Pesticides; tolerances in food, animal feeds, and raw agricultural commodities: Buprofezin,
[Federal Register: April 8, 2005 (Volume 70, Number 67)]
[Rules and Regulations]
[Page 17901-17908]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr08ap05-4]
ENVIRONMENTAL PROTECTION AGENCY
[OPP-2004-0412; FRL-7691-8]
Buprofezin; Pesticide Tolerance
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
SUMMARY: This regulation establishes tolerances for residues of buprofezin in or on avocado, papaya, star apple, black sapote, mango, sapodilla, canistel, mamey sapote, sugar apple, cherimoya, atemoya, custard apple, ilama, soursop, birida, guava, feijoa, jaboticaba, wax jambu, starfruit, passionfruit, and acerola at 0.30 parts per million (ppm); pome fruit at 0.30 ppm; peach at 9.0 ppm, meat (cattle, goat, hog, horse, and sheep) at 0.05 ppm; kidney (cattle, goat, hog, horse, and sheep) at 0.05 ppm.; lettuce, head at 5.0 ppm, Lettuce, leaf at 13.0 ppm, and Vegetable, cucurbit at 0.5 ppm; fruit, citrus, group 10 at 2.5 ppm; citrus, dried, pulp at 7.5 ppm; and citrus, oil at 80 ppm. Nichino America, Inc., Linden Park, Suite 501, 4550 New Linden Hill Road, Wilmington, DE 19808 requested these tolerances under the Federal Food, Drug, and Cosmetic Act (FFDCA), as amended by the Food Quality Protection Act of 1996 (FQPA).
DATES: This regulation is effective April 8, 2005. Objections and requests for hearings must be received on or before June 7, 2005.
ADDRESSES: To submit a written objection or hearing request follow the detailed instructions as provided in Unit VI. of the SUPPLEMENTARY INFORMATION. EPA has established a docket for this action under Docket identification (ID) number OPP-2004-0412. All documents in the docket are listed in the EDOCKET index at http://www.epa.gov/edocket. Although
listed in the index, some information is not publicly available, i.e., CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, is not placed on the Internet and will be publicly available only in hard copy form. Publicly available docket materials are available either electronically in EDOCKET or in hard copy at the Public Information and Records Integrity Branch (PIRIB), Rm. 119, Crystal Mall 2, 1801 S. Bell St., Arlington, VA. This docket facility is open from 8:30 a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The docket telephone number is (703) 305-5805.
FOR FURTHER INFORMATION CONTACT: Richard J. Gebken, Registration Division (7505C), Office of Pesticide Programs, Environmental Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460- 0001; telephone number: (703) 305-6701; e-mail address: gebken.richard@epa.gov.
SUPPLEMENTARY INFORMATION:
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General Information
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Does this Action Apply to Me?
You may be potentially affected by this action if you are an agricultural producer, food manufacturer, or pesticide manufacturer. Potentially affected entities may include, but are not limited to:
Crop production (NAICS 111), e.g., agricultural workers; greenhouse, nursery, and floriculture workers; farmers.
Animal production (NAICS 112), e.g., cattle ranchers and farmers, dairy cattle farmers, livestock farmers.
Food manufacturing (NAICS 311), e.g., agricultural workers; farmers; greenhouse, nursery, and floriculture workers; ranchers; pesticide applicators.
Pesticide manufacturing (NAICS 32532), e.g., agricultural workers; commercial applicators; farmers; greenhouse, nursery, and floriculture workers; residential users.
This listing is not intended to be exhaustive, but rather provides a guide for readers regarding entities likely to be affected by this action. Other types of entities not listed in this unit could also be affected. The North American Industrial Classification System (NAICS) codes have been provided to assist you and others in determining whether this action might apply to certain entities. If you have any questions regarding the applicability of this action to a particular entity, consult the person listed under FOR FURTHER INFORMATION CONTACT.
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How Can I Access Electronic Copies of this Document and Other Related Information?
