[Federal Register Volume 64, Number 146 (Friday, July 30, 1999)]
[Rules and Regulations]
[Pages 41297-41305]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-19591]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 180
[OPP-300881; FRL 6087-2]
RIN 2070-AB78
Diuron; Pesticide Tolerances for Emergency Exemptions
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: This regulation establishes a time-limited tolerance for
combined residues of diuron in or on catfish. This action is in
response to EPA's granting of an emergency exemption under section 18
of the Federal Insecticide, Fungicide, and Rodenticide Act authorizing
use of the pesticide in catfish ponds. This regulation establishes a
maximum permissible level for residues of diuron in this food commodity
pursuant to section 408(l)(6) of the Federal Food, Drug, and Cosmetic
Act, as amended by the Food Quality Protection Act of 1996. The
tolerance will expire and is revoked on June 30, 2001.
DATES: This regulation is effective July 30, 1999. Objections and
requests for hearings must be received by EPA on or before September
28, 1999.
ADDRESSES: Written objections and hearing requests, identified by the
docket control number [OPP-300881], must be submitted to: Hearing Clerk
(1900), Environmental Protection Agency, Rm. M3708, 401 M St., SW.,
Washington, DC 20460. Fees accompanying objections and hearing requests
shall be labeled ``Tolerance Petition Fees'' and forwarded to: EPA
Headquarters Accounting Operations Branch, OPP (Tolerance Fees), P.O.
Box 360277M, Pittsburgh, PA 15251. A copy of any objections and hearing
requests filed with the Hearing Clerk identified by the docket control
number, [OPP-300881], must also be submitted to: Public Information and
Records Integrity Branch, Information Resources and Services Division
(7502C), Office of Pesticide Programs, Environmental Protection Agency,
401 M St., SW., Washington, DC 20460. In person, bring a copy of
objections and hearing requests to Rm. 119, Crystal Mall #2, 1921
Jefferson Davis Hwy., Arlington, VA.
A copy of objections and hearing requests filed with the Hearing
Clerk may also be submitted electronically by sending electronic mail
(e-mail) to: opp-docket@epa.gov. Copies of electronic objections and
hearing requests must be submitted as an ASCII file avoiding the use of
special characters and any form of encryption. Copies of objections and
hearing requests will also be accepted on disks in WordPerfect 5.1/6.1
or ASCII file format. All copies of electronic objections and hearing
requests must be identified by the docket control number [OPP-300881].
No Confidential Business Information (CBI) should be submitted through
e-mail. Copies of electronic objections and hearing requests on this
rule may be filed online at many Federal Depository Libraries.
FOR FURTHER INFORMATION CONTACT: By mail: David Deegan, Registration
Division (7505C), Office of Pesticide Programs, Environmental
Protection Agency, 401 M St., SW., Washington, DC 20460. Office
location, telephone number, and e-mail address: Rm. 286, Crystal Mall
#2, 1921 Jefferson Davis Hwy., Arlington, VA, 703-308-9358; e-mail:
deegan.dave@epa.gov.
SUPPLEMENTARY INFORMATION: EPA, on its own initiative, pursuant to
sections 408(l)(6) of the Federal Food, Drug, and Cosmetic Act (FFDCA),
21 U.S.C. 346a, is establishing a tolerance for combined residues of
the herbicide diuron and its metabolites, convertible to 3,4-
dichloroaniline in or on catfish at 2.0 parts per million (ppm). This
tolerance will expire and is revoked on June 30, 2001. EPA will publish
a document in the Federal Register to remove the revoked tolerance from
the Code of Federal Regulations.
I. Background and Statutory Findings
The Food Quality Protection Act of 1996 (FQPA)(Public Law 104-170)
was signed into law August 3, 1996. FQPA amends both the Federal Food,
Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 301 et seq., and the Federal
Insecticide, Fungicide, and Rodenticide Act (FIFRA), 7 U.S.C. 136 et
seq. The FQPA amendments went into effect immediately. Among other
things, FQPA amends FFDCA to bring all EPA pesticide tolerance-setting
activities under a new section 408 with a new safety standard and new
procedures. These activities are described in this preamble and
discussed in greater detail in the final rule establishing the time-
limited tolerance associated with the emergency exemption for use of
propiconazole on sorghum (61 FR 58135, November 13, 1996) (FRL-5572-9).
New section 408(b)(2)(A)(i) of the FFDCA allows EPA to establish a
tolerance (the legal limit for a pesticide chemical residue in or on a
food) only if EPA determines that the tolerance is ``safe.'' Section
408(b)(2)(A)(ii) defines ``safe'' to mean that ``there is a reasonable
certainty that no harm will result from aggregate exposure to the
pesticide chemical residue, including all anticipated dietary exposures
and all other exposures for which there is reliable information.'' This
includes exposure through drinking water and in residential settings,
but does not include occupational exposure. Section 408(b)(2)(C)
requires EPA to give special 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. . . .''
Section 18 of FIFRA authorizes EPA to exempt any Federal or State
agency from any provision of FIFRA, if EPA determines that ``emergency
conditions exist which require such exemption.'' This provision was not
amended by FQPA. EPA has established regulations governing such
emergency exemptions in 40 CFR part 166.
Section 408(l)(6) of the FFDCA requires EPA to establish a time-
limited tolerance or exemption from the requirement for a tolerance for
pesticide chemical residues in food that will result from the use of a
pesticide under an emergency exemption granted by EPA under section 18
of FIFRA. Such tolerances can be established without providing notice
or period for public comment.
[[Page 41298]]
Because decisions on section 18-related tolerances must proceed
before EPA reaches closure on several policy issues relating to
interpretation and implementation of the FQPA, EPA does not intend for
its actions on such tolerances to set binding precedents for the
application of section 408 and the new safety standard to other
tolerances and exemptions.
II. Emergency Exemption for Diuron on Catfish and FFDCA Tolerances
EPA has authorized, under FIFRA section 18, the use of diuron in
and on catfish ponds for control of algae in Mississippi, Louisiana,
and Arkansas. After having reviewed the submissions, EPA concurs that
emergency conditions exist in these States. The three applicants
requested use of diuron in catfish ponds to control unwanted growth of
blue-green algae. The rapid spread of the blue-green algae makes it a
secondary food source--albeit undesirable--for the catfish. If algae is
present in the ponds, the catfish consume large quantities of it,
resulting in an undesirable flavor in the catfish fillet, when the fish
are harvested and eaten. Fish with this off flavor are less marketable
for producers.
As part of its assessment of this emergency exemption, EPA assessed
the potential risks presented by residues of diuron in or on catfish.
In doing so, EPA considered the safety standard in FFDCA section
408(b)(2), and EPA decided that the necessary tolerance under FFDCA
section 408(l)(6) would be consistent with the safety standard and with
FIFRA section 18. Consistent with the need to move quickly on the
emergency exemption in order to address an urgent non-routine situation
and to ensure that the resulting food is safe and lawful, EPA is
issuing this tolerance without notice and opportunity for public
comment under section 408(e), as provided in section 408(l)(6).
Although this tolerance will expire and is revoked on June 30, 2001,
under FFDCA section 408(l)(5), residues of the pesticide not in excess
of the amounts specified in the tolerance remaining in or on catfish
after that date will not be unlawful, provided the pesticide is applied
in a manner that was lawful under FIFRA, and the residues do not exceed
a level that was authorized by this tolerance at the time of that
application. EPA will take action to revoke this tolerance earlier if
any experience with, scientific data on, or other relevant information
on this pesticide indicate that the residues are not safe.
Because this tolerance is being approved under emergency
conditions, EPA has not made any decisions about whether diuron meets
EPA's registration requirements for use on catfish or whether a
permanent tolerance for this use would be appropriate. Under these
circumstances, EPA does not believe that this tolerance serves as a
basis for registration of diuron by a State for special local needs
under FIFRA section 24(c). Nor does this tolerance serve as the basis
for any State other than Mississippi, Louisiana, and Arkansas to use
this pesticide on this crop under section 18 of FIFRA without following
all provisions of EPA's regulations implementing section 18 as
identified in 40 CFR part 166. For additional information regarding the
emergency exemption for diuron, contact the Agency's Registration
Division at the address provided under the ``ADDRESSES'' section.
