Document ID: EPA-HQ-OPP-2006-0559-0006
Agency: epa
Document Type: Rule
Title: Diuron; Pesticide Tolerance
Posted Date: 2007-06-13T04:00Z

[Federal Register: June 13, 2007 (Volume 72, Number 113)]
[Rules and Regulations]               
[Page 32533-32540]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr13jn07-9]                         

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[EPA-HQ-OPP-2006-0559; FRL-8133-2]

 
Diuron; Pesticide Tolerance

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes tolerances for diuron in or on 
cactus (with regional restrictions for use); spearmint, tops; 
peppermint, tops; and fish-freshwater finfish, farm raised. 
Interregional Research Project Number 4 (IR-4) and the Catfish Farmers 
of America requested these tolerances under the Federal Food, Drug, and 
Cosmetic Act (FFDCA).

DATES: This regulation is effective June 13, 2007. Objections and 
requests for hearings must be received on or before August 13, 2007, 
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-2006-0559. 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 web site 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

[[Page 32534]]

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: Barbara Madden, Registration Division 
(7505P), Office of Pesticide Programs, Environmental Protection Agency, 
1200 Pennsylvania Ave., NW., Washington, DC 20460-0001; telephone 
number: (703) 305-6463; e-mail address: madden.barbara@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), e.g., agricultural 
workers; greenhouse, nursery, and floriculture workers; farmers.
     Animal production (NAICS code 112), e.g., cattle ranchers 
and farmers, dairy cattle farmers, livestock farmers.
     Food manufacturing (NAICS code 311), e.g., agricultural 
workers; farmers; greenhouse, nursery, and floriculture workers; 
ranchers; pesticide applicators.
     Pesticide manufacturing (NAICS code 32532), e.g., 
agricultural workers; commercial applicators; farmers; greenhouse, 
nursery, and floriculture workers; residential users.
    This listing is not intended to be exhaustive, but rather to 
provide a guide 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 the 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-2006-0559 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 August 13, 2007.
    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-2006-0559, 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 July 26, 2006 (71 FR 42390) (FRL-8079-
4), EPA issued a notice pursuant to section 408(d)(3) of FFDCA, 21 
U.S.C. 346a(d)(3), announcing the filings of a pesticide petitions (PP 
2E6438, 6E3390 and 6F4680) by Interregional Research Project Number 4 
(IR-4), 681 Highway 1 South, North Brunswick, NJ 08902 and the Catfish 
Farmers of America, 1100 Hwy. 82 East, Suite 202, Indianola, MS 38751. 
The petitions requested that 40 CFR 180.106 be amended by establishing 
tolerances for residues of the herbicide diuron (3-(3,4-
dichlorophenyl)-1,1-dimethylurea in or on cactus, prickly pear at 0.05 
part per million (ppm) (6E3390), mint at 1.5 ppm (2E6438) and 
freshwater finfish, farm raised at 2.0 ppm (6F4680). That notice 
referenced a summary of the petitions prepared by Dupont, the 
registrant, which is available to the public in the docket, http://www.regulations.gov.
 Comments received on the notice of filing are 

discussed in Unit IV.C.
    Based upon review of the data supporting the petition, EPA has 
recommended certain changes to the petitions including:
    1. Revised tolerance levels for certain commodities;
    2. A revised tolerance expression to be applied to all new uses; 
and
    3. Revised commodity terms for some commodities.
The reasons for these changes are explained in Unit V.

III. Aggregate Risk Assessment and Determination of Safety

    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) of the 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 the 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....'' These provisions were added to the FFDCA by the Food 
Quality Protection Act (FQPA) of 1996.
    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

[[Page 32535]]

and to make a determination on aggregate exposure for the petitioned-
for tolerance for combined residues of diuron (3-(3,4-dichlorophenyl)-
1,1-dimethylurea and its metabolites convertible to 3,4-dichloroaniline 
on cactus at 0.05 ppm, spearmint, tops at 1.5 ppm, peppermint, tops at 
1.5 ppm and fish - freshwater finfish, farm raised at 2.0 ppm. EPA's 
assessment of 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. Specific information on the studies received and the nature 
of the adverse effects caused by diuron as well as the no-observed-
adverse-effect-level (NOAEL) and the lowest-observed-adverse-effect-
level (LOAEL) from the toxicity studies can be found at http://www.regulations.gov.
 The referenced document is available in the docket 

