97-16213. Notice of Filing of Pesticide Petitions  

  • [Federal Register Volume 62, Number 119 (Friday, June 20, 1997)]
    [Notices]
    [Pages 33641-33647]
    From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
    [FR Doc No: 97-16213]
    
    
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    ENVIRONMENTAL PROTECTION AGENCY
    
    [PF-743; FRL-5723-7]
    
    
    Notice of Filing of Pesticide Petitions
    
    AGENCY: Environmental Protection Agency (EPA).
    
    ACTION: Notice.
    
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    SUMMARY: This notice announces the initial filing of pesticide 
    petitions proposing the establishment of regulations for residues of 
    certain pesticide chemicals in or on various food commodities.
    DATES: Comments, identified by the docket control number PF-743, must 
    be received on or before July 21, 1997.
    ADDRESSES: By mail submit written comments to: Public Information and 
    Records Integrity Branch (7506C), Information Resources and Services 
    Division, Office of Pesticides Programs, Environmental Protection 
    Agency, 401
    
    [[Page 33642]]
    
    M St., SW., Washington, DC 20460. In person bring comments to: Rm. 
    1132, CM #2, 1921 Jefferson Davis Highway, Arlington, VA.
        Comments and data may also be submitted electronically by following 
    the instructions under ``SUPPLEMENTARY INFORMATION.'' No confidential 
    business information should be submitted through e-mail.
        Information submitted as a comment concerning this document may be 
    claimed confidential by marking any part or all of that information as 
    ``Confidential Business Information'' (CBI). CBI should not be 
    submitted through e-mail. Information marked as CBI will not be 
    disclosed except in accordance with procedures set forth in 40 CFR part 
    2. A copy of the comment that does not contain CBI must be submitted 
    for inclusion in the public record. Information not marked confidential 
    may be disclosed publicly by EPA without prior notice. All written 
    comments will be available for public inspection in Rm. 1132 at the 
    address given above, from 8:30 a.m. to 4 p.m., Monday through Friday, 
    excluding legal holidays.
    
    FOR FURTHER INFORMATION CONTACT: The Product Manager/Regulatory Leader 
    listed in the table below:
    
    ------------------------------------------------------------------------
      Product Manager/Regulatory       Office location/                     
                Leader                 telephone number          Address    
    ------------------------------------------------------------------------
    Marion Johnson (PM 10)........  Rm. 210, CM #2, 703-    1921 Jefferson  
                                     305-6788, e-            Davis Hwy,     
                                     mail:[email protected]   Arlington, VA  
                                     pamail.epa.gov.                        
    Indira Gairola (Reg. Leader)..  4th floor, CS #1, 703-  2800 Crystal    
                                     308-8371, e-mail:       Drive,         
                                     [email protected]   Arlington, VA  
                                     l.epa.gov.                             
    ------------------------------------------------------------------------
    
    SUPPLEMENTARY INFORMATION: EPA has received pesticide petitions as 
    follows proposing the establishment and/or amendment of regulations for 
    residues of certain pesticide chemicals in or on various food 
    commodities under section 408 of the Federal Food, Drug, and Comestic 
    Act (FFDCA), 21 U.S.C. 346a. EPA has determined that these petitions 
    contain data or information regarding the elements set forth in section 
    408(d)(2); however, EPA has not fully evaluated the sufficiency of the 
    submitted data at this time or whether the data supports granting of 
    the petition. Additional data may be needed before EPA rules on the 
    petition.
        The official record for this notice of filing, as well as the 
    public version, has been established for this notice of filing under 
    docket control number [PF-743] (including comments and data submitted 
    electronically as described below). A public version of this record, 
    including printed, paper versions of electronic comments, which does 
    not include any information claimed as CBI, is available for inspection 
    from 8:30 a.m. to 4 p.m., Monday through Friday, excluding legal 
    holidays. The official record is located at the address in 
    ``ADDRESSES'' at the beginning of this document.
        Electronic comments can be sent directly to EPA at:
        opp-docket@epamail.epa.gov
    
    
        Electronic comments must be submitted as an ASCII file avoiding the 
    use of special characters and any form of encryption. Comment and data 
    will also be accepted on disks in Wordperfect 5.1 file format or ASCII 
    file format. All comments and data in electronic form must be 
    identified by the docket number [PF-743] and appropriate petition 
    number. Electronic comments on this notice may be filed online at many 
    Federal Depository Libraries.
    
    List of Subjects
    
        Environmental protection, Agricultural commodities, Food additives, 
    Feed additives, Pesticides and pests, Reporting and recordkeeping 
    requirements.
    
        Dated: June 12,1997
    
    James Jones,
    
    Acting Director, Registration Division, Office of Pesticide Programs.
    
    Summaries of Petitions
    
        Petitioner summaries of the pesticide petitions are printed below 
    as required by section 408(d)(3) of the FFDCA. The summaries of the 
    petitions were prepared by the petitioners and represent the views of 
    the petitioners. EPA is publishing the petition summaries verbatim 
    without editing them in any way. The petition summary announces the 
    availability of a description of the analytical methods available to 
    EPA for the detection and measurement of the pesticide chemical 
    residues or an explanation of why no such method is needed.
    