III. Aggregate Risk Assessment and Determination of Safety
EPA performs a number of analyses to determine the risks from
aggregate exposure to pesticide residues. For further discussion of the
regulatory requirements of section 408 and a complete description of
the risk assessment process, see the final rule on Bifenthrin Pesticide
Tolerances (62 FR 62961, November 26, 1997) (FRL-5754-7).
Consistent with section 408(b)(2)(D), EPA has reviewed the
available scientific data and other relevant information in support of
this action. EPA has sufficient data to assess the hazards of diuron
and to make a determination on aggregate exposure, consistent with
section 408(b)(2), for a time-limited tolerance for combined residues
of diuron on catfish at 2.0 ppm. EPA's assessment of the dietary
exposures and risks associated with establishing the tolerance follows.
A. Toxicological Profile
EPA has evaluated the available toxicity data and considered its
validity, completeness, and reliability as well as the relationship of
the results of the studies to human risk. EPA has also considered
available information concerning the variability of the sensitivities
of major identifiable subgroups of consumers, including infants and
children. The nature of the toxic effects caused by diuron are
discussed in this unit.
B. Toxicological Endpoint
1. Acute toxicity. Acute reference dose (RfD) 0.16 milligram/
kilogram/day (mg/kg/day). For acute dietary risk assessment, EPA has
identified the no observed adverse effect level (NOAEL) of 16.0 mg/kg/
day, based on decreased body weight (beginning at gestation day 9) and
food consumption (during gestation days 6-10) at the lowest observed
adverse effect level (LOAEL) of 80 mg/kg/day, from the developmental
study in the rat. EPA's risk assessment has evaluated acute dietary
risk to all population subgroups.
2. Chronic toxicity. EPA has established the RfD for diuron at
0.003 mg/kg/day. This RfD is based on a 2-year chronic feeding/
oncogenicity study in the rat with a LOAEL of 1.02 mg/kg/day and an
uncertainty factor (UF) of 300 (additional UF of 3 for the use of a
LOAEL) based on decreased erythrocyte count in females, increased
hemosiderin in the spleen, increased spleen weight, bone marrow
activation, increased hematopoietic marrow, decreased fat marrow (%
surface area of fat marrow in bone marrow) and thickened urinary
bladder wall in males.
3. Carcinogenicity. Diuron has been classified as a ``known/
likely'' human carcinogen by all routes, based on urinary bladder
carcinomas in both sexes of the Wistar rat, kidney carcinomas in the
male rat (a rare tumor), and mammary gland carcinomas in the female
NMRI mouse. A Q1*(mg/kg/day)-1 of 1.91 x
10-2 in human equivalents has been calculated based on the
male rat urinary bladder carcinomas.
C. Exposures and Risks
1. From food and feed uses. Tolerances have been established (40
CFR 180.106) for the combined residues of diuron (3-(3,4-
dichlorophenyl)-1,1-dimethylurea), in or on a variety of raw
agricultural commodities at levels ranging from 0.1 ppm in nuts and
peaches to 7 ppm in bermuda grass. The residues of concern for diuron
in plant commodities are the parent compound and all metabolites
convertible to 3,4-dichloroaniline (DCA). Although the Code of Federal
Regulations (CFR) only mentions diuron in the tolerance expression, the
analytical methods determine all metabolites convertible to 3,4-
dichloroaniline. The parent compound usually comprises only a small
portion of the total residue or of the DCA-containing residues. For
both the acute and chronic dietary risk assessments it was assumed that
total residues of the closely related herbicides, linuron and propanil
will contribute to the toxicological effects of concern (with the acute
dietary analysis, there were two exceptions: residues of linuron on
potatoes and soybeans where metabolism studies were examined to
determine which metabolites are common to those from diuron). It was
[[Page 41299]]
also assumed that the tolerances for linuron and propanil represent
total residues convertible to 3,4-dichloroaniline, although petition
files and residue data were not examined for linuron to confirm this.
The propanil residue studies which were reviewed for chronic
anticipated residues did involve determination of total base-released
3,4-dichloroaniline. Risk assessments were conducted by EPA to assess
dietary exposures and risks from diuron as follows:
i. Acute exposure and risk. Acute dietary 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. For this risk assessment of the section
18 requests to use diuron, EPA has identified an acute RfD of 0.16 mg/
kg/day. In conducting this acute dietary risk analysis, EPA used
partially refined, i.e., percent crop treated data. In those cases
where data indicated <1% crop="" treated,="" a="" value="" of="" 1%="" was="" used="" for="" the="" analysis.="" for="" those="" crops="" where="" information="" was="" not="" available="" to="" epa,="" a="" default="" value="" of="" 100%="" crop="" treated="" was="" used="" for="" this="" risk="" assessment,="" epa="" assumed="" that="" 100%="" of="" catfish="" would="" contain="" residues="" of="" diuron.="" at="" the="" time="" the="" anticipated="" residues="" (ars)="" were="" developed="" for="" the="" acute="" dietary="" risk="" assessment,="" percent="" crop="" treated="" data="" were="" not="" available="" for="" linuron="" and="" propanil;="" therefore,="" it="" was="" assumed="" that="" 100%="" of="" the="" crop="" was="" treated="" for="" commodities="" having="" tolerances="" for="" those="" herbicides.="" the="" novigen="" deem="" (dietary="" exposure="" evaluation="" model)="" system="" was="" used="" for="" the="" acute="" dietary="" exposure="" analysis,="" utilizing="" mixtures="" of="" tolerances/anticipated="" residues="" and="" percent="" crop="" treated="" data="" for="" diuron,="" linuron="" and="" propanil.="" with="" respect="" to="" fruit="" juices,="" the="" default="" concentration="" factors="" in="" the="" deem="" run="" were="" used="" except="" for="" grape="" juice="" and="" pineapple="" juice.="" the="" population="" subgroup="" with="" the="" highest="" acute="" dietary="" exposure="" (food="" only)="" is="" non-nursing="" infants.="" with="" a="" high-end="" anticipated="" residue="" contribution="" (arc)="" exposure="" estimate="" of="" 0.03810="" mg/kg/day,="" it="" was="" estimated="" that="" only="" 24%="" of="" the="" acute="" rfd="" population="" adjusted="" dose="" (pad)="" would="" be="" utilized="" for="" this="" population="" subgroup.="" this="" acute="" dietary="" risk="" estimate="" (food="" only)="" should="" be="" viewed="" as="" a="" partially="" refined="" risk="" estimate="" (the="" diuron="" assessment="" was="" highly="" refined);="" further="" refinement="" using="" additional="" anticipated="" residue="" values="" and="" percent="" crop="" treated="" data="" for="" linuron="" and="" propanil="" in="" conjunction="" with="" another="" monte="" carlo="" analysis="" would="" result="" in="" a="" lower="" acute="" dietary="" exposure="" estimate.="" to="" arrive="" at="" this="" conclusion,="" epa="" determined="" that="" for="" this="" tolerance="" action="" only,="" the="" fqpa="" safety="" factor="" be="" removed="" (1x)="" in="" assessing="" the="" risk="" posed="" by="" diuron="" (see="" aggregate="" risk="" section="" for="" infants="" and="" children).="" therefore,="" the="" acute="" rfd="" is="" identical="" to="" the="" acute="" pad.="" ii.="" chronic="" exposure="" and="" risk.="" for="" this="" risk="" assessment,="" epa="" has="" identified="" a="" chronic="" rfd="" of="" 0.003="" mg/kg/day.="" for="" this="" risk="" assessment,="" epa="" has="" utilized="" the="" novigen="" deem="" system="" for="" the="" chronic="" dietary="" exposure="" analysis.="" in="" conducting="" the="" chronic="" dietary="" risk="" analysis,="" epa="" used="" highly="" refined="" data.