In addition to using EDOCKET (http://www.epa.gov/edocket/), you may
access this Federal Register document electronically through the EPA Internet under the ``Federal Register'' listings at http://www.epa.gov/fedrgstr/. A frequently updated electronic version of 40 CFR part 180
is available at E-CFR Beta Site Two at http://www.gpoaccess.gov/ecfr/.
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Background and Statutory Findings
In the Federal Register of March 17, 2004 (69 FR 12676) (FRL-7347- 1), EPA issued a notice pursuant to section
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408(d)(3) of FFDCA, 21 U.S.C. 346a(d)(3), announcing the filing of a pesticide petition (PP 3E6636, 3E6741, and 3E6747) by Interregional Research Project Number (IR-4), 681 U.S. Highway 1 South, North Brunswick, NJ 08902 and Nichino America, Inc., Linden Park, Suite 501, 4550 New Linden Hill Road, Wilmington, DE 19808. The petition requested that 40 CFR 180.511 be amended by establishing a tolerance for residues of the insecticide buprofezin (2-[(1,1- dimethylethyl)imino]tetrahydro-3-(1-methylethyl)-5-phenyl-4H-1,3,5- thiadiazin-4-one), in or on the raw agricultural commodities: Fruit, pome, group 11, except apple and apple, pomace at 4.0 parts per million (ppm) (PP 3E6636), apple at 1.2 ppm (PP 3E6636), apple, pomace at 2.5 ppm (PP 3E6636), peach, apricot, and nectarine at 3.0 ppm (PP 3E6741), and avocado, papaya, star apple, black sapote, mango, sapodilla, canistel, mamey sapote, sugar apple, cherimoya, atemoya, custard apple, ilama, soursop, biriba, guava, feijoa, jaboticaba, wax jambu, starfruit, passionfruit, and acerola at 0.30 ppm (PP 3E6747).
In the Federal Register of June 21, 2000 (65 FR 38543) (FRL-6557- 3), EPA issued a notice pursuant to section 408(d)(3) of FFDCA, 21 U.S.C. 346a(d)(3), announcing the filing of a pesticide petition (PP 0F6087) by Nichino America, Inc., Linden Park, Suite 501, 4550 New Linden Hill Road, Wilmington, DE 19808, (formerly Aventis CropScience, formerly AgrEvo USA Company). The petition requested that 40 CFR 180.511 be amended by establishing a tolerance for residues of the insecticide buprofezin] (2-[(1,1-dimethylethyl)imino]tetrahydro-3-(1- methylethyl)-5-phenyl-4H-1,3,5-thiadiazin-4-one), in or on the following meat commodities; (Cattle, goats, hogs, horse, and sheep at 0.05 ppm) and kidney commodities for (cattle, goats, hogs, horse, and sheep at 0.05 ppm) respectively.
In the Federal Register of December 22, 2004 (69 FR 76719) (FRL- 7689-4), EPA issued a notice pursuant to section 408(d)(3) of FFDCA, 21 U.S.C. 346a(d)(3), announcing the filing of a pesticide petition (PP 4F6873) by Nichino America, Inc., Linden Park, Suite 501, 4550 New Linden Hill Road, Wilmington, DE 19808. The petition requested that 40 CFR 180.511 be amended by establishing increased tolerances for residues of buprofezin (2-[(1,1-dimethylethyl)imino]tetrahydro-3-(1- methylethyl)-5-phenyl-4H-1,3,5-thiadiazin-4-one) in or on the following agricultural commodities: Fruit, citrus, Group 10 at 2.5 ppm); citrus, dried pulp at 7.5 ppm; and citrus, oil at 80 ppm.