    1. Rhone-Poulenc Ag Company
    
     PP-7F4832
    
        EPA has received pesticide petition PP-7F4832 from Rhone-Poulenc Ag 
    Company, P.O. Box 12014, 2 T.W. Alexander Drive, Research Triangle 
    Park, NC 27709. This petition proposes, pursuant to section 408(d) of 
    the Federal Food, Drug and Cosmetic Act (FFDCA), 21 U.S.C.346a, to 
    amend 40 CFR part 180 by establishing a tolerance for the combined 
    residues of the insecticide fipronil (5-amino-1-[2,6-dichloro-4-
    (trifluoro-methyl)phenyl]-4-[1R, S)-(trifluoromethyl)sulfinyl]-1H-
    pyrazole-3-carbonitrile) and its metabolites 5-amino-1-[2,6-dichloro-4-
    (trifluoromethyl)phenyl]-4-[(trifluoromethyl) sulfonyl]-1H-pyrazole-3-
    carbonitrile; and 5-amino-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-
    [(trifluoromethyl)thio]-1H-pyrazole-3-carbonitrile; and 5-amino-1-[2,6-
    dichloro-4-(trifluoromethyl)phenyl]-4-[(1RS)-(trifluoromethyl)]-1H-
    pyrazole-3-carbonitrile on or in the following raw agricultural 
    commodities: potatoes at 0.02 parts per million (ppm), sweet potatoes 
    at 0.02 ppm, rice grain at 0.02 ppm, rice straw at 0.10 ppm, cottonseed 
    at 0.05 ppm, and cotton gin trash at 3.0 ppm. The proposed analytical 
    method is by gas chromatography using a Ni63 electron capture or mass 
    selective detector. EPA has determined that the petitions contain data 
    or information regarding the elements set forth in section 408(d)(2) of 
    the FFDCA; however, EPA has not fully evaluated the sufficiency of the 
    submitted data at this time or whether the data supports granting of 
    this petition. Additional data may be needed before EPA rules on the 
    petition.
    
    A. Residue Chemistry
    
        1.  Metabolism. The metabolism of fipronil is adequately 
    understood. Adequate data on the nature of the residues in both plant 
    and animals, including identification of major metabolites and 
    degradates of fipronil, are available. In plants and animal the 
    metabolism of fipronil proceeds via oxidation of the sulfoxide to yield 
    sulfone MB 46136 and hydrolysis of nitrile to yield amide RPA 200766. A 
    limited amount of reduction of sulfoxide to yield sulfide MB 45950 
    occurs in some cases. In cases where
    
    [[Page 33643]]
    
    fipronil is exposed to light for extended periods of time (i.e., foliar 
    applications), photo products MB 46513 and RAP 104615 are often 
    observed. Further transformation of the primary metabolites affords 
    minor amounts of carboxylic acid RPA 200761, amide RPA 105320 and 4-
    protiopyrazole MB 45897.
        2.  Practical analytical method. Validated analytical methods are 
    available for detecting and measuring levels of fipronil and its 
    metabolites in field corn, cotton, potato and rice raw agricultural 
    commodities and their respective processing fractions and animal 
    tissues. Residues are extracted from corn grain, fodder and forage with 
    75:25 acetonitrile: water and from the remaining corn substrates with 
    acetonitrile. Acetonitrile: water is also used to extract residues from 
    cottonseed, cotton gin by-products (gin trash), hulls and meal and rice 
    grain and straw. An aliquot of the extract is partioned against hexane 
    to remove lipids. After the addition of water and the removal of 
    acetonitrile, fipronil and its metabolites are then partitioned into 
    dichloromethane. Column chromatography is utilized for clean up / 
    removal of coextractive unknowns. For potato tubers, wet peel, dry 
    peel, flakes and chips and animal tissues, the extraction solvent is a 
    mixture of acetonitrile:acetone (70:30). Samples clean up is effected 
    by column chromatography. Quantification of fipronil and its 
    metabolites is accomplished by gas chromatography using a Ni63 electron 
    capture or mass selective detector.
    
    B. Toxicology Profile
    
        1. Acute toxicity. The acute oral LD50 in rats is 97 mg/
    kg. The dermal LD50 values in rats and rabbits are greater 
    than 2,000 mg/kg and 354 mg/kg, respectively. The inhalation 
    LC50 for a 4-hour exposure (nose only) is 0.39 mg/L. Slight 
    skin and moderate eye irritation are observed in rabbits with complete 
    clearing within 7 days for skin and 14 days for eye. Fipronil is not a 
    dermal sensitizer in guinea pigs (Buehler method).
        2. Genotoxicity. Fipronil was negative in both in vitro and in vivo 
    assays conducted to investigate gene mutations, DNA damage, and 
    chromosomal aberrations.
        3.  Developmental/reproductive effects. Rat and rabbit 
    developmental toxicity studies were negative at doses up to 20 mg/kg/
    day and 1 mg/kg/day, respectively. In a two-generation rat study, the 
    NOEL for reproductive toxicity was 30 ppm (2.64 mg/kg/day for both 
    sexes combined).
        4.  Subchronic effects. The NOELs in rats and dogs were 5 ppm (0.35 
    mg/kg/day for both sexes combined) and 2 mg/kg/day, respectively.
        5.  Chronic effects. The NOELs in 1-year dietary dog and 2-year 
    dietary rat studies were 0.3 mg/kg/day and 0.5 ppm, respectively, based 
    on clinical signs. The chronic Reference Dose (RfD) of 0.0002 mg/kg/day 
    established by EPA is based on the NOEL from the chronic rat study 
    (equivalent to 0.02 mg/kg/day in male rats and 0.03 mg/kg/day in female 
    rats) divided by an uncertainty factor of 100 to account for inter- and 
    intra-species variation.
        6.  Carcinogenicity. Fipronil was not carcinogenic when 
    administered to mice at any dose level tested. In rats, thyroid tumors 
    were observed only at 300 ppm (highest dose tested) (HDT). Mechanistic 
    data indicate that these tumors are related to an imbalance of thyroid 
    hormones and are specific to the rat. EPA's Health Effects Division 
    Carcinogenicity Peer Review Committee classified fipronil in Group C 
    and recommended that RfD methodology, i.e. non-linear or threshold, be 
    used for the estimation of human risk.
        7.  Endocrine effects. No evidence of estrogenic or androgenic 
    effects were noted in any study with fipronil. No adverse effects on 
    mating or fertility indices and gestation, live birth, or weaning 
    indices were noted in a two-generation rat reproduction study. In a 
    developmental neurotoxicity study, devlopment of pups was delayed only 
    at a dose producing maternal toxicity which resulted in smaller, less 
    developed pups. However, even in the presence of maternal toxicity, the 
    pups developed fully and were comparable to controls by study 
    termination.
    