="" as="" stated="" previously,="" epa="" included="" percent="" crop="" treated="" data="" for="" diuron="" (see="" acute="" risk="" section,="" above).="" percent="" crop="" treated="" data="" for="" linuron="" uses="" were="" taken="" from="" the="" dietary="" risk="" evaluation="" system="" (dres)="" run="" conducted="" in="" 1995="" and="" propanil="" uses="" (1995-="" 98)="" were="" also="" utilized="" by="" epa="" in="" this="" risk="" assessment.="" for="" those="" crops="" where="" epa="" did="" not="" have="" information,="" a="" default="" value="" of="" 100%="" crop="" treated="" was="" used.="" anticipated="" residues="" of="" diuron="" have="" been="" developed="" previously="" for="" numerous="" commodities.="" these="" anticipated="" residues="" were="" used="" with="" the="" following="" additions:="" 0.03="" ppm="" for="" alfalfa="" sprouts="" (1%="" crop="" treated)="" and="" 0.92="" ppm="" for="" fish-finfish/freshwater="" (76%="" crop="" treated).="" for="" the="" purposes="" of="" the="" present="" section="" 18="" use,="" an="" updated="" analysis="" of="" linuron="" residues="" in="" food="" was="" not="" conducted;="" therefore,="" the="" most="" recent="" percent="" crop="" treated="" data="" for="" linuron="" (1995-97)="" was="" not="" used.="" chronic="" exposures="" from="" linuron="" for="" various="" populations="" were="" taken="" from="" the="" dres="" analysis="" conducted="" in="" 1995="" in="" support="" of="" the="" increase="" in="" the="" asparagus="" tolerance.="" that="" analysis="" used="" anticipated="" residues="" (mean="" field="" trial="" values)="" and="" percent="" crop="" treated="" available="" at="" that="" time="" for="" numerous="" crops.="" for="" propanil,="" the="" chronic="" anticipated="" residues="" and="" percent="" crop="" treated="" have="" also="" been="" calculated="" by="" epa.="" the="" chronic="" dietary="" risk="" analysis="" includes="" monitoring="" data="" for="" residues="" in="" drinking="" water.="" therefore,="" in="" this="" document="" epa="" summarizes="" risk="" of="" exposure="" for="" both="" food="" and="" water="" in="" the="" aggregate="" risk="" section.="" section="" 408(b)(2)(e)="" authorizes="" epa="" to="" use="" available="" data="" and="" information="" on="" the="" anticipated="" residue="" levels="" of="" pesticide="" residues="" in="" food="" and="" the="" actual="" levels="" of="" pesticide="" chemicals="" that="" have="" been="" measured="" in="" food.="" if="" epa="" relies="" on="" such="" information,="" epa="" must="" 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.="" following="" the="" initial="" data="" submission,="" epa="" is="" authorized="" to="" require="" similar="" data="" on="" a="" time="" frame="" it="" deems="" appropriate.="" as="" required="" by="" section="" 408(b)(2)(e),="" epa="" will="" issue="" a="" data="" call-in="" for="" information="" relating="" to="" anticipated="" residues="" to="" be="" submitted="" no="" later="" than="" 5="" years="" from="" the="" date="" of="" issuance="" of="" this="" tolerance.="" section="" 408(b)(2)(f)="" states="" that="" the="" agency="" may="" use="" data="" on="" the="" actual="" percent="" of="" crop="" treated="" (pct)="" for="" assessing="" chronic="" dietary="" risk="" only="" if="" the="" agency="" can="" make="" the="" following="" findings:="" that="" 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;="" that="" the="" exposure="" estimate="" does="" not="" underestimate="" exposure="" for="" any="" significant="" subpopulation="" group;="" and="" if="" 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="" the="" section="" 408(b)(2)(f),="" epa="" may="" require="" registrants="" to="" submit="" data="" on="" pct.="" the="" agency="" used="" pct="" information="" as="" follows:="" as="" detailed="" above,="" in="" conducting="" both="" the="" acute="" and="" chronic="" dietary="" risk="" analyses,="" epa="" used="" pct="" data.="" in="" order="" to="" conduct="" such="" a="" refined="" analysis,="" epa="" utilized="" the="" novigen="" deem="" system="" for="" the="" dietary="" exposure="" analysis,="" with="" which="" epa="" calculated="" mixtures="" of="" tolerances/="" anticipated="" residues="" and="" percent="" crop="" treated="" data="" for="" diuron,="" linuron="" uses="" taken="" from="" the="" dres="" run="" conducted="" in="" 1995,="" and="" propanil="" uses="" (1995-98).="" with="" respect="" to="" fruit="" juices,="" the="" default="" concentration="" factors="" in="" the="" deem="" run="" were="" used="" except="" for="" grape="" juice="" and="" pineapple="" juice.="" processing="" studies="" indicated="" that="" residues="" did="" not="" concentrate="" in="" the="" latter="" two="" juices.="" in="" those="" cases="" where="" data="" indicated=""><1% crop="" treated,="" a="" value="" of="" 1%="" was="" used="" for="" the="" analysis.="" for="" those="" crops="" where="" information="" was="" not="" available="" to="" epa,="" a="" default="" value="" of="" 100%="" crop="" treated="" was="" used.="" at="" the="" time="" the="" anticipated="" residues="" were="" developed="" for="" the="" acute="" dietary="" risk="" assessment,="" percent="" crop="" treated="" data="" were="" not="" available="" for="" linuron="" and="" propanil;="" therefore,="" it="" was="" assumed="" that="" 100%="" of="" the="" crop="" was="" treated="" for="" commodities="" having="" tolerances="" for="" those="" herbicides.="" anticipated="" residues="" of="" diuron="" have="" been="" developed="" previously="" for="" numerous="" commodities.="" these="" anticipated="" residues="" were="" used="" with="" the="" following="" additions:="" 0.03="" ppm="" for="" alfalfa="" sprouts="" (1%="" crop="" treated)="" and="" 0.92="" ppm="" for="" fish-finfish/freshwater="" (76%="" crop="" [[page="" 41300]]="" treated).="" for="" the="" purposes="" of="" the="" present="" action,="" an="" updated="" analysis="" of="" linuron="" residues="" in="" food="" was="" not="" conducted;="" therefore,="" the="" most="" recent="" percent="" crop="" treated="" data="" for="" linuron="" (1995-97)="" was="" not="" used.="" chronic="" exposures="" from="" linuron="" for="" various="" populations="" were="" taken="" from="" epa's="" dietary="" risk="" evaluation="" system="" (dres)="" analysis="" conducted="" in="" 1995="" in="" support="" of="" the="" increase="" in="" the="" asparagus="" tolerance.="" that="" analysis="" used="" anticipated="" residues="" (mean="" field="" trial="" values)="" and="" percent="" crop="" treated="" available="" at="" that="" time="" for="" numerous="" crops.="" for="" propanil,="" the="" chronic="" anticipated="" residues="" and="" percent="" crop="" treated="" have="" also="" been="" calculated="" by="" epa.="" the="" chronic="" dietary="" risk="" analysis="" includes="" monitoring="" data="" for="" residues="" in="" drinking="" water.="" the="" agency="" believes="" that="" the="" three="" conditions,="" discussed="" in="" section="" 408(2)(f)="" in="" this="" unit="" concerning="" the="" agency's="" responsibilities="" in="" assessing="" chronic="" dietary="" risk="" findings,="" have="" been="" met.="" the="" pct="" estimates="" are="" derived="" from="" federal="" and="" private="" market="" survey="" data,="" which="" are="" reliable="" and="" have="" a="" valid="" basis.="" typically,="" a="" range="" of="" estimates="" are="" supplied="" and="" the="" upper="" end="" of="" this="" range="" is="" assumed="" for="" the="" exposure="" assessment.="" by="" using="" this="" upper="" end="" estimate="" of="" the="" pct,="" the="" agency="" is="" reasonably="" certain="" that="" the="" percentage="" of="" the="" food="" treated="" is="" not="" likely="" to="" be="" underestimated.="" the="" 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.="" from="" drinking="" water.