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Cryolite: Pesticide Tolerance Petition |
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Cryolite: Pesticide Tolerance Petition [Federal Register: August 7, 1997 (Volume 62, Number 152)]
SUMMARY: This notice
announces the filing of a pesticide petition proposing regulations
amending the established tolerances for residues of the insecticidal
fluorine compounds cryolite and/or synthetic cryolite (sodium aluminum
fluoride or sodium aluminofluoride) in or on cabbage, citrus fruits,
collards, eggplant, lettuce, peaches, and tomatoes; and establishing
tolerances for the processed foods, raisins and tomato paste. This
notice includes a summary of the petition that was prepared by the
petitioner, The Cryolite Task Force. ADDRESSES: By mail submit written comments to:
Public Information and Records Integrity Branch, Information Resources
and Services Division (7506C), Office of Pesticide Programs, Environmental
Protection Agency, 401 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. (1) Increasing the established tolerances for residues of the insecticidal fluorine compounds cryolite and /or synthetic cryolite in or on the agricultural commodities as listed below; (2) establishing separate tolerances for the residues in or on head and leaf lettuce; and (3) establishing tolerances for the residues in the processed foods,
raisins at 55 ppm, and tomato paste at 45 ppm. Commodity Current Proposed cabbage 7 ppm 45 ppm EPA has determined that the petition contains 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. As required by section 408(d) of the FFDCA, as recently amended by the Food Quality Protection Act, The Cryolite Task Force 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 The Cryolite Task force; 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 purposes of clarity. 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-750 (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 Empirical Formula: Na3AlF6 A Reregistration Eligibility Decision (RED) was issued for cryolite in August 1996. As documented in the RED, the Agency has determined that plant residues are inorganic surface residues of cryolite, measured as total fluoride; and that the residue of concern in animals also is total fluoride. Provisions in the FQPA which are relevant to degradates or metabolites of pesticide chemical residues are not applicable to elemental fluorine. Magnitude of the residue in plants. Residue data covering all of the uses associated with the RAC tolerances requested by this petition have been reviewed and approved by the Agency (see the Cryolite RED, pages 19 - 26). The proposed tolerance amendments are summarized, below: Lettuce (head) - 180 ppm 2. Magnitude of the residue in processed food/feed. As documented in the RED, EPA has concluded that acceptable processing studies support the proposed tolerances of 45 ppm for tomato paste and 55 ppm for raisins. 3. Directions for use. Use directions consistent with the proposed revised RAC and new processed food tolerances have been approved by the Agency. Labeling was approved by EPA for the Gowan registration (10163-41) on May 10, 1995. Labeling was approved for the Atochem registration (4581-116) on October 26, 1995. 4. Analytical method. EPA concluded in the cryolite RED that adequate methodology is available for data collection and tolerance enforcement. Methods for both plant residues and animal tissues have undergone successful Agency validation and will be published in the Pesticide Analytical Manual, Vol. II. Using these methods, total fluoride is determined using a pH/ion meter with a fluoride-specific electrode. The limit of quantitation is 0.05 ppm. The residue analytical method does not distinguish between naturally occuring fluoride and fluoride resulting from agricultural use of cryolite. Current FDA multi-residue screening protocols are not appropriate for inorganic fluoride residues. 5. Practical methods for removing residues. Plant residues are inorganic surface residues of cryolite. Data reviewed by EPA for the RED show that washing, peeling, and trimming are effective methods of removing these residues. 6. Plant metabolism. EPA concluded in the cryolite RED that the qualitative nature of the residue in plants is understood and that plant residues are inorganic surface residues of cryolite which are measured as fluoride. 7. Animal metabolism. EPA concluded in the cryolite RED that cryolite metabolism in animals manifests itself as free fluoride, that the qualitative nature of the residue is understood and that total fluoride is the residue of concern. 8. Magnitude of the residue in meat, milk, poultry and eggs. EPA
concluded in the cryolite RED that there is no reasonable expectation
of finite fluoride residues in ruminant or poultry tissues as a
