Fluorine (soluble fluoride) (CASRN 7782-41-4)
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0053
Fluorine (soluble fluoride); CASRN 7782-41-4
Health assessment information on a chemical substance is included in IRIS
only after a comprehensive review of chronic toxicity data by U.S. EPA
health scientists from several Program Offices and the Office of Research
and Development. The summaries presented in Sections I and II represent
a consensus reached in the review process. Background information and
explanations of the methods used to derive the values given in IRIS are
provided in the Background Documents.
STATUS OF DATA FOR Fluorine (soluble fluoride)
File First On-Line 01/31/1987
Category (section) |
Status |
Last Revised |
---|---|---|
Oral RfD Assessment (I.A.) | on-line | 06/01/1989 |
Inhalation RfC Assessment (I.B.) | no data | |
Carcinogenicity Assessment (II.) | no data |
_I. Chronic Health Hazard Assessments for Noncarcinogenic Effects
_I.A. Reference Dose for Chronic Oral Exposure (RfD)
Substance Name — Fluorine (soluble fluoride)
CASRN — 7782-41-4
Primary Synonym — Fluoride
Last Revised — 06/01/1989
The oral Reference Dose (RfD) is based on the assumption that thresholds
exist for certain toxic effects such as cellular necrosis. It is expressed
in units of mg/kg-day. In general, the RfD is an estimate (with uncertainty
spanning perhaps an order of magnitude) of a daily exposure to the human
population (including sensitive subgroups) that is likely to be without
an appreciable risk of deleterious effects during a lifetime. Please refer
to the Background Document for an elaboration of these concepts. RfDs
can also be derived for the noncarcinogenic health effects of substances
that are also carcinogens. Therefore, it is essential to refer to other
sources of information concerning the carcinogenicity of this substance.
If the U.S. EPA has evaluated this substance for potential human carcinogenicity,
a summary of that evaluation will be contained in Section II of this file.
__I.A.1. Oral RfD Summary
Critical Effect |
Experimental Doses* |
UF |
MF |
RfD |
---|---|---|---|---|
Objectionable dental Epidemiologic Study Hodge, 1950, cited |
NOAEL: 1 ppm (converted 0.06 mg/kg/day LOAEL: 2 ppm |
1 |
1 |
6E-2 mg/kg/day |
*Conversion Factors: see text
__I.A.2. Principal and Supporting Studies (Oral RfD)
Hodge, H.C. 1950. The concentration of fluorides in drinking water to give
the point of minimum caries with maximum safety. J. Am. Dent. Assoc. 40:
436. Cited in: Underwood, E.J. 1977. Trace Elements in Human and Animal
Nutrition. Academic Press, NY.
Fluoride-related compounds are used in the prevention of dental caries.
Extensive human epidemiologic studies with large populations have been carried
out over the last 40 years. The NOAEL (1 ppm) and LOAEL (2 ppm) in drinking
water are defined within a narrow dose range.
Hodge (1950) studied children consuming fluoride in their drinking water.
Fluoride levels of 0-14 ppm were investigated. Dental mottling was the
parameter of interest. Fluoride levels of 2-10 ppm produced a linear dose-
response curve (increasing mottling with increasing dose). Fluoride levels of
0.1-1.0 ppm produced no observable effect. An assumption of 20 kg bw and 1
L/day water consumption for children was used, since the children studied were
12-14 years old. It is further assumed that a 20-kg child consumes 0.01 mg of
fluoride/kg bw/day in the diet (50 FR 20164). Thus, a total intake would be
approximately 0.06 mg/kg/day.
__I.A.3. Uncertainty and Modifying Factors (Oral RfD)
UF — Uncertainty factors were not deemed necessary since the NOAEL is that of
the critical effect (i.e., dental fluorosis) in a sensitive population of
humans (i.e., children) for a length of exposure that encompasses both the
critical effect and the sensitive population.
MF — None
__I.A.4. Additional Studies/Comments (Oral RfD)
Dental fluorosis results from excess exposure to fluoride during the age of
calcification of the teeth (up to about 8 years of age for anterior teeth).
Dental fluorosis in its mild form is characterized by white opaque areas
covering 50% of a given tooth; in its severe form, dental fluorosis is
characterized by brown to black stains and pitting (50 FR 20164). There is
considerable controversy over whether objectionable dental fluorosis (moderate
and severe) is a toxic and/or adverse health effect. However, the U.S. EPA
has determined that objectionable dental fluorosis is a cosmetic effect and
not a toxic and/or adverse health effect (50 FR 47142). Numerous
epidemiologic studies have been conducted in the U.S. concerning the
relationship between dental fluorosis and fluoride levels in drinking water
(50 FR 20164). Based on these studies, the NOAEL for objectionable dental
fluorosis is approximately 1.0 ppm fluoride in drinking water. Assuming that
a child weighs 20 kg, drinks 1.0 L of water/day and ingests fluoride at 0.01
mg/kg/day in the diet (50 FR 20164), a NOAEL of 1 ppm fluoride in drinking
water corresponds to 0.06 mg/kg/day. Since data are available for the only
susceptible population (children), an uncertainty factor of 1 is appropriate.