="" epa="" conducted="" an="" analysis="" of="" the="" contribution="" of="" residues="" of="" diuron="" from="" drinking="" water="" based="" upon="" monitoring="" data="" for="" water="" with="" emphasis="" on="" the="" us="" geological="" survey="" (usgs)="" national="" water="" quality="" assessment="" program="" (nawqa)="" surface="" water="" sampling="" in="" central="" california.="" the="" nawqa="" program="" analyzed="" 3,417="" samples="" of="" surface="" water="" for="" diuron="" throughout="" the="" united="" states.="" approximately="" 13%="" of="" the="" samples="" (429)="" contained="" detectable="" diuron="" residues="" (only="" parent="" compound="" analyzed)="" ranging="" from="" 0.001="" to="" 14="" parts="" per="" billion="" (ppb).="" the="" average="" value="" for="" the="" detectable="" samples="" was="" 0.8="" ppb.="" the="" 95th="" percentile="" value="" for="" the="" surface="" water="" samples="" was="" 0.2="" ppb.="" for="" ground="" water="" there="" were="" 2,726="" samples="" analyzed="" and="" about="" 2%="" (51)="" contained="" diuron="" residues="" with="" values="" ranging="" from="" 0.002="" to="" 2="" ppb.="" however,="" epa's="" analysis="" has="" concluded="" that="" the="" above="" data="" may="" underestimate="" or="" under="" represent="" concentrations="" of="" diuron="" to="" be="" expected="" in="" surface="" water,="" due="" to="" low="" recovery="" rates="" and="" incomplete="" sampling="" in="" some="" areas.="" furthermore,="" estimates="" for="" diuron="" degradates="" in="" drinking="" water="" could="" not="" be="" provided="" due="" to="" the="" small="" amount="" of="" data="" and="" the="" data="" not="" being="" representative="" of="" drinking="" water.="" in="" light="" of="" these="" factors,="" epa="" has="" concluded="" that="" the="" highest="" value="" of="" 14="" ppb="" of="" all="" surface="" water="" samples="" having="" detectable="" residues="" should="" be="" used="" for="" acute="" risk="" assessment="" and="" that="" the="" average="" value="" of="" 0.8="" ppb="" of="" all="" the="" surface="" water="" samples="" having="" detectable="" residues="" should="" be="" used="" for="" chronic="" risk="" assessment.="" by="" using="" these="" upper="" end="" values="" of="" diuron="" parent="" in="" surface="" water="" as="" the="" estimates,="" at="" least="" some="" compensation="" can="" be="" made="" for="" the="" poor="" recoveries="" of="" the="" analytical="" method="" and="" the="" lack="" of="" sufficient="" data="" to="" predict="" levels="" of="" diuron="" degradates,="" many="" of="" which="" are="" likely="" to="" be="" formed="" by="" linuron="" and="" propanil="" as="" well.="" for="" the="" acute="" dietary="" aggregate="" risk="" analysis,="" 14="" ppb="" was="" used="" as="" a="" value="" for="" comparison="" in="" calculating="" a="" drinking="" water="" level="" of="" comparison="" (dwloc).="" when="" the="" acute="" deem="" run="" was="" conducted,="" it="" was="" determined="" at="" that="" point="" that="" the="" percentage="" of="" the="" acute="" rfd="" (pad)="" taken="" up="" by="" residue="" exposure="" in="" food="" only="" was="" sufficiently="" low="" such="" that="" a="" dwloc="" could="" be="" calculated="" in="" lieu="" of="" conducting="" a="" probabilistic="" analysis="" with="" inclusion="" of="" water.="" however,="" for="" the="" chronic="" dietary="" aggregate="" risk="" analysis,="" 0.8="" ppb="" was="" incorporated="" into="" the="" deem="" assessment="" as="" a="" value="" taken="" from="" monitoring="" data.="" the="" above="" risk="" assessment="" is="" sufficient="" for="" the="" purposes="" of="" the="" related="" section="" 18="" emergency="" exemption="" authorized="" by="" the="" agency.="" however,="" epa="" expects="" that="" for="" it="" to="" take="" action="" on="" a="" registration="" and="" establishment="" of="" a="" permanent="" tolerance="" for="" the="" catfish="" pond="" use,="" a="" more="" thorough="" analysis="" would="" be="" undertaken="" to="" determine="" which="" degradates="" of="" diuron,="" linuron="" and="" propanil="" would="" be="" included="" in="" drinking="" water="" residue="" estimates.="" 3.="" from="" non-dietary="" exposure.="" diuron="" is="" currently="" not="" registered="" for="" use="" on="" any="" residential="" sites.="" 4.="" cumulative="" exposure="" to="" substances="" with="" a="" common="" mechanism="" of="" toxicity.="" diuron="" is="" a="" member="" of="" the="" phenylurea="" class="" of="" pesticides.="" other="" members="" of="" this="" class="" include="" fluometuron,="" fenuron-tca,="" linuron,="" siduron="" and="" tebuthiuron.="" section="" 408(b)(2)(d)(v)="" requires="" that,="" when="" considering="" whether="" to="" establish,="" modify,="" or="" revoke="" a="" tolerance,="" the="" agency="" consider="" ``available="" information''="" concerning="" the="" cumulative="" effects="" of="" a="" particular="" pesticide's="" residues="" and="" ``other="" substances="" that="" have="" a="" common="" mechanism="" of="" toxicity.''="" the="" agency="" believes="" that="" ``available="" information''="" in="" this="" context="" might="" include="" not="" only="" toxicity,="" chemistry,="" and="" exposure="" data,="" but="" also="" scientific="" policies="" and="" methodologies="" for="" understanding="" common="" mechanisms="" of="" toxicity="" and="" conducting="" cumulative="" risk="" assessments.="" for="" most="" pesticides,="" although="" the="" agency="" has="" some="" information="" in="" its="" files="" that="" may="" turn="" out="" to="" be="" helpful="" in="" eventually="" determining="" whether="" a="" pesticide="" shares="" a="" common="" mechanism="" of="" toxicity="" with="" any="" other="" substances,="" epa="" does="" not="" at="" this="" time="" have="" the="" methodologies="" to="" resolve="" the="" complex="" scientific="" issues="" concerning="" common="" mechanism="" of="" toxicity="" in="" a="" meaningful="" way.="" epa="" has="" begun="" a="" pilot="" process="" to="" study="" this="" issue="" further="" through="" the="" examination="" of="" particular="" classes="" of="" pesticides.="" the="" agency="" hopes="" that="" the="" results="" of="" this="" pilot="" process="" will="" increase="" the="" agency's="" scientific="" understanding="" of="" this="" question="" such="" that="" epa="" will="" be="" able="" to="" develop="" and="" apply="" scientific="" principles="" for="" better="" determining="" which="" chemicals="" have="" a="" common="" mechanism="" of="" toxicity="" and="" evaluating="" the="" cumulative="" effects="" of="" such="" chemicals.="" the="" agency="" anticipates,="" however,="" that="" even="" as="" its="" understanding="" of="" the="" science="" of="" common="" mechanisms="" increases,="" decisions="" on="" specific="" classes="" of="" chemicals="" will="" be="" heavily="" dependent="" on="" chemical-specific="" data,="" much="" of="" which="" may="" not="" be="" presently="" available.="" although="" at="" present="" the="" agency="" does="" not="" know="" how="" to="" apply="" the="" information="" in="" its="" files="" concerning="" common="" mechanism="" issues="" to="" most="" risk="" assessments,="" there="" are="" pesticides="" as="" to="" which="" the="" common="" mechanism="" issues="" can="" be="" resolved.="" these="" pesticides="" include="" those="" that="" are="" toxicologically="" dissimilar="" to="" existing="" chemical="" substances="" (in="" which="" case="" the="" agency="" can="" conclude="" that="" it="" is="" unlikely="" that="" a="" pesticide="" shares="" a="" common="" mechanism="" of="" activity="" with="" other="" substances)="" and="" pesticides="" that="" produce="" a="" common="" toxic="" metabolite="" (in="" which="" case="" common="" mechanism="" of="" activity="" will="" be="" assumed).="" [[page="" 41301]]="" diuron="" shares="" a="" common="" metabolite="" with="" linuron="" and="" propanil.="" the="" non-cancer="" dietary="" risk="" assessments="" take="" this="" into="" consideration.