In the Federal Register of December 23, 2004 (69 FR 76942) (FRL- 7694-1), EPA issued a notice pursuant to section 408(d)(3) of FFDCA, 21 U.S.C. 346a(d)(3), announcing the filing of a pesticide petition (PP 4F6887) by Nichino America, Inc., Linden Park, Suite 501, 4550 New Linden Hill Road, Wilmington, DE 19808. The petition requested that 40 CFR 180.511 be amended by establishing tolerances for residues of buprofezin (2-[(1,1-dimethylethyl)imino]tetrahydro-3-(1-methylethyl)-5- phenyl-4H-1,3,5-thiadiazin-4-one) in or on the following raw agricultural commodities: Head lettuce at 5 ppm, leaf lettuce at 13 ppm, and Vegetables, cucurbits, group 9 at 0.5 ppm.
Each respective notice included a summary of the petition prepared by the registrant Nichino America, Incorporated, 4550 New Linden Hill Road, Suite 501, Wilmington, DE 19808, or the previous, registrant Aventis CropScience.
A private citizen responded to petitions PP 3E6636, 3E6741, 3E6747, 4F6873, and 4F6887. The substantive public comments and corresponding Agency responses are addressed in a separate document available in the docket for this action under Docket identification (ID) number OPP- 2004-0362.
Section 408(b)(2)(A)(i) of FFDCA allows EPA to establish a tolerance (the legal limit for a pesticide chemical residue in or on a food) only if EPA determines that the tolerance is ``safe.'' Section 408(b)(2)(A)(ii) of FFDCA defines ``safe'' to mean that ``there is a reasonable certainty that no harm will result from aggregate exposure to the pesticide chemical residue, including all anticipated dietary exposures and all other exposures for which there is reliable information.'' This includes exposure through drinking water and in residential settings, but does not include occupational exposure. Section 408(b)(2)(C) of FFDCA requires EPA to give special consideration to exposure of infants and children to the pesticide chemical residue in establishing a tolerance and to ``ensure that there is a reasonable certainty that no harm will result to infants and children from aggregate exposure to the pesticide chemical residue. . . .''
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 of FFDCA 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).
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Aggregate Risk Assessment and Determination of Safety
Consistent with section 408(b)(2)(D) of FFDCA, EPA has reviewed the available scientific data and other relevant information in support of this action. EPA has sufficient data to assess the hazards of and to make a determination on aggregate exposure, consistent with section 408(b)(2) of FFDCA, for a tolerance for residues of buprofezin in or on avocado, papaya, star apple, black sapote, mango, sapodilla, canistel, mamey sapote, sugar apple, cherimoya, atemoya, custard apple, ilama, soursop, birida, guava, feijoa, jaboticaba, wax jambu, starfruit, passionfruit, and acerola at 0.30 parts per million (ppm); pome fruit at 4.0 ppm; peach at 9.0 ppm, meat (cattle, goat, hog, horse, and sheep) at 0.05 ppm; kidney (cattle, goat, hog, horse, and sheep) at 0.05 ppm; Lettuce, head at 5.0 ppm, Lettuce, leaf at 13 ppm; Vegetable, cucurbit group 9 at 0.50 ppm; Fruit, citrus, Group 10 at 2.5 parts per million (ppm); Citrus, dried pulp at 7.5 ppm, and citrus, oil at 80 ppm.
EPA's assessment of exposures and risks associated with establishing the tolerance follows:
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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 buprofezin as well as the no observed adverse effect level (NOAEL) and the lowest observed adverse effect level (LOAEL) from the toxicity studies reviewed are discussed in the Federal Register of June 25, 2003 (68 FR 37765) (FRL- 7310-7).
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Toxicological Endpoints
The dose at which no adverse effects are observed (the NOAEL) from the toxicology study identified as appropriate for use in risk assessment is used to estimate the toxicological level of concern (LOC). However, the lowest dose at which adverse effects of concern are identified (the LOAEL) is sometimes used for risk assessment if no NOAEL was achieved in the toxicology study selected. An uncertainty factor (UF) is applied to reflect uncertainties inherent in the extrapolation from laboratory
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animal data to humans and in the variations in sensitivity among members of the human population as well as other unknowns. An UF of 100 is routinely used, 10X to account for interspecies differences and 10X for intraspecies differences.