established by this action, which is described under ADDRESSES, and is 
identified as EPA-HQ-OPP-2006-0059. Additional information regarding 
this chemical can also be found in the docket for the reregistration 
eligibility decision (RED) for diuron identified as EPA-HQ-OPP-2002-
0249.
    Diuron has low acute toxicity (Toxicity Category 3-4) by the oral, 
dermal, or inhalation exposure routes. Diuron is not an eye or skin 
irritant, and not a skin sensitizer. The primary target organs are the 
hematopoietic system, the bladder, and renal pelvis. Erythrocyte damage 
resulted in hemolytic anemia and compensatory hematopoiesis, which were 
manifested as significantly decreased erythrocyte counts, hemoglobin 
levels, and hematocrit, and increased mean corpuscular volume (MCV), 
mean corpuscular hemoglobin (MCH), abnormal erythrocyte forms, 
reticulocyte counts, and leukocyte count. Consistent observations of 
erythrocytic regeneration were seen in chronic toxicity studies in 
rats, mice and dogs. Gross pathology findings in chronic rat and mouse 
studies showed increased incidences of urinary bladder edema and wall 
thickening at high doses. Microscopic evaluation showed dose-related 
increases in the severity of epithelial focal hyperplasia of the 
urinary bladder and renal pelvis in both sexes. The available data did 
not reveal any developmental or reproductive toxicity. The 
Carcinogenicity Peer Review Committee (CPRC) characterized diuron as a 
``known/likely'' human carcinogen based on urinary bladder carcinomas 
in both sexes of the Wistar rat, kidney carcinomas in the male rat, and 
mammary gland carcinomas in the female NMRI mouse. Diuron was not 
mutagenic in bacteria or in cultured mammalian cells and no indication 
of DNA damage in primary rat hepatocytes was observed. There were 
marginal statistically significant increases in cells with structural 
aberrations in a Sprague Dawley rat in vivo bone marrow chromosomal 
aberration assay. However, the levels of aberrations were within 
historical control range and assessed negative.
    The Metabolism Assessment Review Committee (MARC) recommended that 
a separate dietary cancer assessment be conducted for N'-(3-
chlorophenyl)-N,N-dimethyl urea (MCPDMU), a potential residue of 
concern in drinking water, but not found in food (in plant or animal 
metabolism studies). The MARC raised concerns for MCPDMU based on an 
analogous compound, N'-(4-chlorophenyl)-N,N-dimethyl urea (monuron). 
With the exception of the position of the chlorine, the structures are 
identical. There are cancer concerns for monuron but the target organs 
are different than those affected by diuron. In the absence of the data 
needed for a more comprehensive evaluation of MCPDMU, the carcinogenic 
risk assessment was conducted using the Q1* of monuron.

B. Toxicological Endpoints

    For hazards that have a threshold below which there is no 
appreciable risk, the toxicological level of concern (LOC) is derived 
from 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) is 
sometimes used for risk assessment. Uncertainty/safety factors (UF) are 
used in conjunction with the LOC 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 
risks by comparing aggregate 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 LOC 
by all applicable uncertainty/safety factors. Short-, intermediate, and 
long-term risks are evaluated by comparing aggregate exposure to the 
LOC to ensure that the margin of exposure (``MOE'') called for by the 
product of all applicable uncertainty/safety factors is not exceeded.
    For non-threshold risks, the Agency assumes that any amount of 
exposure will lead to some degree of risk and estimates risk in terms 
of the probability of occurrence of additional adverse cases. 
Generally, cancer risks are considered non-threshold. 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/fedrgstr/EPA-PEST/1997/November/Day-26/p30948.htm
.

    A summary of the toxicological endpoints for diruon used for human 
risk assessment can be found at http://www.regulations.gov in document Diuron. 

Updated Aggregate Risk Assessment to Support Permanent Tolerances for 
Residues in Prickly Pear Cactus, Peppermint Tops, Spearmint Tops, and 
Freshwater Finfish, Farm-Raised at page 4 in Docket ID EPA-HQ-OPP-2006-
0059.
    There are no adverse effects attributed to a single exposure 
identified in any available studies for diuron. In addition, diuron has 
low acute toxicity and no developmental or neurotoxic concerns. 
Therefore, no acute dietary endpoint was chosen and no acute dietary 
risk assessment was conducted. Also, no systemic toxicity was observed 
following repeated dermal dosing up to 1,200 mg/kg/day. Therefore, no 
short- or intermediate-term dermal endpoints were chosen either. The 
short-term incidental oral and the inhalation endpoints are based on 
decreased maternal body weight and food consumption observed in a 
rabbit developmental toxicity study [No Observable Adverse Effect Level 
(NOAEL) = 10 mg/kg/day]. The intermediate-term incidental oral and 
intermediate-term inhalation endpoints are based on hematological 
effects observed at 10 mg/kg at 6 months in the chronic rat study. The 
NOAEL is 1 mg/kg/day. The chronic dietary, and long-term dermal and 
inhalation endpoints are based on hemolytic anemia and compensatory 
hematopoiesis [Lowest Observable Adverse Effect Level (LOAEL) = 1.0 mg/
kg/day]. Since the dose and endpoint for establishing the chronic 
dietary reference Dose (RfD) is a LOAEL and a NOAEL was not 
established, a total uncertainty factor (UF) of 1,000 was applied (a UF 
of 100 to account for both interspecies extrapolation and intra-species

