) or a Benchmark Dose (BMD) approach 
is sometimes used for risk assessment. Uncertainty/safety factors (UFs) 
are used in conjunction with the POD to take into account uncertainties 
inherent in the extrapolation from laboratory animal data to humans and 
in the variations in sensitivity among members of the human population 
as well as other unknowns. Safety is assessed for acute and chronic 
dietary risks by comparing aggregate food and water exposure to the 
pesticide to the acute population adjusted dose (aPAD) and chronic 
population adjusted dose (cPAD). The aPAD and cPAD are calculated by 
dividing the POD by all applicable UFs. Aggregate short-, intermediate-
, and chronic-term risks are evaluated by comparing food, water, and 
residential exposure to the POD to ensure that the margin of exposure 
(MOE) called for by the product of all applicable UFs is not exceeded. 
This latter value is referred to as the Level of Concern (LOC).
    For non-threshold risks, the Agency assumes that any amount of 
exposure will lead to some degree of risk. Thus, the Agency estimates 
risk in terms of the probability of an occurrence of the adverse effect 
greater than that expected in a lifetime. For more information on the 
general principles EPA uses in risk characterization and a complete 
description of the risk assessment process, see http://www.epa.gov/
pesticides/factsheets/riskassess.htm.
    A summary of the toxicological endpoints for chemical name used for 
human risk assessment is shown in the table of this unit.

 Table 1.--Summary of Toxicological Doses and Endpoints for the Herbicide Pendimethalin, N-(1-ethylpropyl)-3,4-
    dimethyl-2,6-dinitrobenzenamine, and Its Metabolite, 4-[(1-ethylpropyl) amino]-2-methyl-3,5-dinitrobenzyl
                                    alcohol, for Use in Human Risk Assessment
----------------------------------------------------------------------------------------------------------------
                                                                          RfD, PAD, Level of       Study and
        Exposure Scenario         Point of Departure   Dose Used in Risk   Concern for Risk      Toxicological
                                                        Assessment, UF        Assessment            Effects
----------------------------------------------------------------------------------------------------------------
Acute Dietary                     NA                  NA                  NA                  No appropriate
(Females 13-49).................                                                               acute endpoint
(General U.S population)........                                                               identified for
                                                                                               these groups.
                                                                                               There were no
                                                                                               toxic effects
                                                                                               attributable to a
                                                                                               single dose.
----------------------------------------------------------------------------------------------------------------
Chronic Dietary                   NOAEL = 10 mg/kg/   UFH = 10X           Chronic RfD = 0.03  92-day thyroid
(All populations)...............   day                UFA = 3X..........   mg/kg/day           function study in
                                  Chronic RfD = 0.03  UFDB = 10X........  cPAD = Chronic/RfD   rats; 56-day
                                   mg/kg/day.         Total UF = 300X...  cPAD = 0.03 mg/kg/   thyroid study in
                                                                           day.                rats; 14-day
                                                                                               intra thyroid
                                                                                               metabolism study
                                                                                               in rats.
                                                                                              LOAEL = 31 mg/kg/
                                                                                               day based on
                                                                                               hormonal and
                                                                                               histopathological
                                                                                               changes in the
                                                                                               thyroid.
----------------------------------------------------------------------------------------------------------------
Incidental Oral Short-Term        NOAEL = 10 mg/kg/   UFH = 10X           Residential LOC =   92-day thyroid
(1-30 days).....................   day                UFA = 3X..........   300                 function study in
Intermediate-Term...............                      UFDB = 10X........                       rats; 56-day
(1-6 months)....................                      Total UF = 300X...                       thyroid study in
                                                                                               rats; 14-day