="" for="" the="" purposes="" of="" this="" section="" 18,="" residues="" from="" linuron="" and="" propanil="" were="" not="" taken="" into="" consideration="" for="" the="" carcinogenicity="" risk="" assessment="" because="" the="" target="" organs="" (i.e.,="" the="" tumors)="" for="" diuron="" versus="" linuron="" and="" propanil="" are="" of="" different="" origins="" and="" because="" metabolism="" and="" mechanistic="" data="" indicate="" that="" the="" mechanism="" of="" action="" for="" tumor="" induction="" are="" different="" for="" diuron="" when="" compared="" to="" linuron="" and="" propanil.="" the="" residues="" of="" concern="" for="" diuron="" are="" the="" parent="" compound="" and="" all="" metabolites="" convertible="" to="" 3,4-dichloroaniline="" (dca).="" there="" are="" two="" closely="" related="" herbicides="" which="" are="" also="" metabolized="" to="" dca="" and/or="" other="" residues="" convertible="" to="" dca="" (linuron="" and="" propanil).="" therefore,="" it="" was="" assumed="" that="" residues="" from="" the="" use="" of="" these="" two="" pesticides="" will="" contribute="" to="" the="" toxicological="" effects="" of="" concern="" for="" the="" dietary="" risk="" analyses="" (for="" further="" explantion,="" see="" exposure="" discussion="" in="" section="" iii.="" c.="" below).="" the="" toxicological="" data="" bases="" for="" these="" two="" pesticides="" were="" examined="" to="" see="" if="" there="" are="" similar="" target="" organs.="" for="" the="" acute="" dietary="" risk="" analysis,="" the="" toxicological="" endpoint,="" decreased="" bodyweight="" and="" food="" consumption,="" is="" not="" specific="" enough="" for="" comparison.="" nevertheless,="" it="" was="" still="" assumed="" that="" residues="" from="" all="" three="" herbicides="" will="" contribute="" to="" the="" same="" acute="" effects.="" for="" chronic="" exposure,="" these="" three="" pesticides="" share="" a="" similar="" toxicological="" endpoint:="" hematological="" effects,="" particularly="" methemoglobinemia.="" these="" effects="" were="" observed="" in="" chronic="" feeding="" studies,="" in="" either="" the="" rat,="" dog="" or="" mouse.="" the="" target="" organs="" for="" carcinogenicity="" may="" be="" similar="" for="" linuron="" and="" propanil,="" but="" not="" for="" diuron.="" diuron="" induces="" urinary="" bladder="" carcinomas="" in="" rats="" (both="" sexes)="" and="" mammary="" gland="" carcinomas="" in="" female="" mice.="" in="" addition,="" an="" increase="" in="" the="" incidence="" of="" a="" rare="" kidney="" tumor="" was="" observed="" in="" male="" rats.="" linuron="" induces="" testicular="" interstitial="" cell="" adenomas="" in="" rats="" and="" hepatocellular="" adenomas="" in="" mice.="" available="" mechanistic="" and="" metabolism="" data="" indicate="" that="" linuron="" and="" diuron="" may="" be="" inducing="" tumors="" through="" different="" mechanisms="" of="" action.="" propanil="" has="" not="" been="" reviewed="" by="" the="" office="" of="" pesticide="" programs="" cancer="" assessment="" review="" committee="" (carc).="" however,="" two="" new="" studies="" have="" been="" received="" which="" indicate="" that="" it="" may="" induce="" malignant="" lymphomas="" of="" the="" spleen="" in="" female="" mice,="" testicular="" interstitial="" cell="" tumors="" in="" male="" rats="" and="" hepatocellular="" adenomas="" in="" female="" rats,="" the="" latter="" at="" a="" dose="" level="" which="" probably="" exceeds="" the="" maximum="" tolerated="" dose.="" therefore,="" since="" the="" target="" organs="" for="" tumor="" induction="" for="" diuron="" are="" different="" than="" those="" for="" linuron="" and="" propanil,="" and="" data="" are="" available="" which="" indicate="" that="" the="" mechanism="" of="" action="" may="" be="" different="" for="" diuron,="" for="" the="" purpose="" of="" this="" tolerance="" action,="" the="" estimated="" dietary="" carcinogenic="" risk="" will="" not="" include="" residues="" from="" linuron="" and="" propanil.="" however,="" for="" any="" future="" permanent="" tolerance="" requests,="" a="" detailed="" analysis="" of="" any="" potential="" contribution="" of="" residues="" from="" linuron="" and="" propanil="" to="" the="" dietary="" carcinogenic="" risk="" will="" be="" conducted,="" including="" examination="" of="" available="" toxicological="" and="" mechanistic="" data.="" epa="" does="" not="" have,="" at="" this="" time,="" available="" data="" to="" determine="" whether="" diuron="" has="" a="" common="" mechanism="" of="" toxicity="" with="" any="" other="" substances="" or="" how="" to="" include="" this="" pesticide="" in="" a="" cumulative="" risk="" assessment.="" for="" the="" purposes="" of="" this="" tolerance="" action,="" therefore,="" epa="" has="" not="" assumed="" that="" diuron="" has="" a="" common="" mechanism="" of="" toxicity="" with="" substances="" other="" than="" linuron="" and="" propanil.="" for="" more="" 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="" final="" rule="" for="" bifenthrin="" pesticide="" tolerances="" (62="" fr="" 62961,="" november="" 26,="" 1997).="" d.="" aggregate="" risks="" and="" determination="" of="" safety="" for="" u.s.="" population="" 1.="" acute="" risk.="" the="" acute="" dietary="" risk="" analysis="" estimated="" that="" the="" acute="" dietary="" exposure="" (food="" only)="" for="" the="" u.s.="" population="" will="" utilize="" 17%="" of="" the="" acute="" rfd,="" which,="" because="" there="" is="" no="" fqpa="" 10x="" safety="" factor="" added="" to="" this="" risk="" assessment,="" is="" identical="" to="" the="" acute="" population="" adjusted="" dose="" (pad).="" all="" other="" adult="" population="" subgroups="" have="" acute="" risk="" estimates="" (food="" only)="" below="" that="" of="" the="" u.s.="" population.="" as="" stated="" previously,="" the="" acute="" dietary="" risk="" analysis="" used="" partially="" refined="" arc="" exposure="" estimates="" and="" percent="" crop="" treated="" values.="" the="" analysis="" included="" total="" residues="" convertible="" to="" the="" diuron="" metabolite,="" dca="" from="" food.="" residue="" contributions="" from="" diuron,="" linuron="" and="" propanil="" uses="" were="" taken="" into="" account.="" for="" dca-convertible="" residues="" from="" diuron,="" linuron="" and="" propanil,="" it="" was="" determined="" that="" an="" acute="" dietary="" exposure="" (food="" plus="" water)="" of="" 100%="" or="" less="" of="" the="" acute="" rfd="" (pad)="" is="" acceptable="" to="" protect="" the="" safety="" of="" all="" population="" subgroups.="" the="" estimated="" exposures="" at="" the="" 99.9th="" percentile="" for="" all="" population="" subgroups="" utilize="" less="" than="" 100%="" of="" the="" acute="" rfd="" (pad).="" monitoring="" data="" were="" available="" for="" drinking="" water="" for="" the="" acute="" aggregate="" risk="" estimate.="" however,="" since="" the="" percentage="" of="" the="" acute="" rfd="" (pad)="" taken="" up="" by="" exposure="" to="" dca="" residues="" from="" food="" only="" was="" sufficiently="" low,="" it="" was="" decided="" that="" a="" dwloc="" would="" be="" calculated.="" therefore,="" for="" this="" tolerance,="" the="" estimated="" maximum="" concentration="" of="" 14="" ppb="" from="" the="" monitoring="" data="" was="" used="" for="" comparison="" to="" the="" back="" calculated="" human="" health="" dwloc="" for="" the="" acute="" endpoint.="" the="" dwlocs="" for="" the="" specific="" population="" subgroups="" are="" calculated="" as="" follows:="" the="" maximum="" water="" exposure="" (acute)="" (mg/kg/day)="acute" pad="" -="" food="" exposure="" (mg/kg/day)="" from="" acute="" deem="" run.="" the="" dwloc="">g/L) = max. water exposure (mg/kg/day) x body
wt (kg) (10-3 mg/g) x water consumption
(L/day).