    C. Aggregate exposure/cumulative effects
    
        1. Dietary exposure. A chronic dietary assessment for fipronil use 
    in/on corn demonstrates that the most realistic scenario, i.e. 
    anticipated residues with estimated market share, results in exposures 
    of less than 32% of the RfD for all subgroups including the most 
    sensitive subgroup, children 1 to 6 years of age. Therefore, chronic 
    dietary exposure to fipronil residues from both primary and secondary 
    sources, as a result of its use on field corn, potatoes, rice, and 
    cotton does not represent a significant risk to any segment of the 
    population.
        An acute dietary analysis using tolerances, 100% market share, and 
    a NOAEL of 5.0 mg/kg from the acute neurotoxicity study results in 
    Margins of Exposure (MOEs) for all segments of the population of over 
    2,000 for the 95th percentile and over 1,000 for both the 99th and 
    99.9th percentile. A more realistic assessment using anticipated 
    residues would result in considerably higher MOEs. However, even with 
    extremely conservative assumptions, sufficient MOEs exist for acute 
    dietary exposure to fipronil residues from both primary and secondary 
    sources. Therefore, fipronil use on field corn, potatoes, rice, and 
    cotton does not represent a significant acute dietary risk to any 
    segment of the population.
        2.  Drinking water exposure. The combined factors of low mobility, 
    moderate persistence, and low application rates result in fipronil and 
    its metabolites having little potential to reach groundwater as a 
    result of movement through the soil profile or of surface run-off. 
    Thus, the potential for ground water and/or surface water contamination 
    by fipronil and its degradates is expected to be very low.
        3.  Non-occupational exposure . Fipronil is currently registered 
    for use on golf and commercial turfgrass under the brand name CHIPCO 
    CHOICETM and for treatment of cats and dogs for fleas and ticks under 
    the brand name FRONTLINE. These uses are not expected to contribute 
    significantly to overall exposure. Fipronil has an extremely low vapor 
    pressure and low dermal penetration. These properties minimize the 
    amount of actual exposure that might occur. The application of fipronil 
    on golf and commercial turf using a slit applicator which places the 
    granule well into or below the thatch reduces the likelihood of post 
    application exposure. Further, as these areas have only limited human 
    activity involving minimal dermal contact with treated turf, potential 
    exposure is expected to be negligible. Exposure due to the application 
    of FRONTLINE is also expected to be low. The particle size 
    characteristics of the spray product result in negligible inhalation 
    exposure while the use of gloves, as required on the label in 
    conjunction with the low dermal penetration rate of fipronil, result in 
    minimal exposure via the dermal route. The affinity of fipronil for the 
    sebum and hair of animals and its one to three month efficacy indicate 
    that the material remains on the pet and is not bioavailable to those 
    coming in contact with the pet. Pending uses which include use of 
    fipronil as a termiticide and use in ant/roach baits are also 
    anticipated to present negligible exposure.
        4.  Cumulative risk. Fipronil belongs to a novel chemical class of 
    insecticides known as phenylpyrazoles. It is the only compound from 
    this class of chemistry registered for use as an insecticide.
    
    [[Page 33644]]
    
     Fipronil exhibits a mode of action different from traditional 
    organophosphate, carbamate, or pyrethroid insecticides. Fipronil acts 
    by binding within the chloride channel of the GABA receptor. There is 
    no indication that effects from fipronil would be cumulative with any 
    other pesticide.
    