                                                                                               intra thyroid
                                                                                               metabolism study
                                                                                               in rats.
                                                                                              LOAEL = 31 mg/kg/
                                                                                               day based on
                                                                                               hormonal and
                                                                                               histopathological
                                                                                               changes in the
                                                                                               thyroid.
----------------------------------------------------------------------------------------------------------------
Dermal Short-Term                 NOAEL = 10 mg/kg/   UFH = 10X           Residential LOC =   92-day thyroid
(1-30 days).....................   day                UFA = 3X..........   300                 function study in
Intermediate-Term...............                      UFDB = 10X........                       rats; 56-day
(1-6 months)....................                      Total UF = 300X...                       thyroid study in
Long-Term.......................                      Dermal Absorption                        rats; 14-day
(> 6 months)....................                       = 3%.                                   intra thyroid
                                                                                               metabolism study
                                                                                               in rats.
                                                                                              LOAEL = 31 mg/kg/
                                                                                               day based on
                                                                                               hormonal and
                                                                                               histopathological
                                                                                               changes in the
                                                                                               thyroid.
----------------------------------------------------------------------------------------------------------------
Inhalation Short-Term             NOAEL = 10 mg/kg/   UFH = 10X           Residential LOC =   92-day thyroid
(1-30 days).....................   day                UFA = 3X..........   300                 function study in
Intermediate-Term...............                      UFDB = 10X........                       rats; 56-day
(1-6 months)....................                       Total UF = 300X..                       thyroid study in
Long-Term.......................                      Inhalation                               rats; 14-day
(> 6 months)....................                       toxicity is                             intra thyroid
                                                       assumed to be                           metabolism study
                                                       equivalent to                           in rats.
                                                       oral toxicity..                        LOAEL = 31 mg/kg/
                                                                                               day based on
                                                                                               hormonal and
                                                                                               histopathological
                                                                                               changes in the
                                                                                               thyroid.
----------------------------------------------------------------------------------------------------------------
Cancer                              Pendimethalin is classified as a Group C possible human   2-year chronic/
(Oral, dermal, inhalation)......   carcinogen. The chronic dietary assessment using the cPAD   carcinogenicity
                                       is considered to be protective of cancer effects.       study in rats.
----------------------------------------------------------------------------------------------------------------
Point of Departure (POD) = A data point or an estimated point that is derived from observed dose-response data
  and used to mark the beginning of extrapolation to determine risk associated with lower environmentally
  relevant human exposures. NOAEL = no observed adverse effect level. LOAEL = lowest observed adverse effect
  level. UF = uncertainty factor. UFA = extrapolation from animal to human (interspecies). UFH = potential
  variation in sensitivity among members of the human population (intraspecies). UFDB = to account for the
  absence of key data (i.e., lack of a critical study). FQPA SF = FQPA Safety Factor. PAD = population adjusted
  dose (a = acute, c = chronic). RfD = reference dose. MOE = margin of exposure. LOC = level of concern. N/A =
  not applicable.