EPA used the following default body weights in these calculations:
General U.S. population, 70 kg; males (13+ years old), 70 kg; females
(13+ years old), 60 kg; and other adult populations, 70 kg.
EPA's default daily drinking rates are 2L/day for adults.
The DWLOCs are between 4,300 and 5,000 ppb for acute dietary risk.
Based on a comparison of the calculated DWLOCs and the estimated
exposure to diuron in drinking water (14 ppb), EPA does not expect the
aggregate exposure to exceed 100% of the Acute RfD for any of the U.S.
population. The DWLOCs are at least 100 times higher than the maximum
value observed in monitoring studies. Therefore, EPA concludes that
there is a reasonable certainty that no harm will result to the U.S.
population from acute aggregate exposure to diuron residues.
2. Chronic risk. EPA determined that for this tolerance, the FQPA
Safety Factor can be removed (1x) in assessing the risk posed by
diuron. Therefore, because there is not a FQPA 10x Safety Factor added
to this risk assessment, the chronic RfD is identical to the chronic
PAD. EPA has calculated that chronic dietary exposure to diuron alone
from food and water will utilize 4.7% of the chronic RfD (PAD) for the
U.S. population. When residues from linuron and propanil are included,
the dietary exposure to residues convertible to the metabolite (DCA)
from food and water will utilize 12% of the chronic RfD (PAD) for the
U.S. population and 15% of the chronic RfD (PAD) for the non-hispanic,
non-white, non-black U.S. population.
As stated previously, the chronic dietary risk analysis used highly
refined
[[Page 41302]]
ARC exposure estimates and percent crop treated values. EPA generally
has no concern for exposures below 100% of the chronic RfD (PAD)
because the chronic RfD (PAD) represents the level at or below which
daily aggregate dietary exposure over a lifetime will not pose
appreciable risks to human health. There are no registered residential
uses for diuron. Therefore, EPA concludes that there is a reasonable
certainty that no harm to adults will result from chronic aggregate
exposure to DCA-convertible residues from diuron, linuron and propanil.
3. Short- and intermediate-term risk. Short- and intermediate-term
aggregate exposure takes into account chronic dietary food and water
(considered to be a background exposure level) plus non-dietary, non-
occupational exposures. Since there are no registered uses of diuron
that would result in such exposures, short- and intermediate-term
aggregate risk estimates were not conducted.
4. Aggregate cancer risk for U.S. population. The dietary cancer
risk for the U.S. population is calculated by multiplying the
Q1* by the dietary exposure value. The Q1*(mg/kg/
day)-1 for diuron is 1.91 x 10-2. The dietary
exposure value for registered food crops for the U.S. population is
0.000092 mg/kg/day. This highly refined value does not include either
the drinking water exposure value or the catfish exposure that was
included in the exposure values described above in the discussion on
chronic aggregate risk. Multiplying the Q1* by the dietary
exposure value for the U.S. population, the cancer risk for the U.S.
population is 1.76 x 10-6 for all registered foods. Adding
in calculated risks from catfish and the average monitoring value of
0.8 ppb diuron parent in all drinking water, the total estimation of
cancer risk for the U.S. population is 2.71 x 10-6. This
value does not include contributions from linuron and propanil
metabolites because, as explained in the toxicological endpoints
section, the tumor target organs are different for diuron when compared
to linuron and propanil and because mechanistic and metabolism data
indicate that diuron may be inducing tumors through a different
mechanism of action. Metabolites in water are also not included;
however, EFED's upper end value of diuron parent in surface water
partially compensates for not including metabolites in water.
5. Determination of safety. Based on these risk assessments, EPA
concludes that there is a reasonable certainty that no harm will result
from aggregate exposure to diuron residues.
E. Aggregate Risks and Determination of Safety for Infants and Children
1. Safety factor for infants and children-- i. In general. In
assessing the potential for additional sensitivity of infants and
children to residues of diuron, EPA considered data from developmental
toxicity studies in the rat and rabbit and a 2-generation reproduction
study in the rat. The developmental toxicity studies are designed to
evaluate adverse effects on the developing organism resulting from
maternal pesticide exposure during gestation. Reproduction studies
provide information relating to effects from exposure to the pesticide
on the reproductive capability of mating animals and data on systemic
toxicity.
FFDCA section 408 provides that EPA shall apply an additional
tenfold margin of safety for infants and children in the case of
threshold effects to account for pre- and postnatal toxicity and the
completeness of the data base unless EPA determines that a different
margin of safety will be safe for infants and children. Margins of
safety are incorporated into EPA risk assessments either directly
through use of a margin of exposure (MOE) analysis or through using
uncertainty (safety) factors in calculating a dose level that poses no
appreciable risk to humans. EPA believes that reliable data support
using the standard MOE and uncertainty factor (usually 100 for combined
inter- and intra-species variability) and not the additional tenfold
MOE/uncertainty factor when EPA has a complete data base under existing
guidelines and when the severity of the effect in infants or children
or the potency or unusual toxic properties of a compound do not raise
concerns regarding the adequacy of the standard MOE/safety factor.
ii. Developmental toxicity studies--Rats. In the developmental
study in rats, the maternal (systemic) NOAEL was 16 mg/kg/day, based on
reduction in body weight and food consumption at the LOAEL of 80 mg/kg/
day. The developmental (fetal) NOAEL was 80 mg/kg/day, based on
increases in delayed ossification of vertebrae and sternebrae as well
as decreased fetal weights at the LOAEL of 400 mg/kg/day.
Rabbits. In the developmental toxicity study in rabbits, the
maternal (systemic) NOAEL was 10 mg/kg/day, based on decreased body
weight and food comsumption at the LOAEL of 50 mg/kg/day. The
developmental (pup) NOAEL was 50 mg/kg/day, the highest dose tested.
There were no developmental effects.
iii. Reproductive toxicity study--Rats. In the 2-generation
reproductive toxicity study in rats, the parental (systemic) NOAEL was
16.9 (males) and 20.3 (females) mg/kg/day, based on decreased body
weight, body weight gain and food consumption in both sexes at the
LOAEL of 120 (males) and 144 (females) mg/kg/day. The developmental
(pup) NOAEL was 20.3 mg/kg/day, based on decreased pup body weight
during the lactation period for both sexes and generations at the LOAEL
of 144 mg/kg/day. The reproductive NOAEL was 120 (males) and 144
(females) mg/kg/day, the highest dose tested. There were no
reproductive effects.
iv. Pre- and postnatal sensitivity. The toxicological data base for
evaluating pre- and postnatal toxicity for diuron is complete with
respect to current data requirements. Based on the developmental and
reproductive toxicity studies discussed above for diuron, there does
not appear to be an extra sensitivity for pre- or postnatal effects.
EPA has concluded that the FQPA Safety Factor can be removed (1x) in
assessing the risk posed by this chemical. The decision applies only to
this tolerance action.
v. Conclusion. There is a complete toxicity data base for diuron
and exposure data are complete or are estimated based on data that
reasonably accounts for potential exposures.
2. Acute risk. The acute dietary risk analysis using partially
refined data estimated that the acute dietary exposure (food only) for
the population subgroup, non-nursing infants will utilize 24% of the
acute RfD (PAD). All other infant and children population subgroups
have acute risk estimates (food only) below that of non-nursing infants
(see discussion on residue contributions in the Acute Aggregate Risk
section for the U.S. population). For DCA-convertible residues from
diuron, linuron and propanil, it was determined that an acute dietary
exposure (food plus water) of 100% or less of the acute RfD (PAD) is
acceptable to protect the safety of all infant and children population
subgroups. The estimated exposures at the 99.9th percentile for all
infant and children population subgroups utilize less than 100% of the
Acute RfD, which, because there is no FQPA 10x Safety Factor, is
identical to the acute PAD.