    D. Safety Determinations
    
        1.  U.S General population. Both aggregate and dietary exposure 
    assessments demonstrate that all current and pending uses of fipronil 
    do not pose any significant risk to the general population. Therefore, 
    based on a very complete database, there is reasonable certainty that 
    no harm will result from aggregate exposure to the chemical residue 
    including all anticipated dietary exposures and all other exposures for 
    which there is reliable information.
        2.  Infants and children. In assessing the potential for additional 
    sensitivity of infants and children to residues of fipronil, the 
    available developmental and reproductive toxicity studies were 
    considered. Developmental toxicity studies in two species indicate that 
    fipronil has no teratogenic potential at any dose level. Further, no 
    adverse effects on fetal development were observed in rats or rabbits 
    even in the presence of maternal toxicity. In a two-generation rat 
    reproduction study, effects on pups were seen only at the highest dose 
    tested in the presence of parental toxicity. In a developmental 
    neurotoxicity study, development of pups was delayed only at a dose 
    producing maternal toxicity which resulted in smaller, less developed 
    pups. However, even in the presence of maternal toxicity, the pups 
    developed fully and were comparable to controls by study termination. 
    Thus, maternal and developmental NOELs and LELs were comparable in all 
    studies indicating no increase susceptibility of developing organisms. 
    Further, the NOEL of 0.02 mg/kg/day from the 2-year rat study, which 
    was used to calculate the RfD for fipronil, is already lower than the 
    NOELs from developmental studies by a factor of 45 to 1,000 times. As a 
    hundredfold uncertainty factor is already used to calculate the RfD 
    which is based on a NOEL significantly lower than NOELs from all 
    developmental and reproductive studies, an additional uncertainty 
    factor is not warranted and the RfD of 0.0002 mg/kg/day is appropriate 
    for assessing risk to infants and children.
    
    E. International Tolerances
    
        There are no Codex maximum residue levels established for fipronil. 
    (Marion Johnson)
    
    2. Rhone-Poulenc Ag Company
    
     PP-5F4426
    
        EPA has received pesticide petition (PP) 5F4426 from Rhone-Poulenc 
    Ag Company, P.O. Box 12014, 2 T.W. Alexander Drive, Research Triangle 
    Park, NC 27709. This petition proposes, pursuant to section 408(d) of 
    the Federal Food, Drug and Cosmetic Act (FFDCA), 21 U.S.C. 346a, to 
    amend 40 CFR part 180 by establishing a tolerance for the combined 
    residues of the insecticide fipronil (5-amino-1-[2,6-dichloro-4-
    (trifluoromethyl)phenyl]-4-[1R, S)-(trifluoromethyl)sulfinyl]-1H-
    pyrazole-3-carbonitrile) and its metabolites 5-amino-1-[2,6-dichloro-4-
    (trifluoromethyl)phenyl]-4-[(trifluor omethyl) sulfonyl]-1H-pyrazole-3-
    carbonitrile; and 5-amino-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-
    [(trifluoromethyl)thio]-1H-pyrazole-3-carbonitrile on or in the 
    following raw agricultural commodities: corn grain at 0.02 parts per 
    million (ppm), corn forage at 0.15 ppm and corn stover at 0.15 ppm; in 
    the animal product commodities of cattle, goats, horses and sheep: fat 
    at 0.40 ppm, liver at 0.10 ppm, meat at 0.04 ppm, meat by-products 
    (except liver) at 0.04 ppm, beef kidney at 0.03 ppm, and milk fat at 
    0.70 ppm; in the animal product commodities of hogs: fat at 0.04 ppm, 
    liver at 0.02 ppm, meat at 0.01 ppm and meat by-products (except liver) 
    at 0.01 ppm; in the animal product commodities of poultry: eggs at 0.03 
    ppm, fat at 0.05 ppm and meat at 0.02 ppm. The proposed analytical 
    method is by gas chromatography using a Ni63 electron capture or mass 
    selective detector. EPA has determined that the petitions contain data 
    or information regarding the elements set forth in section 408(d) (2) 
    of the FFDCA; however, EPA has not fully evaluated the sufficiency of 
    the submitted data at this time or whether the data supports granting 
    of this petition. Additional data may be needed before EPA rules on the 
    petition.
        As required by section 408(d) of the FFDCA, as recently amended by 
    the Food Quality protection Act (FQPA), Rhone-Poulenc Ag Company 
    included in the petition a summary of the petition and authorization 
    for the summary to be published in the Federal Register in a notice of 
    receipt of the petition. The summary represents the views of Rhone-
    Poulenc Ag Company; EPA is in the process of evaluating the petition. 
    As required by section 408 (d)(3), EPA is including the summary as a 
    part of this notice of filing. EPA may have made minor edits to the 
    summary for the purpose of clarity.
    
    A. Residue Chemistry
    
        1. Metabolism. The metabolism of fipronil is adequately understood. 
    Adequate data on the nature of the residues in both plant and animals, 
    including identification of major metabolites and degradates of 
    fipronil, are available. In plants and animal the metabolism of 
    fipronil proceeds via oxidation of the sulfoxide to yield sulfone and 
    hydrolysis of nitrile to yield the amide. Fipronil and its sulfone and 
    amide constitute greater than 75% of the identified residues in all 
    studies. A limited amount of reduction of sulfoxide to yield the 
    sulfide occurs in some cases. Further transformation of the primary 
    metabolites affords minor amounts of the carboxylic acid, the amide and 
    the 4-protiopyrazole.
        2. Practical analytical method. A validated analytical method is 
    available for detecting and measuring levels of fipronil and its 
    metabolites in field corn raw agricultural commodities (grain, forage 
    and fodder) and its processing fractions (oil and starch). Residues are 
    extracted from corn grain, fodder and forage with 75:25 
    acetonitrile:water and from the remaining corn substrates with 
    acetonitrile. An aliquot of the extract is partitioned against hexane 
    to remove lipids. After the addition of water and the removal of 
    acetonitrile, fipronil and its metabolites are partitioned into 
    dichloromethane. Column chromatography is utilized for clean up / 
    removal of coextractive unknowns. Quantification of fipronil and its 
    metabolites is accomplished by gas chromatography using a Ni63 electron 
    capture or mass selective detector.
    