[[Page 32536]]

variability and an UF of 10 since the 10X FQPA safety factor has been 
retained to protect infants and children). A low dose linear 
extrapolation model with a Q1* of 1.91 x 10-\2\ 
(mg/kg/day)-\1\was applied to the animal data for the 
quantification of human risk to diuron, based on the urinary bladder 
carcinomas in the rat.
    As discussed in Unit III.A., a separate dietary cancer assessment 
was conducted for N'-(3-chlorophenyl)-N,N-dimethyl urea (MCPDMU), a 
potential residue of concern in drinking water, but not found in food. 
A low dose linear extrapolation model with a Q1* of 1.52 x 
10-\2\ (mg/kg/day)-\1\ was applied to the animal 
data for the quantification of human risk, based on male rat liver 
neoplastic nodule and/or carcinoma combined tumor rates.

C. Exposure Assessment

    1. Dietary exposure from food and feed uses. In evaluating dietary 
exposure to diuron, EPA considered exposure under the petitioned-for 
tolerances as well as all existing diuron tolerances in (40 CFR 
180.106). EPA assessed dietary exposures from diuron and its 
metabolites convertible to 3,4-dichloroaniline 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 one-day or single exposure.
    No such effects were identified in the toxicological studies for 
diuron; therefore, a quantitative acute dietary exposure assessment is 
unnecessary.
    ii. Chronic exposure. In conducting the chronic dietary exposure 
assessment EPA used the food consumption data from the USDA 1994-1996 
and 1998 Nationwide Continuing Surveys of Food Intake by Individuals 
(CSFII). As to residue levels in food, the EPA analyses incorporated 
tolerance level residues for some commodities as well as anticipated 
residues (ARs) for other commodities, based on a combination of average 
field trial data and USDA/Pesticide Data Program (PDP) monitoring data. 
The chronic exposure estimates were further refined with percent crop 
treated (PCT) information for some crops. In some cases, DEEM\(TM)\ 
(ver. 7.78) default processing factors were used, but empirical 
processing factors were used when available.
    iii. Cancer. --a. Diuron. In conducting the cancer dietary exposure 
assessment EPA used the food consumption data from the USDA 1994-1996 
and 1998 Nationwide Continuing Surveys of Food Intake by Individuals 
(CSFII). As to residue levels in food, the EPA analyses incorporated 
tolerance level residues for some commodities as well as anticipated 
residues (ARs) for other commodities, based on a combination of average 
field trial data and USDA PDP monitoring data. The cancer exposure 
estimates were further refined with PCT information for some crops. In 
some cases, DEEM\(TM)\ (ver. 7.78) default processing factors were 
used, but empirical processing factors were used when available.
    b. MCPDMU. EPA has identified MCPDMU as a potential residue of 
concern of diuron that may be found in drinking water but not found in 
food. In the absence of a metabolism study in fish, based on potential 
concern for residues of the drinking water, EPA conducted an assessment 
based on a worst-case dietary exposure analysis for the degradate 
MCPDMU, including residues in drinking water and a conservative 
estimate of potential residues in fish. EPA estimated the MCPDMU 
drinking water residue value of 1 ppb, based on monitoring data and 
assumed 25% (i.e., 0.5 ppm) of the residue in fish could be attributed 
to the degradate. This is a conservative assumption of a 500-fold 
accumulation of the degradate in fish, whereas acceptable metabolism 
studies in rat, ruminants and poultry indicate the majority of the 