result of livestock ingestion of cryolite. 1. Acute toxicity. A rat acute oral toxicity study (MRID 00138096) showed an LD50 greater than 5,000 milligrams/kilograms (mg/kg). A rabbit acute dermal toxicity study (MRID 00128107) demonstrated an LD50 of 2,100 mg/kg. An LC50 > 2.06 mg/L and <5.03 mg/L was seen in an acute inhalation study with rats (MRID 00128107). Technical cryolite is a moderate eye irritant in rabbits (MRID 00128106). Cryolite is not a skin irritant to rabbits (MRID 00128106) and is not a dermal sensitizer to guinea pigs (MRID 00138097). 2. Subchronic toxicity. Cryolite was tested in a 28-day range- finding feeding study in rats (MRID 00128109) at dose levels of 0, 250, 500, 1,000, 2,000, 4,000, 10,000, 25,000 and 50,000 ppm in the diet (representing approximately 0, 25, 50, 100, 200, 400, 1,000, 2,500 and 5,000 mg/kg/day). The only compound related effect seen in this study was a change in coloration and physical property of the teeth. A no observed effect level (NOEL) was not determined in this study. The lowest observed effect level (LOEL) is 250 ppm (25 mg/kg/day) based on dental fluorosis. In a 90-day rat feeding study (MRID 00158000), cryolite was tested at dose levels of 0, 50, 5,000 and 50,000 ppm (corresponding to 0, 3.8, 399.2, and 4,172.3 mg/kg/day in males and 0, 4.5, 455.9 and 4,758.1 mg/kg/day in females). The NOEL was 50 ppm (3.8 mg/kg/day) for effects other than fluoride accumulation. The LOEL was 5,000 ppm (399.2 mg/kg/day) based on lesions observed in the stomach. Fluoride accumulated at all dose levels in this study. Cryolite was tested in a 90-day dog feeding study (MRID 00157999) at dose levels of 0, 500, 10,000, and 50,000 ppm (corresponding to 0, 17, 368, and 1,692 mg/kg/day). The NOEL was 10,000 ppm (368 mg/kg/day). The LOEL was 50,000 ppm (1,692 mg/kg/day) for effects other than fluoride accumulation. Fluoride accumulation occurred at all dose levels. A 21-day subchronic dermal toxicity study in rabbits (MRID 41224801) is considered invalid because it is likely that cryolite was ingested by the test animals during the study. For this reason, the systemic dermal NOEL and LOEL could not be determined from this study. EPA noted in the RED that an additional subchronic dermal study is not necessary, because based on its chemical/physical properties, cryolite would not be absorbed through the skin to any appreciable extent. 3. Genotoxicity. Cryolite was negative in an Ames reverse mutation
test (MRID 41838401) using Salmonella typhimurium with and without
activation at dose levels of 167, 500, 1,670, 5,000, 7,500 and 10,000
g/plate. Cryolite was tested in an in vitro chromosome aberration
assay (MRID 41838402) using human lymphocytes at 100, 500, and 1,000
g/ml, with and without activation. The results were negative. Cryolite
also was negative in an unscheduled DNA synthesis study (MRID 41838403)
with rat hepatocytes 4. Chronic toxicity. The Agency concluded in the cryolite RED that the available information does not support the regulation of cryolite insecticides as carcinogens. EPA has classified cryolite as a Group ``D'' chemical (not classifiable as to human carcinogenicity.'' Further, EPA has noted that fluoride has been the subject of a comprehensive review by the National Research Council (National Academy of Sciences Subcommittee of Health Effects of Ingested Fluoride) who concluded that ``. . . the available laboratory data are insufficient to demonstrate a carcinogenic effect of fluoride in animals'' and that ``. . .the weight of evidence from more that 50 epidemiological studies does not support the hypothesis of an association between fluoride exposure and increased cancer risk in humans.'' As stated in the Federal Register of May 8, 1996, and reiterated in the cryolite RED, the Agency is in agreement with the conclusions reached by the National Academy of Science (NAS). The following specific chronic/oncogenicity studies are included in the cryolite toxicology data base: A 2-year bioassay in B6C3F1 mice (HED DOC No. 009682) was conducted by the National Toxicology Program (NTP) using sodium fluoride as the test material at dose levels of 0, 25, 100, and 175 ppm, in water, representing 0, 2.4, 9.6, and 16.7 mg/kg/day in males and 0, 2.8, 11.3, and 18.8 mg/kg/day in females. The NOEL was less than 25 ppm (2.4 mg/kg/day). The LOEL was 25 ppm (2.4 mg/kg/day) based on attrition of the teeth in males, discoloration and mottling of the teeth in males and females and increased bone fluoride in both sexes. NTP considered that there was ``no evidence'' of carcinogenic activity in male and female mice. A 2-year bioassay in F344/N rats (HED DOC No. 009682) also was conducted by the National Toxicology Program (NTP) using sodium fluoride as the test material at dose levels of 0, 25, 100, and 175 ppm, in water, representing 0, 1.3, 5.2 and 8.6 mg/kg/day in males and 0, 1.3, 5.5 and 9.5 mg/kg/day in females. Osteosarcoma of the bone was observed only in one male of fifty (1/50) in the 100 ppm group and in three of eighty (3/80) males in the 175 ppm group. The NOEL was less than 25 ppm (1.3 mg/kg/day). The LOEL was 25 ppm (1.3 mg/kg/day) based on mottling of teeth, dentine incisor dysplasia, increased serum, urine and bone fluoride levels in males and females and incisor odontoblast and incisor ameloblast degeneration in males. NTP considered that there was ``equivocal evidence'' of carcinogenic activity in male rats in this study and ``no evidence'' of carcinogenic activity in female rats. EPA concluded in the cryolite RED that the NTP studies utilizing sodium fluoride in lieu of cryolite satisfy the guideline study requirements for both the rodent chronic feeding study and the rat carcinogenicity study. Fluoride has been identified as the residue of toxicological concern in cryolite and synthetic cryolite and these