    B. Toxicology Profile
    
        1. Acute toxicity. The acute oral LD50 in rats is 97 mg/
    kg. The dermal LD50 values in rats and rabbits are greater 
    than 2,000 mg/kg and 354 mg/kg, respectively. The inhalation 
    LC50 for a 2-hour exposure (nose only) is 0.39 mg/L. Slight 
    skin and moderate eye irritation are observed in rabbits with complete 
    clearing within 7 days for skin and 14 days for eye. Fipronil is not a 
    dermal sensitizer in guinea pigs (Buehler method).
        2. Genotoxicity. Fipronil was negative in both in vitro and in vivo 
    assays conducted to investigate gene mutations, DNA damage, and 
    chromosomal aberrations.
        3. Developmental/reproductive effects. Rat and rabbit developmental
    
    [[Page 33645]]
    
    toxicity studies were negative at doses up to 20 mg/kg/day and 1 mg/kg/
    day, respectively. In a 2-generation rat study, the NOEL for 
    reproductive toxicity was 30 ppm (2.64 mg/kg/day for both sexes 
    combined).
        4. Subchronic effects. The NOELs in rats and dogs were 5 ppm (0.35 
    mg/kg/day for both sexes combined) and 2 mg/kg/day, respectively.
        5. Chronic effects. The NOELs in 1-year dietary dog and 2-year 
    dietary rat studies were 0.3 mg/kg/day and 0.5 ppm, respectively, based 
    on clinical signs. The chronic Reference Dose (RfD) of 0.0002 mg/kg/day 
    established by EPA is based on the NOEL from the chronic rat study 
    (equivalent to 0.02 mg/kg/day in male rats and 0.03 mg/kg/day in female 
    rats) divided by an uncertainty factor of 100 to account for inter- and 
    intra-species variation.
        6. Carcinogenicity. Fipronil was not carcinogenic when administered 
    to mice at any dose level tested. In rats, thyroid tumors were observed 
    only at 300 ppm (HDT). Mechanistic data indicate that these tumors are 
    related to an imbalance of thyroid hormones and are specific to the 
    rat. EPA's Health Effects Division Carcinogenicity Peer Review 
    Committee classified fipronil in Group C and recommended that RfD 
    methodology, i.e. non-linear or threshold, be used for the estimation 
    of human risk.
        7. Endocrine effects. No evidence of estrogenic or androgenic 
    effects were noted in any study with fipronil. No adverse effects on 
    mating or fertility indices and gestation, live birth, or weaning 
    indices were noted in a two-generation rat reproduction study. In a 
    developmental neurotoxicity study, development of pups was delayed only 
    at a dose producing maternal toxicity which resulted in smaller, less 
    developed pups. However, even in the presence of maternal toxicity, the 
    pups developed fully and were comparable to controls by study 
    termination.
    
    C. Aggregate Exposure/Cumulative Effects
    
        1. Dietary exposure. A chronic dietary assessment for fipronil use 
    in/on corn demonstrates that the most realistic scenario, i.e. 
    anticipated residues with estimated market share, results in exposures 
    of less than 3% of the RfD for all subgroups including the most 
    sensitive subgroup, children 1 to 6 years of age. Scenarios using 
    tolerances and estimated market share, as well as anticipated residues 
    and 100% crop treated, demonstrated exposures of less than 40% of the 
    RfD for the most sensitive subgroup (children 1 to 6 years of age) and 
    less than 15% of the RfD for the US population in general. Therefore, 
    chronic dietary exposure to fipronil residues from both primary and 
    secondary sources, as a result of its use on field corn, does not 
    represent a significant risk to any segment of the population.
        An acute dietary analysis using tolerances, assuming fipronil in 
    milk fat only with a tolerance of 0.7 ppm, 1989-92 consumption data, 
    and a NOAEL of 5.0 mg/kg from the acute neurotoxicity study results in 
    Margins of Exposure (MOEs) for all segments of the population of over 
    2,000 for the 95th percentile and over 1,000 for both the 99th and 
    99.9th percentile. A more realistic assessment using anticipated 
    residues would result in considerably higher MOEs. However, even with 
    extremely conservative assumptions, sufficient MOEs exist for acute 
    dietary exposure to fipronil residues from both primary and secondary 
    sources. Therefore, fipronil use on field corn does not represent a 
    significant acute dietary risk to any segment of the population.
        2. Drinking water exposure. The combined factors of low mobility, 
    moderate persistence, low application rates, and in-furrow application 
    result in fipronil and its metabolites having little potential to reach 
    groundwater as a result of movement through the soil profile or of 
    surface run-off. Thus, the potential for ground water and/or surface 
    water contamination by fipronil and its degradates is expected to be 
    very low.
        3. Non-occupational exposure. Fipronil is currently registered for 
    use on golf and commercial turfgrass under the brand name CHIPCO 
    CHOICETM and for treatment of cats and dogs for fleas and ticks under 
    the brand name FRONTLINE . These uses are not expected to contribute 
    significantly to overall exposure. Fipronil has an extremely low vapor 
    pressure and low dermal penetration. These properties minimize the 
    amount of actual exposure that might occur. The application of fipronil 
    on golf and commercial turf using a slit applicator which places the 
    granule well into or below the thatch reduces the likelihood of post 
    application exposure. Further, as these areas have only limited human 
    activity involving minimal dermal contact with treated turf, potential 
    exposure is expected to be negligible. Exposure due to the application 
    of FRONTLINE is also expected to be low. The particle 
    sizecharacteristics of the spray product result in negligible 
    inhalation exposure while the use of gloves, as required on the label 
    in conjunction with the low dermal penetration rate of fipronil, result 
    in minimal exposure via the dermal route. The affinity of fipronil for 
    the sebum and hair of animals and its one to three month efficacy 
    indicate that the material remains on the pet and is not bioavailable 
    to those coming in contact with the pet. Pending uses which include use 
    of fipronil as a termiticide and use in ant/roach baits are also 
    anticipated to present negligible exposure.
        4. Cumulative risk. Fipronil belongs to a novel chemical class of 
    insecticides known as phenylpyrazoles. It is the only compound from 
    this class of chemistry registered for use as an insecticide. Fipronil 
    exhibits a mode of action different from traditional organophosphate, 
    carbamate, or pyrethroid insecticides. Fipronil acts by binding within 
    the chloride channel of the GABA receptor. There is no indication that 
    effects from fipronil would be cumulative with any other pesticide.
    