residue in animals consists of dichlorinated and hydroxy metabolites; 
further, the rat metabolism study indicates diuron residues do not 
bioaccumulate. Therefore, the assumption that 25% of the tolerance-
level residue in fish is comprised of the MCPDMU degradate is 
considered to be conservative.
    iv. Anticipated residue and PCT information. Section 408(b)(2)(E) 
of the FFDCA authorizes EPA to use available data and information on 
the anticipated residue levels of pesticide residues in food and the 
actual levels of pesticide residues that have been measured in food. If 
EPA relies on such information, EPA must pursuant to section 408(f)(1) 
of FFDCA require that data be provided 5 years after the tolerance is 
established, modified, or left in effect, demonstrating that the levels 
in food are not above the levels anticipated. For the present action, 
EPA will issue such data call-ins as are required by section 
408(b)(2)(E) of FFDCA and authorized under section 408(f)(1) of FFDCA. 
Data will be required to be submitted no later than 5 years from the 
date of issuance of this tolerance.
    Section 408(b)(2)(F) of the FFDCA states that the Agency may use 
data on the actual percent of food treated for assessing chronic 
dietary risk only if:
    a. The data used are reliable and provide a valid basis to show 
what percentage of the food derived from such crop is likely to contain 
such pesticide residue;
    b. The exposure estimate does not underestimate exposure for any 
significant subpopulation group; and
    c. Data are available on pesticide use and food consumption in a 
particular area, the exposure estimate does not understate exposure for 
the population in such area. In addition, the Agency must provide for 
periodic evaluation of any estimates used. To provide for the periodic 
evaluation of the estimate of PCT as required by section 408(b)(2)(F) 
of FFDCA, EPA may require registrants to submit data on PCT.
    The Agency used PCT information as follows:
    1% alfalfa, 1% almonds, 10% apples, 5% artichokes, 55% asparagus, 
1% barley, 50% blackberries, 30% blueberries, 1% corn, 25% cotton, 20% 
filberts, 10% grapes, 45% grapefruit, 15% lemon, 50% limes, 20% 
Macadamia nut, 5% oats, 15% olives, 50% oranges, 10% peaches, 10% 
pears, 5% pecans, 90% mint, 1% pistachios, 30% raspberries, 15% 
sugarcane, 30% tangerines, 15% walnuts, and 1%wheat.
    EPA uses an average PCT for chronic dietary risk analysis. The 
average PCT figure for each existing use is derived by combining 
available federal, state, and private market survey data for that use, 
averaging by year, averaging across all years, and rounding up to the 
nearest multiple of five percent except for those situations in which 
the average PCT is less than one. In those cases < 1% is used as the 
average and < 2.5% is used as the maximum. EPA uses a maximum PCT for 
acute dietary risk analysis. The maximum PCT figure is the single 
maximum value reported overall from available federal, state, and 
private market survey data on the existing use, across all years, and 
rounded up to the nearest multiple of five percent. In most cases, EPA 
uses available data from United States Department of Agriculture/
National Agricultural Statistics Service (USDA/NASS), Proprietary 
Market Surveys, and the National Center for Food and Agriculture Policy 
(NCFAP) for the most recent six years.
    There are existing tolerances for residues of diuron on peppermint, 
hay at 2 ppm. However, the EPA has determined the preferred commodity 
term should be peppermint, tops. Therefore, the PCT estimates used for 
mint are based on the existing registration and are not projections.