It has been estimated that the development of crippling skeletal fluorosis in
man requires the consumption of 20 mg or more of fluoride/person/day over a
20-year period, i.e., 0.28 mg/kg/day (U.S. EPA, 1985). While the NOEL for
crippling skeletal fluorosis in humans is unknown, a safe level of fluoride
exposure can be determined. No cases of crippling skeletal fluorosis have
been observed in the United States associated with the consumption of 2 L of
water/day containing 4 ppm fluoride (50 FR 20614). Assuming a 70 kg adult
ingests 0.01 mg fluoride/day in the diet and consumes 8 mg fluoride/ day in
drinking water (2 L/day containing 4 ppm fluoride), this would correspond to a
total intake of 0.12 mg/kg/day. Thus, 0.12 mg fluoride/kg/day is a safe
exposure level for this more severe endpoint in adults.
__I.A.5. Confidence in the Oral RfD
Study — High
Database — High
RfD — High
Confidence in both the study and the database is high because the large number of studies conducted in children all support the chosen NOAEL. Confidence in the RfD is high because little uncertainty remains in the toxicity database.
__I.A.6. EPA Documentation and Review of the Oral RfD
Source Document — U.S. EPA. 1985. Federal Register, Vol. 50, p. 20164,
47142.
ECAO-Cincinnati Internal Review, July 1985.
Other EPA Documentation — None
Agency Work Group Review — 08/05/1985, 02/05/1986, 02/26/1986
Verification Date — 02/26/1985
Screening-Level Literature Review Findings — A screening-level review conducted by an EPA contractor of the more recent toxicology literature pertinent to the RfD for Fluorine (soluble fluoride) conducted in November 2001 identified one or more significant new studies. IRIS users may request the references for those studies from the IRIS Hotline at hotline.iris@epa.gov or (202)566-1676.
__I.A.7. EPA Contacts (Oral RfD)
Please contact the IRIS Hotline for all questions concerning this assessment or IRIS, in general, at (202)566-1676 (phone), (202)566-1749 (FAX) or hotline.iris@epa.gov (internet address).
_I.B. Reference Concentration for Chronic Inhalation Exposure (RfC)
Substance Name — Fluorine (soluble fluoride)
CASRN — 7782-41-4
Primary Synonym — Fluoride
Not available at this time.
_II. Carcinogenicity Assessment for Lifetime Exposure
Substance Name — Fluorine (soluble fluoride)
CASRN — 7782-41-4
Primary Synonym — Fluoride
This substance/agent has not undergone a complete evaluation and determination under US EPA's IRIS program for evidence of human carcinogenic potential.
_III.
[reserved]
_IV. [reserved]
_V. [reserved]
_VI. Bibliography
Substance Name — Fluorine (soluble fluoride)
CASRN — 7782-41-4
Primary Synonym — Fluoride
Last Revised — 08/01/1989
_VI.A. Oral RfD References
Hodge, H.C. 1950. The concentration of fluorides in drinking water to give
the point of minimum caries with maximum safety. J. Am. Dent. Assoc.
40: 436.
Underwood, E.J. 1977. Trace elements in human and animal nutrition.
Academic Press, New York. p. 347-369.
U.S. EPA. 1985. Federal Register. Vol. 50, p. 20164, 47142.
_VI.B. Inhalation RfC References
None
_VI.C. Carcinogenicity Assessment References
None
_VII. Revision History
Substance Name — Fluorine (soluble fluoride)
CASRN — 7782-41-4
Primary Synonym — Fluoride
Date |
Section |
Description |
---|---|---|
03/31/1987 | I.A.6. | Documentation corrected |
06/30/1988 | I.A.7. | Contacts switched |
04/01/1989 | V. | Supplementary data on-line |
06/01/1989 | I.A.6. | Work group review dates corrected |
08/01/1989 | VI. | Bibliography on-line |
01/01/1992 | I.A.7. | Secondary contact changed |
01/01/1992 | IV. | Regulatory actions updated |
08/01/1995 | I.A.6. | EPA's RfD/RfC and CRAVE workgroups were discontinued in May, 1995. Chemical substance reviews that were not completed by September 1995 were taken out of IRIS review. The IRIS Pilot Program replaced the workgroup functions beginning in September, 1995. |
04/01/1997 | III., IV., V. | Drinking Water Health Advisories, EPA Regulatory Actions, and Supplementary Data were removed from IRIS on or before April 1997. IRIS users were directed to the appropriate EPA Program Offices for this information. |
12/03/2002 | I.A.6. | Screening-Level Literature Review Findings message has been added. |
_VIII. Synonyms
Substance Name — Fluorine (soluble fluoride)
CASRN — 7782-41-4
Primary Synonym — Fluoride
Last Revised — 01/31/1987
- 7782-41-4
- Fluoride
- Fluoride ion
- Fluoride ion(1-)
- Fluorine
- Fluorine, ion
- Hydrofluoric acid, ion(1-)
- Perfluoride.