    D. Safety Determinations
    
        5. U.S. general population. Both aggregate and dietary exposure 
    assessments demonstrate that all current and pending uses of fipronil 
    do not pose any significant risk to the general population. Therefore, 
    based on a very complete database, there is reasonable certainty that 
    no harm will result from aggregate exposure to the chemical residue 
    including all anticipated dietary exposures and all other exposures for 
    which there is reliable information.
        6. Infants and children. In assessing the potential for additional 
    sensitivity of infants and children to residues of fipronil, the 
    available developmental and reproductive toxicity studies were 
    considered. Developmental toxicity studies in two species indicate that 
    fipronil has no teratogenic potential at any dose level. Further, no 
    adverse effects on fetal development were observed in rats or rabbits 
    even in the presence of maternal toxicity. In a two-generation rat 
    reproduction study, effects on pups were seen only at the highest dose 
    tested in the presence of parental toxicity. In a developmental 
    neurotoxicity study, development of pups was delayed only at a dose 
    producing maternal toxicity which resulted in smaller, less developed 
    pups. However, even in the presence of maternal toxicity, the pups 
    developed fully and were comparable to controls by study termination. 
    Thus, maternal and developmental NOELs and LELs were comparable in all 
    studies indicating no increase susceptibility of developing organisms. 
    Further, the NOEL of 0.02 mg/kg/day from the 2-year rat study, which 
    was used to calculate the RfD for fipronil, is already lower
    
    [[Page 33646]]
    
    than the NOELs from developmental studies by a factor of 45 to 1,000 
    times. As a hundredfold uncertainty factor is already used to calculate 
    the RfD which is based on a NOEL significantly lower than NOELs from 
    all developmental and reproductive studies, an additional uncertainty 
    factor is not warranted and the RfD of 0.0002 mg/kg/day is appropriate 
    for assessing risk to infants and children.
    
    E. International Tolerances
    
        There are no Codex maximum residue levels established for fipronil. 
    (Marion Johnson)
    
    3. Zeneca Ag Products
    
    PP-6E4675
    
        EPA has received a pesticide petition (PP 6E4675) from Zeneca Ag 
    Products, 1800 Concord Pike, P.O. Box 15458, Wilmington, Delaware 
    19850-5458, proposing pursuant to 408(e) of the Federal Food, Drug, and 
    Cosmetic Act, 21 U.S.C. 346a(e), to amend 40 CFR 180.1001(d) by 
    establishing an exemption from the requirement for a tolerance for 
    residues of the inert ingredient titantium dioxide when used in 
    pesticide formulations used on growing crops.
        Pursuant to section 408 (d)(2)(A)(i) of the FFDCA, as amended, 
    Zeneca Ag Products has submitted the following summary of information, 
    data and arguments in support of their pesticide petition. This summary 
    was prepared by Zeneca and EPA has not fully evaluated the merits of 
    the petition. EPA edited the summary to clarify that the conclusions 
    and arguments were the petitioner's and not necessarily EPA's.
    
    A. Residue Chemistry
    
        Titanium(Ti) is the eighth most abundant element in the earth's 
    crust and consequently spontaneously enters the food chain to some 
    degree. Humans are estimated to consume approximately 300 g 
    Ti/day in food. Since the various forms of titanium, including titanium 
    dioxide, are so abundant as a background element, estimations of 
    residues resulting from use as an inert ingredient in a pesticide 
    formulation would not be of value in determining the overall impact of 
    this particular use.
        Analytical method. There are two approved AIHA methods for analysis 
    of titanium residues: (1) Hydrogen peroxide colormetric method with a 
    sensitivity of 2 g Ti; and (2) Atomic absorption with a 
    sensitivity of 1.9 g/ml.
    