As stated in the aggregate risk section for the U.S. population,
for purposes of risk assessment, the estimated maximum concentration of
14 ppb from the monitoring data will be used for comparison to the
back-calculated human health DWLOC for the acute endpoint. For the
DWLOC calculations, the EPA default body weights are:
[[Page 41303]]
Females (13+ years old), 60 kg and all infants/children, 10 kg.
EPA has used daily drinking rates of 2L/day for adults and 1L/day
for children.
The DWLOCs are between 1,200 and 4,300 ppb for acute dietary risk.
Based on a comparison of the calculated DWLOCs and the estimated
exposure to diuron in drinking water (14 ppb), EPA does not expect the
aggregate exposure to exceed 100% of the Acute RfD for either infants
or children. The DWLOCs are approximately 100 times higher than the
maximum value observed in monitoring studies. Therefore, EPA concludes
that there is a reasonable certainty that no harm will result to either
infants or children from acute aggregate exposure to diuron residues.
3. Chronic risk. Using the exposure assumptions described in this
unit, EPA has concluded that aggregate exposure to diuron from food
will utilize 28% of the chronic RfD for non-nursing infants, which is
the highest exposed population subgroup. All other infant and children
population subgroups have lower chronic dietary exposure. EPA generally
has no concern for exposures below 100% of the chronic RfD (PAD)
because the chronic RfD (PAD) represents the level at or below which
daily aggregate dietary exposure over a lifetime will not pose
appreciable risks to human health. There are no registered residential
uses for diuron. EPA concludes that there is a reasonable certainty
that no harm will result to infants and children from chronic aggregate
exposure to DCA residues from diuron, linuron and propanil. Despite the
potential for exposure to diuron in drinking water and from non-
dietary, non-occupational exposure, EPA does not expect the aggregate
exposure to exceed 100% of the RfD/PAD.
4. Short- or intermediate-term risk. Short- and intermediate-term
aggregate exposure takes into account chronic dietary food and water
(considered to be a background exposure level) plus non-dietary, non-
occupational exposures. Since there are no registered uses of diuron
which would result in such exposures, short- and intermediate- term
aggregate risk estimates were not conducted.
5. Determination of safety. Based on these risk assessments, EPA
concludes that there is a reasonable certainty that no harm will result
to infants and children from aggregate exposure to diuron residues.
IV. Other Considerations
A. Metabolism in Plants and Animals
The nature of the residue in plants is adequately understood. The
parent compound usually comprises only a small portion of the total
residue. Significant residues formed by demethylation include
dichlorophenylmethylurea (DCPMU) and dichlorophenylurea (DCPU).
Although tolerances in 40 CFR 180.106 are expressed simply as
``residues of the herbicide diuron,'' as part of the reregistration
process EPA has noted that the residue to be regulated in plants is
diuron and its related compounds convertible to 3,4-dichloroaniline as
determined by the enforcement and data collection methods. The
tolerance expression should be revised in this manner when
reregistration eligibility decisions are made for diuron. For the
purposes of the current action, the tolerance will be based on the
combined residues of diuron and its metabolites convertible to 3,4-
dichloroaniline.
EPA addressed the residues of concern in livestock commodities.
While DCPMU and DCPU are also formed in livestock, five hydroxylated
metabolites are found that are not observed in plants. EPA concluded
these residues are not of concern in livestock tissues and eggs as the
DCA method determined 80% or more of the total radioactive residue in
these commodities. In milk the DCA method recovered only 10% of the TRR
and EPA concluded that while the remaining 90% of the residue need not
be quantified using a different method, the diuron residues observed in
milk (by conversion to DCA) in the feeding study will be multiplied by
10 for purposes of risk assessment. Although livestock are not directly
involved in this tolerance action, a tolerance is being established for
residues in catfish. For the purposes of this tolerance, the residue of
concern in catfish will be considered the same as in plants and
livestock tissues (i.e., diuron and it metabolites convertible to DCA).
B. Analytical Enforcement Methodology
Adequate enforcement methodology (example - gas chromotography) is
available to enforce the tolerance expression. The method may be
requested from: Calvin Furlow, PIRIB, IRSD (7502C), Office of Pesticide
Programs, Environmental Protection Agency, 401 M St., SW., Washington,
DC 20460. Office location and telephone number: Rm 101FF, Crystal Mall
#2, 1921 Jefferson Davis Hwy., Arlington, VA, (703) 305-5229.
C. Magnitude of Residues
Residue data were provided for four different application schemes
to catfish ponds. In all cases, the application rate or concentration
(0.01 ppm) in the water was the same as that authorized in the section
18 exemptions. In three ponds, the treatments were made every 5 days
(versus proposed 7-day interval) with the total number of applications
being 7, 13 or 19 (for total treatment periods of 30, 60 or 90 days).
The maximum DCA-containing residues in catfish fillets for the three
treatment patterns were 0.90, 1.76 and 1.52 ppm, respectively. The
values apparently reflect averages of triplicate analyses. The highest
residue from an individual analysis is 1.88 ppm. The fourth pond
(described as an efficacy study) more closely resembled the proposed
emergency use in that the 0.01 ppm water treatments were made every 7
days, although more applications were made (17 over 112 days versus
maximum of 9 requested in the section 18). Fillets were collected after
the final treatment and found to contain 0.59-1.16 ppm total DCA-
containing residues. Based on these data, EPA concludes that a 2.0 ppm
time-limited tolerance should be established for residues of diuron and
its metabolites convertible to 3,4-dichloroaniline in catfish fillets.
There are no livestock feed items associated with the proposed use
in catfish ponds. Therefore, tolerances are not required for residues
of diuron and metabolites in meat, milk, poultry and eggs. Tolerances
of 1 ppm are established for residues of diuron in the meat, fat and
meat byproducts of cattle, goats, hogs, horses and sheep (40 CFR
180.106) in conjunction with registered uses of the herbicide.
D. International Residue Limits
There are no Codex, Canadian, or Mexican tolerances or maximum
residue limits for diuron in catfish. Therefore, harmonization with
international tolerances is not an issue for this tolerance.
E. Rotational Crop Restrictions
Since the requested use is for catfish ponds, which are essentially
permanent structures, there are no rotational crops that would be
planted in the treated areas. Thus, no plantback intervals need to be
specified for rotational crops.
V. Conclusion
Therefore, the tolerance is established for combined residues of
diuron and its metabolites convertible to 3,4-dichloroaniline in
catfish fillets at 2.0 ppm.
[[Page 41304]]
VI. Objections and Hearing Requests
The new FFDCA section 408(g) provides essentially the same process
for persons to ``object'' to a tolerance regulation as was provided in
the old section 408 and in section 409. However, the period for filing
objections is 60 days, rather than 30 days. EPA currently has
procedural regulations which govern the submission of objections and
hearing requests. These regulations will require some modification to
reflect the new law. However, until those modifications can be made,
EPA will continue to use those procedural regulations with appropriate
adjustments to reflect the new law.
Any person may, by September 28, 1999, file written objections to
any aspect of this regulation and may also request a hearing on those
objections. Objections and hearing requests must be filed with the
Hearing Clerk, at the address given under the ``ADDRESSES'' section (40
CFR 178.20). A copy of the objections and/or hearing requests filed
with the Hearing Clerk should be submitted to the OPP docket for this
rulemaking. The objections submitted must specify the provisions of the
regulation deemed objectionable and the grounds for the objections (40
CFR 178.25). Each objection must be accompanied by the fee prescribed
by 40 CFR 180.33(i). EPA is authorized to waive any fee requirement
``when in the judgement of the Administrator such a waiver or refund is
equitable and not contrary to the purpose of this subsection.'' For
additional information regarding tolerance objection fee waivers,
contact James Tompkins, Registration Division (7505C), Office of
Pesticide Programs, Environmental Protection Agency, 401 M St., SW.,
Washington, DC 20460. Office location, telephone number, and e-mail
address: Rm. 239, Crystal Mall #2, 1921 Jefferson Davis Hwy.,
Arlington, VA, (703) 305-5697, tompkins.jim@epa.gov. Requests for
waiver of tolerance objection fees should be sent to James Hollins,
Information Resources and Services Division (7502C), Office of
Pesticide Programs, Environmental Protection Agency, 401 M St., SW.,
Washington, DC 20460.