[[Page 54966]]

C. Exposure Assessment

    1. Dietary exposure from food and feed uses. In evaluating dietary 
exposure to the herbicide pendimethalin, and its metabolite (CL 
202347), EPA considered exposure under the petitioned-for tolerances as 
well as all existing tolerances for the herbicide pendimethalin, and 
its metabolite (CL 202347) in 40 CFR 180.361. EPA assessed dietary 
exposures from the herbicide pendimethalin, and its metabolite (CL 
202347) in food as follows:
    i. Acute exposure. Quantitative acute dietary exposure and risk 
assessments are performed for a food-use pesticide, if a toxicological 
study has indicated the possibility of an effect of concern occurring 
as a result of a 1-day or single exposure.
    No such effects were identified in the toxicological studies for 
the herbicide pendimethalin, and its metabolite (CL 202347); therefore, 
a quantitative acute dietary exposure assessment is unnecessary.
    ii. Chronic exposure. In conducting this chronic dietary risk 
assessment of the dietary Exposure Evaluation Model (DEEM\TM\) analysis 
evaluated the individual food consumption as reported by respondents in 
the United States Department of Agriculture Nationwide Continuing 
Surveys of Food Intake by Individuals (CSFII) and accumulated exposure 
to the chemical for each commodity (CSFII, 1994-1996, and 1998). 
Tolerance-level residues were assumed for all food commodities with 
current and proposed pendimethalin tolerances, and it was assumed that 
all of the crops included in the analysis were treated (i.e., 100 
percent crop treated (PCT)). These assumptions result in highly 
conservative estimates of dietary exposure and risk.
    iii. Cancer. Pendimethalin is classified as a ``Group C[rdquo,] 
possible human carcinogen, chemical based on a statistically 
significant increased trend and pair-wise comparison between the high 
dose group and controls for thyroid follicular cell adenomas in male 
and female rats. A non-quantitative approach (i.e., non-linear, RfD 
approach) was used by the Agency since mode of action studies are 
available that demonstrate that the thyroid tumors are due to a 
thyroid-pituitary imbalance, and also since pendimethalin was shown to 
be non-mutagenic in mammalian somatic cells and germ cells. The cPAD 
from the 92-day thyroid function study in rats; 56-day thyroid study in 
rats; 14-day intra thyroid metabolism study in rats used for the 
chronic dietary assessment provide adequate protection for the pre-
cancerous effect on the thyroid.
    iv. Anticipated residue and PCT information. EPA did not use 
anticipated residue and/or PCT information in the dietary assessment 
for the herbicide pendimethalin. Tolerance level residues and/or 100 
PCT were assumed for all food commodities.
    2. Dietary exposure from drinking water. The Agency used screening 
level water exposure models in the dietary exposure analysis and risk 
assessment for in drinking water. These simulation models take into 
account data on the physical, chemical, and fate/transport 
characteristics of the herbicide pendimethalin. Further information 
regarding EPA drinking water models used in pesticide exposure 
assessment can be found at http://www.epa.gov/oppefed1/models/water/
index.htm.
    Based on the Pesticide Root Zone Model/Exposure Analysis Modeling 
System (PRZM/EXAMS) and Screening Concentration in Ground Water (SCI-
GROW) models, drinking water concentrations (EDWCs) of the herbicide 
pendimethalin were estimated.
    Modeled estimates of drinking water concentrations were directly 
entered into the dietary exposure model. For acute dietary risk 
assessment, the water concentration value of 77.7 parts per billion 
(ppb) was used to assess the contribution to drinking water.
    For chronic dietary risk assessment, the water concentration of 
value 6 ppb was used to assess the contribution to drinking water.
    3. From non-dietary exposure. The term ``residential exposure'' is 
used in this document to refer to non-occupational, non-dietary 
exposure (e.g., for lawn and garden pest control, indoor pest control, 
termiticides, and flea and tick control on pets).
    Pendimethalin is currently registered for the following residential 
non-dietary sites: Landscape, grounds plantings, ornamental crops, turf 
grass, and lawns. EPA assessed residential exposure using the following 
assumptions: Exposures are short-term in duration, and consist of 
dermal (for adults and children), and oral (hand-to-mouth, object-to-
mouth, and soil ingestion, for children only). The Agency combines risk 
values resulting from separate exposure scenarios when it is likely 
they can occur simultaneously, based on the use-pattern and the 
behavior associated with the exposed population. The LOC for oral, 
dermal and inhalation exposure is an MOE of less than 300. The 
residential exposure estimate for adults, consisting of dermal exposure 
only, results in a total MOE of 740, and is therefore not of concern. 
The residential exposure for children results in a total MOE (dermal + 
oral) of 410 at an application rate of 2 lb ai/acre, and an MOE of 400 
for an application rate of 3 lb ai/acre. Residential aggregate exposure 
is not of concern.
    4. Cumulative effects from substances with a common mechanism of 
toxicity. Section 408(b)(2)(D)(v) of FFDCA 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.''
    Unlike other pesticides for which EPA has followed a cumulative 
risk approach based on a common mechanism of toxicity, EPA has not made 
a common mechanism of toxicity finding as to pendimethalin and any 
other substances and pendimethalin 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 pendimethalin has 
a common mechanism of toxicity with other substances. For information 
regarding EPA's efforts to determine which chemicals have a common 
mechanism of toxicity and to evaluate the cumulative effects of such 
chemicals, see the policy statements released by EPA's Office of 
Pesticide Programs concerning common mechanism determinations and 
procedures for cumulating effects from substances found to have a 
common mechanism on EPA's website at http:// www.epa.gov/pesticides/
cumulative/.