[[Page 32537]]

    The Agency believes that the three conditions listed in Unit 
III.C.iv. have been met. With respect to Condition 1, PCT estimates are 
derived from Federal and private market survey data, which are reliable 
and have a valid basis. The Agency is reasonably certain that the 
percentage of the food treated is not likely to be an underestimation. 
As to Conditions 2 and 3, regional consumption information and 
consumption information for significant subpopulations is taken into 
account through EPA's computer-based model for evaluating the exposure 
of significant subpopulations including several regional groups. Use of 
this consumption information in EPA's risk assessment process ensures 
that EPA's exposure estimate does not understate exposure for any 
significant subpopulation group and allows the Agency to be reasonably 
certain that no regional population is exposed to residue levels higher 
than those estimated by the Agency. Other than the data available 
through national food consumption surveys, EPA does not have available 
information on the regional consumption of food to which diuron may be 
applied in a particular area.
    2. Dietary exposure from drinking water. The drinking water 
exposure assessment conducted in conjunction with the 2003 RED noted 
that surface water monitoring data resulted in diuron residues less 
than 1 parts per billion (ppb) (http://www.regulations.gov, document 

0006 - Docket ID EPA-HQ-OPP-2002-0249). For ground water, modeling 
results indicted that residues of diuron and degradates would be at 
most 0.6 ppb for long-term exposure assessment. For the current 
assessment, EPA used PDP monitoring data from 2003 and 2004, in which 
1,072 samples of raw and treated water were analyzed for diuron 
residues. Residues were detected in 12 samples, ranging from 27 to 267 
parts per trillion (ppt), with an average of 20.2 ppt (0.020 ppb). For 
chronic dietary risk assessment, the water concentration of value 0.020 
ppb was used to access the contribution to drinking water. These 
estimates of drinking water concentrations were directly entered into 
the dietary exposure model.
    The drinking water exposure assessment conducted in conjunction 
with the 2003 RED noted that surface water monitoring data resulted in 
diuron residues less than 1 ppb. For ground water, modeling results 
indicated that residues of diuron and degradates would be at most 0.6 
ppb for long-term exposure assessment. The analysis in the RED noted 
that the potential for residues in drinking water sources is more 
likely to occur from run-off to surface water, and the ground water 
sources of drinking water are likely to be less vulnerable to 
contamination with diuron. The RED cited numerous monitoring studies 
from areas known for high diuron usage. The drinking water risks in the 
RED were calculated from diuron residues in a Florida surface water 
monitoring study in which the highest residue found was 1.2 ppb, but 
the 90\th\ and 95\th\ percentile residues were both less than the limit 
of detection in the study, which ranged from 0.2 to 0.4 ppb. For the 
current assessment, drinking water residues were estimated from PDP 
monitoring data from 2003 and 2004, in which 1,072 samples of raw and 
treated water were analyzed for diuron residues. Residues were detected 
in 12 samples, ranging from 27 to 267 ppt, with an average detected 
residue of 20.2 ppt (0.02 ppb). This average of detected residues was 
considered to be more appropriate for estimating cancer risk from 
drinking water than a high-end estimate of surface water residues from 
the Florida monitoring data. However, the 2 sets of monitoring data 
support the conclusion that potential residues in surface water are 
much less than 1 ppb.
    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).
    In conjunction with the RED, the agency concluded that all 
registered uses were eligible for reregistration, provided labeling 
requirements and mitigation measures were observed. This included 
voluntary cancellation of uses allowing application to home lawns. 
Currently, all registered labels for diuron no longer allow 
applications to home lawns. As a result the current uses registered 
that could result in non-occupational, non-dietary exposures are diruon 
added to paints and stains and residential ponds and aquariums.
    Exposures of concern to diuron resulting from residential uses is 
expected to be negligible. The existing residential uses for diuron 
result in only short-term exposures, generally less than 7 days. No 
short-term dermal endpoints have been identified for diuron. A short-
term incidental oral endpoint was identified. However, all residential 
uses to home lawns have been cancelled so incidental oral exposures are 
not expected. Inhalation endpoints have been identified for diuron. 
However, diuron has a low vapor pressure (2 x 10-\7\ mm 
Hg@30[deg]C) and therefore, absorption by the inhalation route is 

likely to be low. Potential residential handler exposures from applying 
paints and stains containing diuron were assessed in the 2003 RED. 
Conservative assumptions included 2 days of painting per year for 50 
years of a 70 year lifetime. However, based on information gathered 
through the RED process it was determined that less than 1% of paint 
sold contains diuron, and that such paints would likely only be used in 
rooms subject to high moisture (e.g., bathrooms). Therefore, lifetime 
exposure to home applicators of diuron-containing products is likely to 
negligible. Postapplication inhalation exposure resulting from the use 
of diuron in residential ponds and aquariums is also expected to be 
minimal based on the extremely high dilution rate. Therefore, an 
exposure assessment was not conducted for non-occupational, non-dietary 
exposures.
    4. Cumulative effects from substances with a common mechanism of 
toxicity. Section 408(b)(2)(D)(v) of the 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.''
    Based on available data, EPA has previously concluded that diuron, 
propanil and linuron, all of which contain 3,4 dichloroaniline (3,4-
DCA) in their structures, do not share a common mechanism of toxicity. 
(Additional information regarding this conclusion can be found in the 
docket for the RED for diuron identified as EPA-HQ-OPP-2002-0249.)
    Propanil readily metabolizes to 3,4-DCA, but neither diuron nor 
linuron metabolize to 3,4-DCA in plant or animal metabolism studies. 
EPA previously recommended against aggregating residues of 3,4 DCA for 
the propanil and diuron risk assessments. The following considerations 
support the recommendation:
     3,4-DCA is a significant residue of concern for propanil, 
but is not a residue of concern per se for diuron;
     The analytical method for quantifying residues of concern 
from applications of diuron converts all residues to 3,4-DCA as a 
technical convenience. However, 3,4-DCA is not a significant residue in 
diuron plant and animal metabolism or hydrolysis studies. Therefore, 
the agency determined that all residues hydrolyzable to 3,4-DCA would 
be included in the tolerance expression for