Three other types of safety or uncertainty factors may be used: ``Traditional uncertainty factors;'' the ``special FQPA safety factor;'' and the ``default FQPA safety factor.'' By the term ``traditional uncertainty factor,'' EPA is referring to those additional uncertainty factors used prior to FQPA passage to account for database deficiencies. These traditional uncertainty factors have been incorporated by the FQPA into the additional safety factor for the protection of infants and children. The term ``special FQPA safety factor'' refers to those safety factors that are deemed necessary for the protection of infants and children primarily as a result of the FQPA. The ``default FQPA safety factor'' is the additional 10X safety factor that is mandated by the statute unless it is decided that there are reliable data to choose a different additional factor (potentially a traditional uncertainty factor or a special FQPA safety factor).
For dietary risk assessment (other than cancer) the Agency uses the UF to calculate an acute or chronic reference dose (acute RfD or chronic RfD) where the RfD is equal to the NOAEL divided by an UF of 100 to account for interspecies and intraspecies differences and any traditional uncertainty factors deemed appropriate (RfD = NOAEL/UF). Where a special FQPA safety factor or the default FQPA safety factor is used, this additional factor is applied to the RfD by dividing the RfD by such additional factor. The acute or chronic Population Adjusted Dose (aPAD or cPAD) is a modification of the RfD to accommodate this type of safety factor.
For non-dietary risk assessments (other than cancer) the UF is used to determine the LOC. For example, when 100 is the appropriate UF (10X to account for interspecies differences and 10X for intraspecies differences) the LOC is 100. To estimate risk, a ratio of the NOAEL to exposures (margin of exposure (MOE) = NOAEL/exposure) is calculated and compared to the LOC.
The linear default risk methodology (Q*) is the primary method currently used by the Agency to quantify carcinogenic risk. The Q* approach assumes that any amount of exposure will lead to some degree of cancer risk. A Q* is calculated and used to estimate risk which represents a probability of occurrence of additional cancer cases (e.g., risk). An example of how such a probability risk is expressed would be to describe the risk as one in one hundred thousand (1 X 10-5), one in a million (1 X 10-6), or one in ten million (1 X 10-7). Under certain specific circumstances, MOE calculations will be used for the carcinogenic risk assessment. In this non-linear approach, a ``point of departure'' is identified below which carcinogenic effects are not expected. The point of departure is typically a NOAEL based on an endpoint related to cancer effects though it may be a different value derived from the dose response curve. To estimate risk, a ratio of the point of departure to exposure (MOEcancer= point of departure/exposures) is calculated.
A summary of the toxicological endpoints for buprofezin used for human risk assessment is discussed in Unit III.B. of the final rule published in the Federal Register of June 25, 2003 (68 FR 37765) (FRL- 7310-7).
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Exposure Assessment
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Dietary exposure from food and feed uses. Tolerances have been established (40 CFR 180.511) for the residues of buprofezin, in or on a variety of raw agricultural commodities. Tolerances for residues of buprofezin are currently established for ruminant fat, meat byproducts, and liver at 0.05 ppm (40 CFR 180.511). Tolerances are being established for meat (cattle, goat, hog, horse, and sheep) at 0.05 ppm; and kidney (cattle, goat, hog, horse, and sheep) at 0.05 ppm; based on additional animal metabolism studies provided from Nichino America, Inc. Risk assessments were conducted by EPA to assess dietary exposures from buprofezin in food as follows:
i. Acute and chronic exposure. 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.
