[Federal Register Volume 62, Number 48 (Wednesday, March 12, 1997)]
[Notices]
[Pages 11437-11441]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-6015]
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ENVIRONMENTAL PROTECTION AGENCY
[PF-712; FRL-5587-7]
The Cryolite Task Force; Pesticide Tolerance Petition Filing
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of filing.
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SUMMARY: This notice announces the filing of a pesticide petition
proposing regulations establishing tolerances for residues of the
insecticidal fluorine compounds cryolite and/or synthetic cryolite
(sodium aluminum fluoride or sodium aluminofluoride) in or on potatoes
and in processed potato waste. This notice includes a summary of the
petition that was prepared by the petitioner, The Cryolite Task Force.
DATES: Comments, identified by the docket control number [PF-712] must
be received on or before April 11, 1997.
ADDRESSES: By mail, submit written comments to: Public Response and
Program Resources Branch, Field Operations 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 22202.
Comments and data may also be submitted electronically by sending
electronic mail (e-mail) to: opp-docket@epamail.epa.gov. Electronic
comments must be submitted either in ASCII format (avoiding the use of
special characters and any form of encryption) or in WordPerfect in 5.1
file format. All comments and data in electronic form must be
identified by the docket control number [PF-712]. Electronic comments
on this notice may be filed online at many Federal Depository
Libraries. The official record for this rulemaking, as well as the
public version described above, will be kept in paper form. Additional
information on electronic submissions can be found in Unit II. of this
document.
Information submitted as a comment concerning this notice may be
claimed confidential by marking any part or all of that information as
``Confidential Business Information'' (CBI). Information so marked will
not be
[[Page 11438]]
disclosed except in accordance with procedures set forth in 40 CFR part
2. No CBI should be submitted through e-mail. 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.
FOR FURTHER INFORMATION CONTACT: William Jacobs, Acting, Product
Manager 14, Registration Division, Office of Pesticide Programs,
Environmental Protection Agency, 401 M St., SW., Washington, DC 20460.
Office location, telephone number, and e-mail address: Rm. 219, CM #2,
1921 Jefferson Davis Highway, Arlington, VA 22202. (703) 305-6600; e-
mail: jacobs.william@epamail.epa.gov.
SUPPLEMENTARY INFORMATION: EPA has received a pesticide petition from
The Cryolite Task Force c/o Gowan, P.O. Box 5568, Yuma, AZ 85366. The
petition proposes, pursuant to section 408 of the Federal Food, Drug,
and Cosmetic Act (FFDCA), 21 U.S.C. 346a, to amend 40 CFR 180.145 to
renew the regulations that established tolerances for the insecticidal
fluorine compounds cryolite and/or synthetic cryolite in or on potatoes
at 2.0 parts per million (ppm) and processed potato waste at 22 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 (FQPA) (Pub. L. 104-170), 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.
I. The Cryolite Task Force's Petition Summary
This petition is submitted by the Cryolite Task Force (Consortium
No. 62569), under section 408 of the FFDCA, as most recently amended by
the FQPA.
This submission amends petitions PP 9F3739 and FAP 1H5604 by
providing the additional information specified by the FQPA. A permanent
tolerance is proposed for residues of the insecticide sodium
aluminofluoride (cryolite and/or synthetic cryolite) in or on the raw
agricultural commodities (RAC) potatoes, as provided by the new FFDCA
section 408. In addition, the petitioner proposes that EPA establish a
permanent tolerance for residues of cryolite in processed potato waste,
as provided under the new FFDCA section 408.