[[Page 32538]]

diuron, because no validated enforcement method is available for 
quantification for the actual residues of concern for diuron.
     Propanil and its metabolite 3,4-DCA were found to induce 
methemoglobinemia, the endpoint of concern for propanil. Diuron has not 
been shown to cause this effect. Diuron induces hemolytic anemia and 
compensatory hematopoiesis, which are mechanistically different from 
methemoglobinemia.
     Linuron and diuron metabolism studies show that both 
chemicals metabolize to DCPU and DCPMU. However, for reasons that are 
yet unknown, these chemicals do not induce the same toxic effects in 
mammals. Submitted data indicate that diuron is primarily (though not 
exclusively) metabolized by the hydroxylation of the urea group in 
either the methyl or the amino position and conjugated. Linuron, on the 
other hand, appears to be primarily ring-hydroxylated and conjugated. 
The methoxy group is removed, followed by the methyl group, with ring 
hydroxylation. Unlike linuron, hydroxylation of the phenyl ring is not 
a major metabolite pathway of diuron and, both methyl groups are lost.
     Methemoglobinemia is the dominant toxic effect of concern 
for linuron. As mentioned above, diuron does not induce 
methemoglobinemia. Mechanistic and reproductive studies show that 
linuron, and to some extent propanil, is an androgen receptor 
antagonist and that linuron induces testicular abnormalities in 
rodents. Studies with diuron showed no indications of any endocrine 
effects and no developmental or reproductive effects.
     Although the mechanisms of action for the differing 
effects induced by the two ureas, diuron and linuron, are not entirely 
known, there is sufficient cause to believe that exposures from the two 
compounds should not be cumulated.
     The estimated dietary cancer risk for diuron did not 
include residues from linuron and propanil since it was recognized that 
the target organs for tumor induction for diuron are different from 
those for linuron and propanil, and data were available which indicated 
that the mechanism of action may be different for diuron.
    For the purposes of this tolerance action, therefore, EPA has not 
assumed that diuron 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 of FFDCA provides that EPA shall apply 
an additional (``10X'') tenfold 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 data base 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. In applying this provision, EPA either retains the default 
value of 10X when reliable data do not support the choice of a 
different factor, or, if reliable data are available, EPA uses a 
different additional FQPA safety factor value based on the use of 
traditional uncertainty/safety factors and/or special FQPA safety 
factors, as appropriate.
    2. Prenatal and postnatal sensitivity. There is an acceptable 
developmental toxicity study in rabbits and an acceptable 2-generation 
reproduction study in rats. A developmental toxicity study in rats was 
classified as unacceptable due to deficiencies in analytical data on 
the sample analysis; however, the EPA considers the developmental 
toxicity study in rats adequate for the FQPA susceptibility assessment 
based on the observation that the developmental toxicity NOAEL was 
higher than the maternal NOAEL. The EPA has also concluded that a 
developmental neurotoxicity (DNT) study is not required.
    There is no indication of increased susceptibility to young exposed 
to diuron in the available studies. In the developmental toxicity study 
in rabbits, there were no developmental effects at the highest dose 
tested. In the developmental toxicity study in rabbits and in the 2-
generation rat reproduction study, developmental/offspring effects were 
observed only at maternally/parentally toxic dose levels.
    There are no neurotoxic signs in any of the submitted subchronic or 
chronic studies.
    3. Conclusion. The chronic dietary endpoint for diuron used in risk 
assessment is based on a LOAEL of 1 mg/kg/day from the chronic 
toxicity/carcinogenicity study in rats. EPA has retained the 10X FQPA 
safety factor for diuron because of reliance on a LOAEL in the rat 
chronic toxicity study and because the data in that study or other 
studies did not show that a smaller factor would be safe. EPA has 
determined that reliable data show that it would be safe for infants 
and children provided the FQPA safety factor of 10X is retained and no 
additional safety factors are needed. That decision is based on the 
following findings:
    i. There are no uncertainties with the toxicology database other 
than with regard to the lack of a NOAEL in the rat chronic toxicity 
study. The only outstanding toxicity data requirement for diuron is a 
28-day inhalation study which is required to address the concern for 
inhalation exposure to workers during the application of diuron. 
Occupational exposures are not considered under section 408 of FFDCA. 
Postapplication inhalation exposure resulting from the indoor use of 
diuron in paints is expected to be minimal because of the low vapor 
pressure of diuron, and because diuron-treated paint is only likely to 
be used in rooms where high humidity is expected (e.g... a bathroom), 
and would rarely be used in the entire house based on the use pattern. 
Additionally, based on information gathered through the RED process it 
was determined that less than 1% of paint sold contains diuron. As a 
result, non-occupational exposure to diuron via inhalation is not 
expected to occur with infants and children. Therefore, the 28-day 
inhalation study will not change the endpoints used in risk assessment 
to address the potential risks to infants and children.
    The developmental toxicity study in rats is classified as 
unacceptable due to deficiencies in analyses of the test material and 
dosing solutions. However, the EPA has not required the study be 
repeated since it is considered adequate for the FQPA susceptibility 
assessment based on the observation that the developmental toxicity 
NOAEL was higher than the maternal NOAEL, and because maternal and 
developmental toxicity were well-defined at their respective LOAELs. 
Finally, the rabbit is considered to be the more sensitive species than 
the rat for developmental toxicity, and the rabbit developmental study 
is acceptable. The chronic toxicity study in dogs has also been 
classified as unacceptable due to the purity of the test material, as 
well as potential problems with stability and homogeneity issues 
related to the test material. However, the EPA determined that a 
repeated chronic dog study is not required; similar effects were 
observed in rats and dogs, but the effects in the