    B. Toxicological Profile
    
        Titanium dioxide (TiO2) is the most commercially 
    important of all the titanium compounds. TiO2 is an opaque 
    powder that is approved for use as a colorant in cosmetics (21 CFR 
    73.2575 and 21 CFR 73.3126), pharmaceuticals (21 CFR 73.575) and foods, 
    as well as in an extensive range of industrial uses (e.g. paper, 
    paints, enamels and plastics) throughout the world. Titanium dioxide is 
    exempt from the requirement for a tolerance when used as a colorant in 
    pesticide formulations (40 CFR 180.1001). In the Federal Register of 
    June 20, 1988, EPA announced that it was deleting titanium dioxide from 
    the list of toxic chemicals under section 313 of Title III of the 
    Superfund Amendments. This rule concluded that titanium dioxide will 
    not cause significant adverse effects to humans or to the environment.
        The wide range of relatively unrestricted uses of titanium dioxide 
    reflects the fact that the compound is held to be toxicologically 
    inert, belonging to that group of materials classified as 
    Generally Accepted as Safe (GRAS). The scientific 
    committee on food coloring materials determined that no ADI need be set 
    for the use of titanium dioxide, as its use does not present any health 
    concerns (1983). Indeed, titanium dioxide is frequently used as a 
    negative control material in vivo chronic dust exposure studies and in 
    vivo assessments of fibrogenic potential of dusts.
        1. Acute toxicity. Titanium dioxide (TiO2) has very low 
    acute toxicity with no deaths in rats administered as much as 24 grams/
    Kg. No overt signs of toxicity occurred in a person that ingested 
    approximately 1 pound of TiO2. Skin and eye contact to the 
    dry powder produced no irritation to the skin and very slight 
    irritation to the eyes. An acute 4-hour inhalation exposure at 
    concentrations of 6.82 mg/L produced no mortalities. Intratracheal 
    administration also indicated a low level of acute toxicity. In a 2-
    week inhalation study, rats exposed to 1.92 mg/L showed a typical dust-
    cell reaction. Additionally, only a typical dust-cell reaction was 
    noted in rats exposed to 1 mg/L from 4-weeks up to 1-year.
        2. Genotoxicity. Titanium dioxide has no genotoxic potential as 
    judged from unequivocal negatives in a range of studies in vitro and in 
    vivo.
        3. Reproductive and developmental toxicity. No relevant data are 
    available for this material. However, the OECD Screening Information 
    Data Set (SIDS) Manual for 1996, which contains chemical data and 
    regulatory decisions agreed by scientists within the European 
    Community, stated that due to a lack of toxicity resulting from 
    subchronic and chronic exposure to titanium dioxide, specific testing 
    for reproductive and developmental toxicity were not required for 
    TiO2.
        4. Subchronic toxicity. Repeated doses ranging from 800 to 1,500 
    mg/kg of Titanium dioxide for 2-13 months did not produce adverse 
    effects in all species tested. Some of these studies were limited in 
    terms of the number of animals used ( group sizes were 1 to 4).
        In a comprehensive study reported as part of the NCI program, 
    groups of 50 male and 50 female F344 rats or B6C3F1 mice were fed diets 
    containing 25,000 or 50,000 ppm titanium dioxide for 103 weeks. Even 
    though these doses (equivalent to 1.25 g/kg or 2.5 g/kg in rats and 
    3.75 g/kg or 7.5 g/kg in mice) were very high (well in excess of the 
    modern guideline limit dose of 20,000 ppm in rat or 7,000 ppm in 
    mouse), there was no significant evidence of chronic toxicity.
        5. Chronic toxicity --a. Carcinogenicity. In an NCI study groups of 
    50 male and 50 female F344 rats or B6C3F1 mice were fed diets 
    containing 25,000 ppm or 50,000 ppm titanium dioxide for 103 weeks. 
    There were no compound-related increases in tumors. There was a non-
    statistically significant increase in C-cell adenoma and of thyroid 
    carcinoma in female rats which, it was concluded, was unrelated to 
    titanium dioxide.
        In a study in which F344 rats were fed diets containing up to 5% 
    mica coated with titanium dioxide there was no increase in tumors. In 
    addition, there were no tumors in rats or mice injected 
    intraperitoneally (single or multiple doses) or subcutaneously and 
    observed for periods of 18 months or longer.
        There are no epidemiological studies following purely oral exposure 
    to titanium dioxide. However, in studies of factory workers exposed to 
    titanium dioxide dust (primarily via inhalation) there was no evidence 
    of increased cancers.
        b. Pulmonary effects of eitanium dioxide. TiO2 is 
    considered generally to be inert and this is confirmed by the very low 
    acute inhalation toxicity (LC50 6.82 mg/L). Single 
    administration of TiO2 by intratracheal instillation may 
    produce changes in the alveolar cell population, lung lining fluid 
    components and lung tissues. Such changes, the majority of which 
    reversed rapidly even with very high lung loading, were consistent with 
    administration of a relatively high dose of an inert, insoluble dust 
    into the lung. The acceptance that TiO2 is relatively inert 
    in the lung has led to the use of this as a negative control in many 
    studies investigating the pulmonary
    