D. Safety Factor for Infants and Children

    1. In general. Section 408(b)(2)(c) of FFDCA provides that EPA 
shall apply an additional tenfold (10X) margin of safety for infants 
and children in the case of threshold effects to account for prenatal 
and postnatal toxicity and the completeness of the database on toxicity 
and exposure unless EPA determines based on reliable data that a 
different margin of safety will be safe for infants and children. This 
additional margin of safety is commonly referred to as the FQPA safety 
factor (SF). In applying this provision, EPA either retains the default 
value of 10X, or uses a different additional safety factor when 
reliable data available to EPA support the choice of a different 
factor.
    2. Prenatal and postnatal sensitivity. The data base for 
pendimethalin does not indicate a potential for increased toxicological 
sensitivity from either prenatal or postnatal exposures. No

[[Page 54967]]

developmental toxicity was observed in either the rat or rabbit 
developmental toxicity studies, nor was there evidence in the 2-
generation reproduction study of developmental or reproductive toxicity 
at dose levels below those in which parental toxicity was observed. 
There was no neurotoxicity observed in the submitted toxicity studies, 
and therefore a developmental neurotoxicity (DNT) study is not 
required.
    3. Conclusion. EPA has determined that the FQPA safety factor of 
10X must be retained. This decision is based on the following findings:
    i. The toxicity database for pendimethalin contains all of the 
standard toxicity studies. However, there is uncertainty regarding 
potential thyroid effects seen in some of these studies. Based on the 
hormonal changes (alterations in thyroid weights and histopathological 
lesions) observed in several studies following oral administration of 
pendimethalin, it is likely that pendimethalin may cause disruption in 
the endocrine system. There is concern that perturbation of thyroid 
homeostasis may lead to hypothyroidism and possibly result in adverse 
effects on the developing nervous system. Consequently, EPA has 
recommended that a developmental thyroid assay be conducted to evaluate 
the impact of pendimethalin on thyroid hormones, structure, and/or 
thyroid hormone homeostasis during development. This study has not yet 
been submitted.
    ii. There is no indication that pendimethalin is a neurotoxic 
chemical and there is no need for a developmental neurotoxicity study 
or additional UFs to account for neurotoxicity.
    iii. There is no evidence that pendimethalin results in increased 
susceptibility in in utero rats or rabbits in the prenatal 
developmental studies or in young rats in the 2-generation reproduction 
study. However, the developmental studies were not adequate to fully 
assess the potential for susceptibility. Consequently, there is concern 
for potential increased sensitivity or susceptibility in offspring 
regarding thyroid effects.
    iv. There are no residual uncertainties identified in the exposure 
databases. The dietary food exposure assessments were performed based 
on 100 PCT and tolerance-level residues. Conservative ground and 
surface water modeling estimates were used. Similarly, conservative 
Residential SOPs were used to assess post-application exposure of 
children as well as incidental oral exposure of toddlers. These 
assessments will not underestimate the exposure and risks posed by 
pendimethalin.
    Although the exposure estimate is very conservative and there are 
no neurotoxic concerns for pendimethalin, there is sufficient 
uncertainty regarding thyroid effects, particularly thyroid effects in 
the young, that EPA is retaining the 10X FQPA safety factor. EPA has 
also determined that the traditional 10X uncertainty factor to account 
for interspecies variation may be reduced to 3X, since it has been 
established that rats are more susceptible to thyroid effects than 
humans. These factors, together with the traditional 10X uncertainty 
factor to account for intraspecies variation, result in a total 
uncertainty factor of 300X (10X, 3X, and 10X).