If a hearing is requested, the objections must include a statement
of the factual issues on which a hearing is requested, the requestor's
contentions on such issues, and a summary of any evidence relied upon
by the requestor (40 CFR 178.27). A request for a hearing will be
granted if the Administrator determines that the material submitted
shows the following: There is genuine and substantial issue of fact;
there is a reasonable possibility that available evidence identified by
the requestor would, if established, resolve one or more of such issues
in favor of the requestor, taking into account uncontested claims or
facts to the contrary; and resolution of the factual issues in the
manner sought by the requestor would be adequate to justify the action
requested (40 CFR 178.32). Information submitted in connection with an
objection or hearing request may be claimed confidential by marking any
part or all of that information as CBI. Information so marked will not
be disclosed except in accordance with procedures set forth in 40 CFR
part 2. A copy of the information that does not contain CBI must be
submitted for inclusion in the public record. Information not marked
confidential may be disclosed publicly by EPA without prior notice.
VII. Public Record and Electronic Submissions
EPA has established a record for this regulation under docket
control number [OPP-300881] (including any comments and data submitted
electronically). A public version of this record, including printed,
paper versions of electronic comments, which does not include any
information claimed as CBI, is available for inspection from 8:30 a.m.
to 4 p.m., Monday through Friday, excluding legal holidays. The public
record is located in Room 119 of the Public Information and Records
Integrity Branch, Information Resources and Services Division (7502C),
Office of Pesticide Programs, Environmental Protection Agency, Crystal
Mall #2, 1921 Jefferson Davis Hwy., Arlington, VA.
Objections and hearing requests may be sent by e-mail directly to
EPA at:
opp-docket@epa.gov
E-mailed objections and hearing requests must be submitted as an
ASCII file avoiding the use of special characters and any form of
encryption.
The official record for this regulation, as well as the public
version, as described in this unit will be kept in paper form.
Accordingly, EPA will transfer any copies of objections and hearing
requests received electronically into printed, paper form as they are
received and will place the paper copies in the official record which
will also include all comments submitted directly in writing. The
official record is the paper record maintained at the Virginia address
in ``ADDRESSES'' at the beginning of this document.
VIII. Regulatory Assessment Requirements
A. Certain Acts and Executive Orders
This final rule establishes a tolerance under section 408 of the
FFDCA. The Office of Management and Budget (OMB) has exempted these
types of actions from review under Executive Order 12866, entitled
Regulatory Planning and Review (58 FR 51735, October 4, 1993). This
final rule does not contain any information collections subject to OMB
approval under the Paperwork Reduction Act (PRA), 44 U.S.C. 3501 et
seq., or impose any enforceable duty or contain any unfunded mandate as
described under Title II of the Unfunded Mandates Reform Act of 1995
(UMRA) (Pub. L. 104-4). Nor does it require special considerations as
required by Executive Order 12898, entitled Federal Actions to Address
Environmental Justice in Minority Populations and Low-Income
Populations (59 FR 7629, February 16, 1994), or require OMB review in
accordance with Executive Order 13045, entitled Protection of Children
from Environmental Health Risks and Safety Risks (62 FR 19885, April
23, 1997).
In addition, since tolerances and exemptions that are established
under FFDCA section 408(l)(6), such as the tolerance in this final
rule, do not require the issuance of a proposed rule, the requirements
of the Regulatory Flexibility Act (RFA) (5 U.S.C. 601 et seq.) do not
apply. Nevertheless, the Agency previously assessed whether
establishing tolerances, exemptions from tolerances, raising tolerance
levels or expanding exemptions might adversely impact small entities
and concluded, as a generic matter, that there is no adverse economic
impact. The factual basis for the Agency's generic certification for
tolerance actions published on May 4, 1981 (46 FR 24950), and was
provided to the Chief Counsel for Advocacy of the Small Business
Administration.
B. Executive Order 12875
Under Executive Order 12875, entitled Enhancing the
Intergovernmental Partnership (58 FR 58093, October 28, 1993), EPA may
not issue a regulation that is not required by statute and that creates
a mandate upon a State, local or tribal government, unless the Federal
government provides the funds necessary to pay the direct compliance
costs incurred by those governments. If the mandate is unfunded, EPA
must provide to OMB a description of the extent of EPA's prior
consultation with representatives of affected State, local, and tribal
[[Page 41305]]
governments, the nature of their concerns, copies of any written
communications from the governments, and a statement supporting the
need to issue the regulation. In addition, Executive Order 12875
requires EPA to develop an effective process permitting elected
officials and other representatives of State, local, and tribal
governments ``to provide meaningful and timely input in the development
of regulatory proposals containing significant unfunded mandates.''
Today's rule does not create an unfunded Federal mandate on State,
local, or tribal governments. The rule does not impose any enforceable
duties on these entities. Accordingly, the requirements of section 1(a)
of Executive Order 12875 do not apply to this rule.
C. Executive Order 13084
Under Executive Order 13084, entitled Consultation and Coordination
with Indian Tribal Governments (63 FR 27655, May 19, 1998), EPA may not
issue a regulation that is not required by statute, that significantly
or uniquely affects the communities of Indian tribal governments, and
that imposes substantial direct compliance costs on those communities,
unless the Federal government provides the funds necessary to pay the
direct compliance costs incurred by the tribal governments. If the
mandate is unfunded, EPA must provide OMB, in a separately identified
section of the preamble to the rule, a description of the extent of
EPA's prior consultation with representatives of affected tribal
governments, a summary of the nature of their concerns, and a statement
supporting the need to issue the regulation. In addition, Executive
Order 13084 requires EPA to develop an effective process permitting
elected officials and other representatives of Indian tribal
governments ``to provide meaningful and timely input in the development
of regulatory policies on matters that significantly or uniquely affect
their communities.''
Today's rule does not significantly or uniquely affect the
communities of Indian tribal governments. This action does not involve
or impose any requirements that affect Indian tribes. Accordingly, the
requirements of section 3(b) of Executive Order 13084 do not apply to
this rule.
IX. Submission to Congress and the Comptroller General
The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the
Small Business Regulatory Enforcement Fairness Act of 1996, generally
provides that before a rule may take effect, the Agency promulgating
the rule must submit a rule report, which includes a copy of the rule,
to each House of the Congress and 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 the rule in the Federal Register. This 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: July 14, 1999.
James Jones,
Director, Registration Division, Office of Pesticide Programs.
Therefore, 40 CFR chapter I is amended as follows:
PART 180--[AMENDED]
1. The authority citation for part 180 continues to read as
follows:
Authority: 21 U.S.C. 321(q), 346(a) and 371.
2. Section Sec. 180.106, is amended by adding new paragraph (b) to
read as follows.
Sec. 180.106 Diuron; tolerances for residues.
* * * * *
(b) Section 18 emergency exemptions. Time-limited tolerances are
established for combined residues of the herbicide diuron and its
metabolites convertible to 3,4-dichloroaniline in connection with use
of the pesticide under section 18 emergency exemptions granted by EPA.
These tolerances will expire and are revoked on the dates specified in
the following table.
------------------------------------------------------------------------
Parts Expiration/
Commodity per Revocation
million date
------------------------------------------------------------------------
Catfish fillets................................... 2.0 06/30/01
------------------------------------------------------------------------
* * * * *
[FR Doc. 99-19591 Filed 7-29-99; 8:45 am]
BILLING CODE 6560-50-F