In conducting the acute dietary risk assessment EPA used the Dietary Exposure Evaluation Model software with the Food Commodity Intake Database (DEEM-FCID\TM\) (ver. 1.30) and Lifeline\TM\ (ver. 2.00) models, which incorporates food consumption data as reported by respondents in the USDA 1994-1996 and 1998 Nationwide Continuing Surveys of Food Intake by Individuals (CSFII), and accumulated exposure to the chemical for each commodity. The following assumptions were made for the acute exposure assessments: The acute analysis assumed tolerance level residues, 100% crop treated for all uses, and DEEM\TM\ (ver. 7.76) default processing factors for all registered/proposed commodities (Tier 1). The chronic analysis assumed DEEM\TM\ (ver.7.76) default processing factors for all registered/proposed commodities and incorporated percent crop treated estimates and average field trial residues.
ii. Cancer. In accordance with the EPA Guidelines for Carcinogen Risk Assessment, the Carcinogen Assessment Review Commission classified buprofezin as having ``suggestive evidence of carcinogenicity, but not sufficient to assess human carcinogenic potential'' based on liver tumors in female mice. The Committee further recommended no quantification of cancer risk.
iii. Anticipated residue and percent crop treated (PCT) information. Section 408(b)(2)(F) of FFDCA states that the Agency may use data on the actual percent of food treated for assessing chronic dietary risk only if the Agency can make the following findings: Condition 1, 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; Condition 2, that the exposure estimate does not underestimate exposure for any significant subpopulation group; and Condition 3, 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 section 408(b)(2)(F) of FFDCA, EPA may require registrants to submit data on PCT.
The Agency used PCT information as follows:
5% crop treated (PCT) for cantaloupes;
2.5% crop treated for cotton, grapefruit, grapes, lemons, limes, oranges, squash, tangelos, tangerines, tomatoes, and watermelon;
Market share % crop treated was projected not to exceed 5% for apples, and 13% for peaches;
All other crops currently registered and/or proposed commodities were assumed to be 100% crop treated.
The Agency believes that the three conditions listed in Unit C. 1. iii. have been met. With respect to Condition 1, PCT estimates are derived from Federal and private market survey data, which are reliable and have a valid basis. For previously registered crops, EPA used an average of the values from these surveys over the last 5 years for estimating PCT for chronic dietary
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exposure assessments. For most newly registered crops, the Agency assumed 100% PCT. In estimating PCT for the apples and peaches as newly-registered crops, EPA assumed that the PCT for buprofezin would at least equal or exceed the PCT for the leading comparable insect growth regulatory pesticide alternative on that crop. For peaches, PCT for buprofezin was projected to potentially exceed the leading alternative's PCT by a factor of five because buprofezin has a slight cost advantage over the alternative on that crop. With regards to apples, buprofezin was projected to slightly exceed sales of the leading alternative's PCT because buprofezin is an excellent technical fit as an insect pest management (IPM) insecticide for apples. The Agency is reasonably certain that the percentage of the food treated is not likely to be an underestimation.
As to Conditions 2 and 3, regional consumption information and consumption information for significant subpopulations is taken into account through EPA's computer-based model for evaluating the exposure of significant subpopulations including several regional groups. Use of this consumption information in EPA's risk assessment process ensures that EPA's exposure estimate does not understate exposure for any significant subpopulation group and allows the Agency to be reasonably certain that no regional population is exposed to residue levels higher than those estimated by the Agency. Other than the data available through national food consumption surveys, EPA does not have available information on the regional consumption of food to which buprofezin may be applied in a particular area.
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Dietary exposure from drinking water. The Agency lacks sufficient monitoring exposure data to complete a comprehensive dietary exposure analysis and risk assessment for buprofezin in drinking water. Because the Agency does not have comprehensive monitoring data, drinking water concentration estimates are made by reliance on simulation or modeling taking into account data on the physical characteristics of buprofezin.