Time-limited tolerances for residues of sodium aluminofluoride
(cryolite and/or synthetic cryolite) in/on potatoes and processed
potato waste were initially granted on May 5, 1993. These tolerances
expired on May 6, 1996. A time limitation was required initially for
these regulations because a chronic dog feeding study and a two-
generation rat reproduction study were outstanding. These two studies
were submitted and were found acceptable in reviews dated April 13,
1994 (chronic dog) and February 24, 1995 (rat reproduction). In the
Federal Register of May 8, 1996 (61 FR 20781) (FRL-5362-6), EPA
proposed establishing permanent tolerances of 2 ppm and 22 ppm for
residues of cryolite in/on potatoes and processed potato waste,
respectively. A 30-day comment period was specified by the Agency for
these proposed regulations. However, prior to publication of final
regulations, the FQPA specified additional requirements for tolerance
petitions. This submission amends PP 9F3739 and FAP 1H5604 by providing
the additional information specified.
A. Residue Data
1. Name, identity, and composition of the residue. Cryolite (sodium
aluminofluoride, sodium hexafluoroaluminate or sodium aluminum
fluoride) is a fluorine-containing insecticide which is found in
naturally occurring mineral deposits and also is produced
synthetically.
Empirical Formula: Na3AlF6
Molecular Weight: 209.97
CAS Registry No.: 15096-52-3
OPP Chemical Code: 075101
A Reregistration Eligibility Decision (RED) was issued for cryolite
in August 1996. As documented in the May 8, 1996 Federal Register and
reiterated 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.
2. Magnitude of the residue in plants. As documented in the May 8,
1996 Federal Register and reiterated in the RED, the Agency has
concluded that complete and acceptable crop residue data are available
to support the proposed tolerance of 2 ppm in or on potatoes.
Data previously reviewed by EPA show background levels of fluoride
in untreated potatoes ranging from 0.14 ppm to 0.31 ppm. Levels of
fluoride found in treated potatoes ranged from 0.18 ppm to 0.94 ppm.
3. Magnitude of the residue in processed food/feed. As documented
in the May 8, 1996 Federal Register and reiterated in the RED, EPA has
concluded that an acceptable potato processing study supports the
proposed tolerance of 22 ppm in or on processed potato waste. This
study indicates that cryolite residues concentrated 11x in potato
peels/potato waste processed from potatoes treated at a 6.7x
exaggerated rate. Residues did not concentrate in potato chips, flakes,
or granules.
4. Directions for use. Labeling has been approved for foliar
application to potatoes at up to 11.5 lbs. active ingredient (a.i.) per
acre, with a maximum seasonal application of 92 lbs. a.i. per acre.
5. Analytical method. EPA concluded in the May 8, 1996 Federal
Register and reiterated 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 PAM, 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 occurring
fluoride and fluoride resulting from agricultural use of cryolite.
Current FDA multi-residue screening protocols are not appropriate for
inorganic fluoride residues.
6. Practical methods for removing residues. Plant residues are
inorganic surface residues of cryolite. Data previously submitted in
FAP 1H5604 show that washing and peeling are effective methods of
removing these residues.
7. Plant metabolism. EPA concluded in the May 8, 1996 Federal
Register and reiterated in the cryolite RED that the qualitative nature
of the residue in plants is understood and that plant residues are
inorganic surface residues
[[Page 11439]]
of cryolite which are measured as fluoride.
8. Animal metabolism. EPA concluded in the May 8, 1996 Federal
Register and reiterated 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.
9. Magnitude of the residue in meat, milk, poultry and eggs. EPA
concluded in the May 8, 1996 Federal Register and reiterated 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.
B. Toxicological Data
The cryolite RED concluded that the toxicological data base was
adequate for a reregistration eligibility decision for numerous crop
uses, including potatoes. No additional toxicology requirements were
specified in the RED. The cryolite residue of toxicological concern is
fluoride; and health effects identified for fluoride in humans and
animals are skeletal and dental fluorosis. Dental fluorosis (mottling
of tooth enamel) is not considered to be an adverse effect.
Further, the Agency has determined that although fluoride
accumulation is demonstrated in a number of studies, the accumulation
itself is not considered an adverse effect.
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 at dose levels up to and
including 50 g/ml.