[[Page 32539]]

rat occurred at lower doses and the rat NOAEL serves as the dose for 
risk assessment. Therefore, the EPA concluded that a new chronic dog 
study would not change the endpoint chosen for risk assessment.
    The data base as a whole is adequate for pre- and post-natal 
toxicity evaluation.
    ii. There is no indication of quantitative or qualitative increased 
susceptibility of rats or rabbits to in utero or postnatal exposure. 
There is no indication of increased susceptibility to young exposed to 
diuron in the available studies. In the developmental toxicity study in 
rabbits, there were no developmental effects at the highest dose 
tested. In the developmental toxicity study in rabbits and in the 2-
generation rat reproduction study, developmental/offspring effects were 
observed only at maternally/parentally toxic dose levels.
    iii. There are no neurotoxic signs in any of the submitted 
subchronic or chronic studies. A developmental neurotoxicity study 
(DNT) for diuron is not required.
    iv. There are no residual uncertainties identified in the exposure 
databases. The dietary (food and drinking water) and non-dietary 
(residential) exposure assessments will not underestimate the potential 
exposures for infants and children. The dietary food exposure 
assessments were performed based on reliable field trial data where 
tolerance level residues for some commodities as well as anticipated 
residues (ARs) for other commodities, based on a combination of average 
field trial data and USDA/PDP monitoring data. Average PCT values were 
assumed for chronic dietary assessment for some crops and 100 PCT 
treated were assumed for the remaining uses. Drinking water estimates 
were based on monitoring studies and USDA/PDP monitoring data. EPA 
expects any residential exposure from use of diuron to be negligible. 
The EPA is confident that these assessments will not underestimate the 
exposure and risks posed by diuron.

E. Aggregate Risks and Determination of Safety

    Safety is assessed for acute and chronic risks by comparing 
aggregate 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 LOC by all applicable 
uncertainty/safety factors. For linear cancer risks, EPA calculates the 
probability of additional cancer cases given aggregate exposure. Short-
, intermediate, and long-term risks are evaluated by comparing 
aggregate exposure to the LOC to ensure that the margin of exposure 
(``MOE'') called for by the product of all applicable uncertainty/
safety factors is not exceeded.
    1. Acute risk. As there were no toxic effects attributable to a 
single dose, an endpoint of concern was not identified to quantitate 
acute-dietary risk to the general population or to the subpopulation 
females 13-50 years old. No acute risk is expected from exposure to 
diuron.
    2. Chronic risk. Using the exposure assumptions described in this 
unit for chronic exposure, EPA has concluded that exposure to diruon 
from food and water will utilize 19% of the cPAD for the population 
group children 1-2 years old, the subpopulation group with greatest 
exposure. There are no residential uses for diuron that result in 
chronic residential exposure to diuron.
    3. Short-term risk and Intermediate risk. Short-term and 
intermediate-term aggregate exposure takes into account residential 
exposure plus chronic exposure to food and water (considered to be a 
background exposure level). The current uses registered that could 
result in non-occupational, non-dietary exposures are from diuron added 
to paints and stains as well as applications to residential ponds and 
aquariums. However, EPA expects any residential exposure from use of 
diuron to be negligible. Therefore, no short-term and intermediate-term 
risk is expected from exposure to diuron as a result of non-occupation, 
non-dietary exposures.
    4. Aggregate cancer risk for U.S. population. Using the exposure 
assumptions described in this unit for cancer for diuron, EPA has 
concluded that exposure to diruon from food and water will result in a 
cancer risk estimate of 1.4 x 10-\6\ for the general U.S. 
population. This risk estimate is within the range of 1 in 1 million 
that EPA considers negligible risk for cancer. EPA has generally 
concluded that computed cancer risks as high as 3 in 1 million fall 
within this risk range.
    Using the exposure assumptions described in this unit for cancer 
for the degradate MCPDMU, EPA has concluded that exposure to MCPDMU 
from fish and water will result in a cancer risk estimate of 5.9 x 10\-
7\, which is not of concern.
    5. 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 diuron residues.