The Agency uses the Generic Estimated Environmental Concentration (GENEEC) or the Pesticide Root Zone Model/Exposure Analysis Modeling System (PRZM/EXAMS) to estimate pesticide concentrations in surface water and Screening Concentrations in Groundwater (SCI-GROW), which predicts pesticide concentrations in ground water. In general, EPA will use GENEEC (a Tier 1 model) before using PRZM/EXAMS (a Tier 2 model) for a screening-level assessment for surface water. The GENEEC model is a subset of the PRZM/EXAMS model that uses a specific high-end runoff scenario for pesticides. GENEEC incorporates a farm pond scenario, while PRZM/EXAMS incorporate an index reservoir environment in place of the previous pond scenario. The PRZM/EXAMS model includes a percent crop area factor as an adjustment to account for the maximum percent crop coverage within a watershed or drainage basin.
None of these models include consideration of the impact processing (mixing, dilution, or treatment) of raw water for distribution as drinking water would likely have on the removal of pesticides from the source water. The primary use of these models by the Agency at this stage is to provide a screen for sorting out pesticides for which it is unlikely that drinking water concentrations would exceed human health levels of concern.
Since the models used are considered to be screening tools in the risk assessment process, the Agency does not use estimated environmental concentrations (EECs), which are the model estimates of a pesticide's concentration in water. EECs derived from these models are used to quantify drinking water exposure and risk as a %RfD or %PAD. Instead drinking water levels of comparison (DWLOCs) are calculated and used as a point of comparison against the model estimates of a pesticide's concentration in water. DWLOCs are theoretical upper limits on a pesticide's concentration in drinking water in light of total aggregate exposure to a pesticide in food, and from residential uses. Since DWLOCs address total aggregate exposure to buprofezin they are further discussed in the aggregate risk sections in Unit E.
Based on the GENEEC, PRZM/EXAMS and SCI-GROW models, the EECs of buprofezin for acute exposures are estimated to be 19.2 parts per billion (ppb) for surface water and 0.1 ppb for ground water. The EECs for chronic exposures are estimated to be 4.5 ppb for surface water and 0.1 ppb for ground water.
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From non-dietary exposure. The term ``residential exposure'' is used in this document to refer to non-occupational, non-dietary exposure (e.g., for lawn and garden pest control, indoor pest control, termiticides, and flea and tick control on pets). Buprofezin is not registered for use on any sites that would result in residential exposure.
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Cumulative effects from substances with a common mechanism of toxicity. Section 408(b)(2)(D)(v) of FFDCA requires that, when considering whether to establish, modify, or revoke a tolerance, the Agency consider ``available information'' concerning the cumulative effects of a particular pesticide's residues and ``other substances that have a common mechanism of toxicity.''
Unlike other pesticides for which EPA has followed a cumulative risk approach based on a common mechanism of toxicity, EPA has not made a common mechanism of toxicity finding as to buprofezin and any other substances and buprofezin does not appear to produce a toxic metabolite produced by other substances. For the purposes of this tolerance action, therefore, EPA has not assumed that buprofezin has a common mechanism of toxicity with other substances. For information regarding EPA's efforts to determine which chemicals have a common mechanism of toxicity and to evaluate the cumulative effects of such chemicals, see the policy statements released by EPA's OPP concerning common mechanism determinations and procedures for cumulating effects from substances found to have a common mechanism on EPA's web site at http://www.epa.gov/pesticides/cumulative/ .
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Safety Factor for Infants and Children
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In general. Section 408 of FFDCA provides that EPA shall apply an additional tenfold margin of safety for infants and children in the case of threshold effects to account for prenatal and postnatal toxicity and the completeness of the data base on toxicity and exposure unless EPA determines based on reliable data that a different margin of safety will be safe for infants and children. Margins of safety are incorporated into EPA risk assessments either directly through use of a MOE analysis or through using uncertainty (safety) factors in calculating a dose level that poses no appreciable risk to humans. In applying this provision, EPA either retains the default value of 10X when reliable data do not support the choice of a different factor, or, if reliable data are available, EPA uses a different additional safety factor value based on the use of traditional uncertainty factors and/or special FQPA safety factors, as appropriate.