4. Chronic toxicity. The Agency concluded in the May 8, 1996
Federal Register and reiterated in the cryolite RED that the available
information does not support the regulation of cryolite insecticides as
carcinogens. The Agency 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 May 8, 1996 Federal
Register 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 NTP using sodium fluoride as the test material at dose
levels of 0, 25, 47, 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 1 male of 50 (1/
50) in the 100 ppm group and in 3 of 80 (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 May 8, 1996 Federal Register and reiterated 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 should 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.
[[Page 11440]]
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:
There have been reports of adverse effects on reproductive
outcomes associated with high levels of fluoride in many animal
species. In most of the studies, however, the fluoride
concentrations associated with adverse effects were far higher than
those encountered in drinking water. The apparent threshold
concentration for inducing reproductive effects was 100 mg/L in
mice, rats, foxes and cattle; 100-200 mg/L in minks, owls and
kestrels; and over 500 mg/L in hens. Based on these findings, the
subcommittee concludes that the fluoride concentrations associated
with adverse reproductive effects in animals are far higher than
those to which human populations are exposed. Consequently,
ingestion of fluoride at current concentrations should have no
adverse effects on human reproduction.
6. Developmental toxicity. A developmental toxicity study was
performed with cryolite in rats (MRID 00128112) at dose levels of 0,
750, 1,500, and 3,000 mg/kg/day (gavage). The NOEL for both
developmental and maternal toxicity was 3,000 mg/kg/day. At this dose
level, the only observation was whitening of the teeth of dams. A
developmental toxicity study was conducted in female mice (MRID
42297902) with cryolite at dose levels of 0, 30, 100, and 300 mg/kg/day
(gavage). The NOEL for maternal toxicity was 30 mg/kg/day and the LOEL
was 100 mg/kg/day based on a single mortality in this group. Fetuses at
300 mg/kg/day exhibited bent ribs and bent limb bones. The NOEL for
developmental toxicity was 100 mg/kg/day. The LOEL was 300 mg/kg/day
based on an increase in bent ribs and bent limbs. 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 May 8, 1996
Federal Register and reiterated 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 rat, rabbit and mouse developmental studies and the dog chronic
studies summarized above did not demonstrate any effects with cryolite
that are similar to those produced by naturally occurring estrogens, or
other endocrine effects. No endocrine effects were determined in the
rat and mouse NTP studies.
In addition, it should be noted that national and international
regulatory organizations (U.S. EPA Office of Water, U.S. DHHS, the
Canadian Government, and the World Health Organization) have assessed
potential health risks from exposure to fluoride. EPA has concluded
that the endpoints and estimated effect levels documented by these
organizations are similar and that the health effects of fluoride in
animals and humans include dental and skeletal fluorosis. Endocrine
effects have not been recognized as toxicological endpoints for
fluoride by any worldwide regulatory authority.
C. Aggregate Exposure
1. Dietary exposure-food. As noted in the May 8, 1996 Federal
Register and reiterated in the RED, the Agency has estimated dietary
exposure to cryolite using reassessed tolerances for all crops
(including the proposed tolerances for potatoes) and percent of crop
treated assumptions. In the RED, EPA estimated dietary exposure to
cryolite from all crops to be approximately 0.020 mg/kg/day for the
U.S. population, 0.024 mg/kg/day for children 1-6, 0.015 mg/kg/day for
children 7-12, and 0.028 mg/kg/day for nursing females 13+ years. For
the highest exposed subgroup (females 20 years old and over), the
Agency estimated exposure of 0.038 mg/kg/day (61 FR 20781). The Agency
estimated dietary exposure resulting from the specific use of cryolite
on potatoes to be approximately 0.00016 mg/kg/day. The Task Force
believes that these exposure estimates in fact overstate actual dietary
exposure since cryolite tolerance levels, rather than residues actually
present at the consumer level were used by EPA in the exposure
assessments.
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 to 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 previously estimated
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 May 8, 1996 Federal Register and reiterated in the
RED, the Agency has concurred with the findings
[[Page 11441]]
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.
D. Cumulative Effects
The residue of toxicological concern in cryolite is fluoride.