compounds act as free fluoride. It may be noted that the NTP studies, which utilized freely soluble NaF represent a ``worst-case'' toxicological scenario on a ppm basis compared to what would be expected with cryolite per se, from which fluoride ion dissociation is much more limited. A 1-year chronic dog feeding study (MRID 42575101) was conducted with cryolite at dose levels of 0, 3,000, 10,000, and 30,000 ppm, representing 0, 95, 366, and 1,137 mg/kg/day in males and 0, 105, 387, and 1,139 mg/kg/day in females (in terms of fluoride the doses are 0, 51, 198, and 614 mg F/kg/day for males and 0, 57, 209, and 615 mg F/kg/day for females). The NOEL was less than 3,000 ppm (95 mg/kg/day in males and 105 mg/kg/day in females). The LOEL was 3,000 ppm based on increases in emesis, nucleated cells in males, renal lesions and a decrease in urine specific gravity in females. 5. Reproductive toxicity. A two-generation rat reproduction study (MRID 43387501) was conducted with cryolite at dietary dose levels of 0, 200, 600, and 1,800 ppm (representing 0, 14, 42, and 128 mg/kg/day for males and 0, 16, 49, and 149 mg/kg/day for females, respectively, during premating). The systemic toxicity NOEL was not determined. The LOEL for systemic toxicity was 200 ppm (15 mg/kg/day) based on dental fluorosis. The NOEL and LOEL for reproductive toxicity were 600 and 1,800 ppm, respectively (46 and 138 mg/kg/day) based on decreased pup body weights. The National Research Council (NRC) has reviewed the potential
for reproductive effects from fluoride per se. In the report Health
Effects of Ingested Fluoride, the NRC concluded that: A range-finding developmental toxicity study in female rabbits (MRID 42297901) tested cryolite at dose levels of 0, 10, 30, 100, 300, and 1,000 mg/kg/day (gavage). The NOEL for maternal toxicity was determined to be 10 mg/kg/day and the LOEL was 30 mg/kg/day based on an increased incidence of soft stool and dark colored feces and decreased defecation and urination. The NOEL for developmental toxicity was 30 mg/kg/day. The developmental LOEL could not be assessed due to excessive maternal toxicity at dose levels of 30 mg/kg/day. 7. Metabolism/metabolite toxicity. As noted in the RED, cryolite behaves toxicologically as free fluoride. That is, dissociation produces free fluoride ions which are assimilated into bone. There are numerous references in the open literature concerning the metabolism of cryolite and other fluoride salts. The National Research Council concluded in their 1993 comprehensive report entitled Health Effects of Ingested Fluoride that fluoride is readily absorbed by the gut and rapidly becomes associated with teeth and bones. The remaining fluoride is eliminated almost exclusively by the kidneys with the rate of renal clearance related directly to urinary pH. 8. Endocrine effects. The two-generation rat reproduction study,
the developmental toxicity studies in rats, rabbits and mice and
the dog chronic study summarized above did not 2. Dietary exposure-drinking water. In the Environmental Fate Assessment conducted for the RED, the Agency concluded that the use of cryolite should have negligible impacts on fluoride levels in ground and surface water. For this reason, the contribution of cryolite to potential exposure to fluoride from drinking water need not be considered in the aggregate risk assessment. However, fluoride is intentionally supplemented to drinking water for prevention of dental caries and may also be present at natural background levels. The U.S. Public Health Service recommends an optimal fluoride concentration of 0.7 - 1.2 mg/L to prevent dental caries and minimize dental fluorosis. Fluoride levels in public drinking water are regulated under the Safe Drinking Water Act. A Maximum Concentration Limit (MCL) of 4.0 mg/L (0.114 mg/kg/day) has been established. EPA has estimated previously that levels of fluoride in/on food from the agricultural use of cryolite plus fluoride levels in U.S. drinking water supplies results in a daily dietary intake of fluoride of approximately 0.095 mg/kg/day. This is substantially less than the Maximum Concentration Limit (MCL) of 4.0 mg/L (0.144 mg/kg/day), a level which provides no known or anticipated adverse health effect as determined by the Surgeon General. As noted in the RED, the Agency has concurred with the findings of the Surgeon General that adverse health effects have not been found in the U. S. population below 8 mg F/L (0.23 mg/kg/day). 3. Non-dietary exposure. Cryolite is used almost exclusively as an agricultural crop protection insecticide. Conceivably, cryolite also could be used in outdoor homeowner/residential sites for insect control in ornamentals and shade trees. Cryolite is not registered for either lawn or crack and crevice treatments. EPA concluded in the RED that a post-application exposure assessment for cryolite (including both occupational and residential exposure) was not appropriate since no toxicological endpoints relevant to non-dietary exposure have been identified for cryolite. The Task Force concludes that non-dietary exposure represents a
negligible component of potential aggregate exposure to cryolite
and need not be considered in the aggregate risk assessment. |
ENVIRONMENTAL PROTECTION AGENCY
Fluoride Action Network | 802-338-5577 | info@fluoridealert.org |