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Prenatal and postnatal sensitivity. The Agency concluded that the available studies provided no indication of increased susceptibility of rats or
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rabbits following in utero exposure or of rats following prenatal/ postnatal exposure to buprofezin.
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Conclusion. There is a complete toxicity data base for buprofezin and exposure data are complete or are estimated based on data that reasonably accounts for potential exposures. EPA determined that the 10X SF to protect infants and children should be reduced to 1X.
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Aggregate Risks and Determination of Safety
To estimate total aggregate exposure to a pesticide from food, drinking water, and residential uses, the Agency calculates DWLOCs which are used as a point of comparison against EECs. DWLOC values are not regulatory standards for drinking water. DWLOCs are theoretical upper limits on a pesticide's concentration in drinking water in light of total aggregate exposure to a pesticide in food and residential uses. In calculating a DWLOC, the Agency determines how much of the acceptable exposure (i.e., the PAD) is available for exposure through drinking water (e.g., allowable chronic water exposure (mg/kg/day) = cPAD - (average food + residential exposure). This allowable exposure through drinking water is used to calculate a DWLOC.
A DWLOC will vary depending on the toxic endpoint, drinking water consumption, and body weights. Default body weights and consumption values as used by the EPA's Office of Water are used to calculate DWLOCs: 2 Liter (L)/70 kg (adult male), 2L/60 kg (adult female), and 1L/10 kg (child). Default body weights and drinking water consumption values vary on an individual basis. This variation will be taken into account in more refined screening-level and quantitative drinking water exposure assessments. Different populations will have different DWLOCs. Generally, a DWLOC is calculated for each type of risk assessment used: Acute, short-term, intermediate-term, chronic, and cancer.
When EECs for surface water and ground water are less than the calculated DWLOCs, OPP concludes with reasonable certainty that exposures to the pesticide in drinking water (when considered along with other sources of exposure for which OPP has reliable data) would not result in unacceptable levels of aggregate human health risk at this time. Because OPP considers the aggregate risk resulting from multiple exposure pathways associated with a pesticide's uses, levels of comparison in drinking water may vary as those uses change. If new uses are added in the future, OPP will reassess the potential impacts of residues of the pesticide in drinking water as a part of the aggregate risk assessment process.
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Acute risk. Using the exposure assumptions discussed in this unit for acute exposure, the acute dietary exposure from food to buprofezin will occupy 5.0% of the aPAD for females 13 to 19 years old. In addition, there is potential for acute dietary exposure to buprofezin] in drinking water. After calculating DWLOCs and comparing them to the EECs for surface water and ground water, EPA does not expect the aggregate exposure to exceed 100% of the aPAD, as shown in Table 1 of this unit:
Table 1.--Aggregate Risk Assessment for Acute Exposure to Buprofezin
Surface Ground Population Subgroup
aPAD (mg/ % aPAD Water EEC Water EEC Acute DWLOC kg)
(Food) (ppb)
(ppb)
(ppb)
Females (13-49 years old)
2.0
5
19.2
0.1 57,000
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Chronic risk. Using the exposure assumptions described in this unit for chronic exposure, the chronic aggregate risk assessment takes into account average exposure estimates from dietary consumption of buprofezin (food and drinking water). However, there are no residential uses for buprofezin that result in chronic residential exposure to buprofezin. Therefore, the chronic aggregate risk assessment will consider exposure from food and drinking water only. There is potential for chronic dietary exposure to buprofezin in drinking water. After calculating DWLOCs and comparing them to the EECs for surface water and ground water, EPA does not expect the aggregate exposure to exceed 100% of the cPAD, as shown in Table 2 of this unit:
Table 2.--Aggregate Risk Assessment for Chronic (Non-Cancer) Exposure to Buprofezin
Surface Ground Population Subgroup
cPAD mg/kg/ %cPAD Water EEC Water EEC Chronic day
(Food) (ppb)
(ppb) DWLOC (ppb)
U.S. population
0.01
38
4.5
0.1
220
All infants (
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