Although fluoride supplements in drinking water are not considered to
be pesticidal substances, the dietary contribution of drinking water to
overall fluoride exposure has been discussed elsewhere in this summary.
Current tolerances for insecticidal fluorine-containing compounds are
limited to cryolite and synthetic cryolite. For this reason,
consideration of potential cumulative effects of residues from
pesticidal substances other than sodium aluminofluoride with a common
mechanism of toxicity are not applicable.
E. Safety Determination
1. U.S. population. As discussed above, non-dietary exposure to
cryolite is negligible. For dietary exposure, EPA has concluded that
rather than establishing a traditional Reference Dose (RfD), a weight-
of-the-evidence risk assessment is a more appropriate approach for
cryolite. The toxicological endpoint of concern for dietary exposure to
cryolite is skeletal fluorosis. EPA has approximated that total dietary
fluoride levels in food plus drinking water is 0.095 mg/kg/day. Of this
total exposure, the dietary (food) contribution is about 0.020 mg/kg/
day for the U.S. population, and 0.038 mg/kg/day for the highest
exposed subgroup (females 20 years old and over). The proposed potato
tolerances have been estimated by EPA to contribute approximately
0.00016 mg/kg/day to total dietary exposure. These exposure estimates
likely overstate actual dietary exposure, since marketbasket residue
levels for cryolite have not been considered. As noted above, the
Agency has concurred with the findings of the Surgeon General that
adverse health effects (skeletal fluorosis) have not been found in the
U.S. population below 8 mg F/L (0.23 mg/kg/day).
2. Infants and children. EPA has concluded previously that in rats,
the developmental NOEL for cryolite is 3,000 mg/kg/day (1,584 mg/kg/day
F), that in mice, the developmental NOEL is 100 mg/kg/day (52.8 mg/kg/
day F), and that in rabbits, the developmental NOEL is 30 mg/kg/day
(15.8 mg/kg/day F). The NOEL for reproductive toxicity of cryolite
determined in a 2-generation rat reproduction study was determined by
the Agency to be 46 mg/kg/day (24.3 mg/kg/day F).
These data show clearly that no additional margin of safety is
required for exposure of infants and children to cryolite. The
developmental NOEL ranges from more than 166x (rabbit) to more than
16,000x (rat) for the maximum combined exposure of infants and children
to residues of fluoride from all agricultural uses of cryolite plus
drinking water. The reproductive NOEL is about 256x greater than
maximum combined exposure of infants and children to residues of
fluoride.
F. International Tolerances
No Codex, EC or other international tolerances are in effect for
cryolite; thus, potential dietary exposure to fluoride from the
agricultural use of cryolite on crops would not include imported
foodstuffs.
II. Public Record
A record has been established for this notice under docket control
number [PF-712] (including comments and data submitted electronically
as described below). A public version of the record, including printed,
paper versions of electronic comments, which does not include any
information claimed as CBI, is available for inspection from 8:30 a.m.
to 4 p.m., Monday through Friday, excluding legal holidays. The public
record is located in Room 1132 of the Public Response and Resources
Branch, Field Operations Division (7506C), Office of Pesticide
Programs, Environmental Protection Agency, Crystal Mall #2, 1921
Jefferson Davis Highway, Arlington, VA.
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.
The official record for this rulemaking, as well as the public
version, as described above will be kept in paper form. Accordingly,
EPA will transfer all comments received electronically into printed,
paper form as they are received and will place the paper copies in the
official rulemaking record which will also include all comments
submitted directly in writing. The official rulemaking record is the
paper record maintained at the address in ``ADDRESSES'' at the
beginning of this document.
List of Subjects
Environmental protection, Administrative practice and procedure,
Agricultural commodities, Pesticides and pests, Reporting and
recordkeeping requirements.
Dated: February 24, 1997.
Peter Caulkins,
Acting Director, Registration Division, Office of Pesticide Programs.
[FR Doc. 97-6015 Filed 3-11-97; 8:45 am]
BILLING CODE 6560-50-F