E. Aggregate Risks and Determination of Safety

    EPA determines whether acute and chronic pesticide exposures are 
safe by comparing aggregate exposure estimates to the aPAD and cPAD. 
The aPAD and cPAD represent the highest safe exposures, taking into 
account all appropriate SFs. EPA calculates the aPAD and cPAD by 
dividing the POD by all applicable UFs. For linear cancer risks, EPA 
calculates the probability of additional cancer cases given the 
estimated aggregate exposure. Short-, intermediate-, and chronic-term 
risks are evaluated by comparing the estimated aggregate food, water, 
and residential exposure to the POD to ensure that the MOE called for 
by the product of all applicable UFs is not exceeded.
    1. Acute risk. No toxic effects attributable to a single dose were 
identified for pendimethalin. Therefore, a quantitative acute risk 
assessment was not conducted for pendimethalin.
    2. Chronic risk. The dietary exposure (food and drinking water) 
pathway is the only source of exposure to pendimethalin that is 
expected to be of long term (180 to 365 days). Therefore, the long-term 
aggregate exposure and risk estimates are equivalent to the chronic 
dietary exposure and risk estimates.
    Using the exposure assumptions described in this unit for chronic 
exposure, EPA has concluded that chronic exposure to the herbicide 
pendimethalin from food and water will utilize 15% of the cPAD for 
(children 1-2 years of age) the population group receiving the greatest 
exposure. Based on the explanation in Unit III.C.3., regarding 
residential use patterns, chronic residential exposure to residues of 
the herbicide pendimethalin is not expected.
    3. Short-term risk. Short-term aggregate exposure takes into 
account short-term residential exposure plus chronic exposure to food 
and water (considered to be a background exposure level).
    The herbicide pendimethalin is currently registered for uses that 
could result in short-term residential exposure and the Agency has 
determined that it is appropriate to aggregate chronic exposure through 
food and water with short-term residential exposures to the herbicide 
pendimethalin.
    Using the exposure assumptions described in this unit for short-
term exposures, EPA has concluded the combined short-term food, water, 
and residential exposures aggregated result in aggregate MOEs of the 
level of concern for oral, dermal, and inhalation exposure is an MOE of 
less than 300. The short-term aggregate exposure estimate for adult 
males results in an aggregate MOE of 650, while the short-term 
aggregate exposure estimate for adult females results in an aggregate 
MOE of 580. The aggregate exposure estimate for children results in a 
total MOE of 350 at an application rate (to residential turf) of 2 lbs 
ai/A, and a total MOE of 340 for an application rate of 3 lbs ai/A. 
Aggregate exposure is therefore not of concern for any of the 
population subgroups.
    4. Intermediate-term risk. Intermediate-term aggregate exposure 
takes into account intermediate-term residential exposure plus chronic 
exposure to food and water (considered to be a background exposure 
level).
    The herbicide pendimethalin is not registered for any use patterns 
that would result in intermediate-term residential exposure. Therefore, 
the intermediate-term aggregate risk is the sum of the risk from 
exposure to the herbicide pendimethalin through food and water, which 
has already been addressed, and will not be greater than the chronic 
aggregate risk.
    5. Aggregate cancer risk for U.S. population. EPA classified 
pendimethalin as a ``Group C'' (possible human) carcinogen based on a 
statistically significant increased trend and pair-wise comparison 
between the high dose group and controls for thyroid follicular cell 
adenomas in male and female rats. EPA is following a non-quantitative 
approach since mode of action studies are available that demonstrate 
that the thyroid tumors are due to a thyroid-pituitary imbalance, and 
also since pendimethalin was shown to be non-mutagenic in mammalian 
somatic cells and germ cells. The chronic risk assessment is considered 
to be protective of any

[[Page 54968]]

cancer effects; therefore, a separate quantitative cancer aggregate 
risk assessment was not conducted.
    6. Determination of safety. Based on these risk assessments, EPA 
concludes that there is a reasonable certainty that no harm will result 
to the general population, or to infants and children from aggregate 
exposure to the herbicide pendimethalin residues.

IV. Other Considerations

A. Analytical Enforcement Methodology

    Adequate methods are available for data collection and tolerance 
enforcement for existing and proposed uses of pendimethalin. Methods I 
through IV in the Pesticide Analytical Manuel (PAM) Vol. II are gas 
chromatography/electron capture (GC/ECD) methods. Methods used for data 
collection are essentially the same as the PAM Vol. II methods, and 
have been adequately validated.
    The Food and Drug Administration's PESTDATA data base (PAM Volume 
I, Appendix I) indicates that pendimethalin is completely recovered 
(>80%) by Multiresidue Methods Section 302 (Luke Method; Protocol D) 
and 303 (Mills, Onley, Gaither Method; Protocol E, nonfatty), and 
partially recovered (50-80%) by Multiresidue Method Section 304 (Mills 
Fatty Food Method; Protocol E, fatty).
    Adequate enforcement methodology liquid chromatography/mass 
spectrometry (LC/MS/MS) is available to enforce the tolerance 
expression. The method may be requested from: Chief, Analytical 
Chemistry Branch, Environmental Science Center, 701 Mapes Rd., Ft. 
Meade, MD 20755-5350; telephone number: (410) 305-2905; e-mail address: 
residuemethods@epa.gov.