IV. Other Considerations

A. Analytical Enforcement Methodology

    Adequate enforcement methodology (gas chromatography) is available 
to enforce the tolerance expression. The principle of the determination 
is the hydrolysis of diuron and its metabolites by alkaline reflux to 
3,4-dichloroanaline (3,4-DCA), followed by a distillation of the 
aniline into an acid solution. The acid distillate is made alkaline 
with concentrated base and subsequently extracted into an organic 
solvent (hexane) and analyzed by gas chromatography. With the modified 
method, recoveries exceeded 70% and the limit of quantitation (LOQ) is 
0.01. 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 Codex, Canadian, or Mexican tolerances or maximum 
residue limits for diuron in cactus; spearmint, tops; peppermint, tops; 
and fish - freshwater finfish, farm raised. Therefore, harmonization 
with international tolerances is not an issue for this action.

C. Response to Comments

    Several comments were received from a private citizen objecting to 
establishment of tolerances. The Agency has received similar comments 
from this commenter on numerous previous occasions. Refer to Federal 
Register of June 30, 2005 (70 FR 37686; FRL-7718-3); January 7, 2005 
(70 FR 1354; FRL-7691-4); and October 29, 2004 (69 FR 63096; FRL-7681-
9) for the Agency's response to these objections. In addition, the 
commenter noted several adverse effects seen in animal toxicology 
studies with diruon and claims because of these effects no tolerance 
should be approved. EPA has found, however, that there is a reasonable 
certainty of no harm to humans after considering these toxicological 
studies and the exposure levels of humans to diruon.
    The EPA also received an additional comment in support of this 
action.

V. Conclusion

    Upon completing review of the current diuron database, the Agency 
concluded that the tolerance expression proposed in the Notice of 
Filing should be changed to include metabolites hydrolyzable to 3,4-
dichloroaniline (3,4-DCA). This determination is based on

[[Page 32540]]

the results of the reviewed plant and animal metabolism studies.
    Currently, there are existing tolerances for residues of diuron on 
peppermint, hay at 2 ppm. The petitioner proposed tolerances be 
established on mint at 1.5 ppm. The EPA has determined that the 
preferred commodity terms are spearmint, tops and peppermint, tops and 
based on the residue field trial data the appropriate tolerance level 
for spearmint and peppermint should be 1.5 ppm. The EPA has also 
determined the preferred commodity terms should be cactus and fish - 
freshwater finfish, farm raised.
    Therefore, these tolerances are established for combined residues 
of diuron (3-(3,4-dichlorophenyl)-1,1-dimethylurea and its metabolites 
convertible to 3,4-dichloroaniline on cactus at 0.05 ppm, spearmint, 
tops at 1.5 ppm, peppermint, tops at 1.5 ppm and fish - freshwater 
finfish, farm raised at 2.0 ppm.

VI. Statutory and Executive Order Reviews

    This final rule establishes a tolerance 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 rule has been 
exempted from review under Executive Order 12866, this rule is not 
subject to Executive Order 13211, 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 6, 
2000) do not apply to this rule. In addition, This 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: May 31, 2007.
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 180.106 is amended by redesignating the text in paragraph 
(a) as (a)(1); by adding paragraph (a)(2); and by adding text to 
paragraph (c) to read as follows:

Sec.  180.106  Diuron; tolerances for residues.

    (a) (1) * * *
    (2) Tolerances are established for the combined residues of the 
herbicide diuron (3-(3,4-dichlorophenyl)-1,1-dimethylurea and its 
metabolites convertible to 3,4-dichloroaniline, in or on the following 
raw agricultural commodities:

------------------------------------------------------------------------
                 Commodity                        Parts per million
------------------------------------------------------------------------
Fish - freshwater finfish, farm raised      2.0
Peppermint, tops                            1.5
Spearmint, tops                             1.5
------------------------------------------------------------------------

* * * * *
    (c) Tolerances with regional registrations. Tolerances with a 
regional registration as defined in Sec.  180.1(n) are established for 
the combined residues of the herbicide diuron (3-(3,4-dichlorophenyl)-
1,1-dimethylurea and its metabolites convertible to 3,4-
dichloroaniline) in or on the raw agricultural commodities:

------------------------------------------------------------------------
                 Commodity                        Parts per million
------------------------------------------------------------------------
 Cactus                                     0.05
------------------------------------------------------------------------

* * * * *

[FR Doc. E7-11205 Filed 6-12-07; 8:45 am]

BILLING CODE 6560-50-S