    [[Page 33647]]
    
    effects of particles. Results in the majority of these studies are 
    again consistent with the inert nature of this material.
        A number of repeat exposure inhalation studies have been conducted 
    to investigate either the inherent toxicity of TiO2 or again 
    to investigate the response of the lung to exposure to inert particles. 
    The majority of studies demonstrate that sub-chronic and chronic 
    exposure to realistic concentrations of TiO2 result in 
    minimal changes consistent with a steady accumulation of inert 
    particles in the lung.
        In a 2-year inhalation study, groups of 200 rats were exposed 6-
    hours a day, 5-days a week to 10, 50 or 250 mg/m of TiO2. 
    Survival of the exposed animals was comparable to that of the control 
    group, and there were no compound-related clinical signs of toxicity at 
    any dose level.
        In rats, white foci of accumulated material were apparent on the 
    visceral surface and throughout the lung parenchyma at gross necropsy. 
    At 10mg/m this was minimal but marked increases were noted at 50 mg/m 
    and particularly at 250 mg/m. Microscopically, these foci represented 
    not only aggregates of dust or dust containing cells but in most 
    instances the additional biological response of the lung (e.g. 
    pleurisy, collagenized fibrosis associated with cholesterol granulomas, 
    alveoli bronchiolarization, pneumonia, and alveolar cell hyperplasia) 
    to the persistent presence of inert particles. At 250 mg/m in this 
    study, and at 10 mg/m in a subsequent study using a different type 
    (ultrafine) of TiO2, resulted in an increased incidence of 
    lung tumors at termination. These tumors were either broncho-alveolar 
    or epidermoid/squamous. Such tumors are now known to be a common 
    response of the lung to excessive lung burdens of insoluble dusts, are 
    seen only in the rat and are of questionable relevance to man.
        A case-control epidemiology study of male employees exposed to 
    titanium dioxide did not demonstrate an increased risk for lung cancer. 
    In addition, there was no dose-response relationship between titanium 
    dioxide exposure and chronic respiratory disease, pleural thickening, 
    pleural plaques, or pleural nodules.
        6. Animal metabolism. Data on the absorption of titanium compounds 
    is limited. When male and female rats were fed diet containing 100 g 
    titanium dioxide per kg of diet, for about 32 days, no retention of 
    titanium occurred in the liver, spleen, kidney, bone, plasma or 
    erythrocytes. However, there were measurable amounts (0.06 and 0.11 mg/
    kg wet weight) in the muscles. Following intravenous injection of 250mg 
    titanium dioxide/kg to rats, there was an exponential disappearance 
    rate from the blood with only about 30% remaining after 10 minutes. 
    Seventy percent of the injected dose was detected in the liver after 5 
    minutes, rising to almost 80% by 15 minutes. The organ with the next 
    highest concentration was the spleen, after 6 hours. By 24 hours, the 
    highest concentration was in the celiac lymph nodes that drain the 
    lymph from the liver. 1-year after the single injection, the highest 
    tissue concentrations (178.9 mg/gm) were still in these lymph nodes.
        7. Human data. In a study involving five adult males, each of whom 
    consumed 5g on three consecutive days, there was no significant 
    increase in urinary content of titanium indicating there had been no 
    significant absorption/excretion of the compound. However, titanium 
    dioxide has been found in the lymphatic systems of three workers 
    employed in processing titanium dioxide pigments, indicating the 
    compound can access the tissues, following inhalation exposure. 
    Titanium dioxide is also known to have a long residence time ( in the 
    order of a year) in the lung.
    
    C. Aggregate Exposure
    
        Titanium dioxide is currently approved for use in a significant 
    number of pharmaceutical, cosmetic, industrial and food products. 
    Therefore, the potential for aggregate exposure from dietary and non-
    dietary routes does exist for titanium dioxide. However, the use of 
    titanium dioxide as an inert in a pesticide formulation would not be 
    expected to significantly raise the background levels found naturally 
    in the food chain or general environment. Also, since the acute, 
    subchronic and chronic toxicity testing has shown titanium dioxide to 
    be physiologically inert, there is no concern for adverse health 
    effects resulting from potential aggregate exposures.
    
    D. Cumulative effects
    
        Because of the low toxicity of titanium dioxide and because its 
    presence in the environment is primarily naturally-occurring, Zeneca 
    does not believe that there is any reason to be concerned about the 
    potential for cumulative effects of titanium dioxide and other 
    substances that may have a common mechanism of toxicity.
    
    E. Safety Determination
    
        Titanium dioxide has been shown to be physiologically inert by most 
    routes of exposure, and is classified as Generally Accepted 
    as Safe (GRAS). Based on this information, Zeneca believes 
    that is a reasonable certainty that no harm will result to infants, 
    children, or the general population from aggregate exposure to titanium 
    dioxide residues.
    
    F. Existing Tolerances or Tolerance Exemptions
    
        Titanium dioxide is currently approved by FDA for use in foods, 
    cosmetics and pharmaceuticals. Titanium dioxide also is exempt from the 
    requirement for a tolerance by EPA for use as a colorant in pesticide 
    formulations (40 CFR 180.1001). (Indira Gairola)
    
    [FR Doc. 97-16213 Filed 6-19-97; 8:45 am]
    BILLING CODE 6560-50-F
    
    
    

Document Information

Published:
06/20/1997
Department:
Environmental Protection Agency
Entry Type:
Notice
Action:
Notice.
Document Number:
97-16213
Dates:
Comments, identified by the docket control number PF-743, must be received on or before July 21, 1997.
Pages:
33641-33647 (7 pages)
Docket Numbers:
PF-743, FRL-5723-7
PDF File:
97-16213.pdf