B. International Residue Limits

    There are no established or proposed Codex Maxium Residue Levels 
(MRLs) for pendimethalin residues. Therefore, there are no questions of 
compatibility with respect to Codex MRLs and U.S. tolerances.

C. Revisions to Petitioned-For Tolerances

    Based on the submitted data, residues of pendimethalin in rice 
processed commodities are not expected to exceed those found in rice 
grain. Therefore, a tolerance for rice processing fraction at 0.1 ppm 
is not necessary.

V. Conclusion

    Therefore, tolerances are established for combined residues of the 
herbicide pendimethalin, N-(1-ethylpropyl)-3,4-dimethyl-2,6- dinitro-
benzenamine, and its metabolite, 4-[(1-ethylpropyl) amino]-2-methyl-
3,5-dinitrobenzyl alcohol, in or on cotton, gin byproducts at 3.0 ppm, 
and crayfish at 0.05 ppm.

VI. Statutory and Executive Order Reviews

    This final rule establishes tolerances under section 408(d) of 
FFDCA 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). Because this final rule has been 
exempted from review under Executive Order 12866, this final rule is 
not subject to Executive Order 13211, entitled Actions Concerning 
Regulations That Significantly Affect Energy Supply, Distribution, or 
Use (66 FR 28355, May 22, 2001) or Executive Order 13045, entitled 
Protection of Children from Environmental Health Risks and Safety Risks 
(62 FR 19885, April 23, 1997). 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., nor does it require any 
special considerations under Executive Order 12898, entitled Federal 
Actions to Address Environmental Justice in Minority Populations and 
Low-Income Populations (59 FR 7629, February 16, 1994).
    Since tolerances and exemptions that are established on the basis 
of a petition under section 408(d) of FFDCA, 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.
    This final rule directly regulates growers, food processors, food 
handlers, and food retailers, not States or tribes, nor does this 
action alter the relationships or distribution of power and 
responsibilities established by Congress in the preemption provisions 
of section 408(n)(4) of FFDCA. As such, the Agency has determined that 
this action will not have a substantial direct effect on States or 
tribal governments, on the relationship between the national government 
and the States or tribal governments, or on the distribution of power 
and responsibilities among the various levels of government or between 
the Federal Government and Indian tribes. Thus, the Agency has 
determined that Executive Order 13132, entitled Federalism (64 FR 
43255, August 10, 1999) and Executive Order 13175, entitled 
Consultation and Coordination with Indian Tribal Governments (65 FR 
67249, November 9, 2000) do not apply to this final rule. In addition, 
this final rule does not impose any enforceable duty or contain any 
unfunded mandate as described under Title II of the Unfunded Mandates 
Reform Act of 1995 (UMRA) (Public Law 104-4).
    This action does not involve any technical standards that would 
require Agency consideration of voluntary consensus standards pursuant 
to section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (NTTAA), Public Law 104-113, section 12(d) (15 U.S.C. 272 
note).

VII. Congressional Review Act

    The Congressional Review Act, 5 U.S.C. 801 et seq., generally 
provides that before a rule may take effect, the agency promulgating 
the rule must submit a rule report to each House of the Congress and to 
the Comptroller General of the United States. EPA will submit 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 
United States prior to publication of this final rule in the Federal 
Register. This final rule 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: September 9, 2008.
Donald R. Stubbs,
Acting Director, Registration Division, Office of Pesticide Programs.

0
Therefore, 40 CFR chapter I is amended as follows:

PART 180--[AMENDED]

0
1. The authority citation for part 180 continues to read as follows:

    Authority: 21 U.S.C. 321(q), 346a and 371.


0
2. Section 180.361 is amended by alphabetically adding the following 
commodities to the table in paragraph (a) to read as follows:


Sec.  180.361  Pendimethalin, tolerance for residues.

    (a) * * *

------------------------------------------------------------------------
                      Commodity                        Parts per million
------------------------------------------------------------------------
                                * * * * *
Cotton, gin byproducts...............................                3.0
                                * * * * *
Crayfish.............................................               0.05
                                * * * * *
------------------------------------------------------------------------


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* * * * *

[FR Doc. E8-22434 Filed 9-23-08; 8:45 am]

BILLING CODE 6560-50-S
