UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

OFFICE OF PREVENTION, PESTICIDES

AND TOXIC SUBSTANCES

MEMORANDUM

SUBJECT:	Sodium Fluoride – Incident Report Summary

PC Code: 	075202

FROM:	Jonathan Chen, Ph.D.

	Senior Toxicologist

	Risk Assessment and Science Support Branch (RASSB)

Antimicrobial Division (7510C)

THROUGH:	Norm Cook

Chief

RASSB / AD

TO:		Sanyvette Williams, Chemical Review Manager

		Regulatory Management Branch II

		Antimicrobials Division (7510P)

Attached is RASSB’s incident reports summary associated with sodium fluoride.

INCIDENT REPORTS ASSOCIATED WITH

Sodium Fluoride

 (PC CODE: 075202)

August 3, 2007

U.S. Environmental Protection Agency

Office of Pesticide Programs

Antimicrobials Division

TABLE OF CONTENTS

  TOC \o "1-3" \h \z \u    HYPERLINK \l "_Toc174769761"  0.0 INTRODUCTION	  PAGEREF _Toc174769761 \h  1

  HYPERLINK \l "_Toc174769762"  1.0 	INCIDENT REPORT DATA ASSOCIATED WITH HEALTH EFFECTS	  PAGEREF _Toc174769762 \h  1

  HYPERLINK \l "_Toc174769763"  1.1	OPP’s Incident Data System (IDS)	  PAGEREF _Toc174769763 \h  2

  HYPERLINK \l "_Toc174769764"  1.2	Poison Control Center (1993 – 2003)	  PAGEREF _Toc174769764 \h  2

  HYPERLINK \l "_Toc174769765"  1.4	National Pesticide Telecommunications Network (NPTN)	  PAGEREF _Toc174769765 \h  3

  HYPERLINK \l "_Toc174769766"  1.5	Incident Reports / Epidemiological Studies Published in Scientific Literature	  PAGEREF _Toc174769766 \h  3

  HYPERLINK \l "_Toc174769767"  1.5.1 Acute Effects	  PAGEREF _Toc174769767 \h  3

  HYPERLINK \l "_Toc174769768"  1.5.2 Chronic Effects	  PAGEREF _Toc174769768 \h  4

  HYPERLINK \l "_Toc174769769"  2.0	CONCLUSIONS	  PAGEREF _Toc174769769 \h  5

  HYPERLINK \l "_Toc174769770"  3.0	REFERENCES	  PAGEREF _Toc174769770 \h  6

0.0	INTRODUCTION tc \l1 "0.0	INTRODUCTION

The purpose of this chapter is to review the evidence of health effects in humans resulting from exposure to sodium Fluoride.

Two approaches are used in this section:

The potential health effects of sodium fluoride in humans, reported as incident reports from different sources, are summarized.

A literature search of chronic health effects associated with sodium fluoride exposure, including results of epidemiological studies, is summarized.

1.0 	INCIDENT REPORT DATA ASSOCIATED WITH HEALTH EFFECTS

The following databases have been consulted for incident data:

OPP Incident Data System (IDS) - The Incident Data System of The Office of Pesticide Programs (OPP) of the Environmental Protection Agency (EPA) contains reports of incidents from various sources, including registrants, other federal and state health and environmental agencies and individual consumers, submitted to OPP since 1992.  Reports submitted to the Incident Data System represent anecdotal reports or allegations only, unless otherwise stated.  Typically no conclusions can be drawn implicating the pesticide as a cause of any of the reported health effects.  Nevertheless, sometimes with enough cases and/or enough documentation risk mitigation measures may be suggested.

Poison Control Centers - as the result of a data purchase by EPA, OPP received Poison Control Center data covering the years 1993 through 2003 for all pesticides.  Most of the national Poison Control Centers (PCCs) participate in a national data collection system, the Toxic Exposure Surveillance System, which obtains data from about 65-70 centers at hospitals and universities.  PCCs provide telephone consultation for individuals and health care providers on suspected poisonings involving drugs, household products, pesticides, etc.

California Department of Pesticide Regulation - California has collected uniform data on suspected pesticide poisonings since 1982.  Physicians are required, by statute, to report to their local health officer all occurrences of illness suspected of being related to exposure to pesticides.  The majority of the incidents involve workers.  Information on exposure (worker activity), type of illness (systemic, eye, skin, eye/skin and respiratory), likelihood of a causal relationship, and number of days off work and in the hospital are provided.

National Pesticide Telecommunications Network (NPTN) - NPTN is a toll-free information service supported by OPP.  A ranking of the top 200 active ingredients for which telephone calls were received during calendar years 1984-1991, inclusive, has been prepared.  The total number of calls was tabulated for the categories of human incidents, animal incidents, calls for information, and others.

1.1	OPP’s Incident Data System (IDS) tc \l2 "1.1 	OPPs Incident Data System (IDS)

There is no incident has been reported in the OPP incident data system is specific associated with sodium fluoride exposure.

1.2	Poison Control Center (1993 – 2003) tc \l2 "1.2 	 Poison Control Center

There are 5 incidents been reported in the American Association of Poison Control Centers Toxic Exposure Surveillance System (TESS) between 1993-2003.

Between 1993-1998, two cases involved oral exposure are reported.  The patients exhibited symptoms as a result of the exposure which are consider have moderate effects and were not life-threatening and the patients have returned to a pre-exposure state of well-being with no residual disability or disfigurement.  The reported symptoms including blurred visions, and chest and abdominal pain.

Between 1999-2003, three cases (two involved oral exposure and one involved aerosol inhalation exposure) are reported.  All the three cases are classified as minor effects as the result of the exposure and the symptoms resolve rapidly and returned to a pre-exposure state of well being and have no residual disability or disfigurement.  For oral exposure, vomiting is the primary reported symptom.  For inhalation exposure, nausea and headache are the primary reported symptoms.

1.3	California Data - 1982 through 2003

There is one sodium fluoride involved incident reported.  A worker applies a wood preservative to the base of a telephone pole and got some on his cheek.  While wiping it off with his sleeve, he rubbed it into his left eye.  He flushed the eye with a portable kit. The reported symptoms include pain, burning sensation, and marked conjunctival infection in the left eye. However, creosote and potassium dichromate may also be involved in this incident.

1.4	National Pesticide Telecommunications Network (NPTN) tc \l2 "1.4  National Pesticide Telecommunications Network (NPTN)

There is no incident reported in the NPTN database related to sodium fluoride exposure.

1.5	Incident Reports / Epidemiological Studies Published in Scientific Literature

There are some concerns associated with sodium fluoride exposure reported in the public literature.

1.5.1 Acute Effects

Direct contact with fluoride can result in tissue damage. At high concentrations, fluoride can cause irritation and damage to the respiratory tract, stomach, and skin following inhalation, oral, and dermal exposure, respectively (ATSDR, 2003).  Dermal irritation and contact urticaria have been reported from dermal contact of sodium fluoride (Camarasa et al., 1993).

There are incidences associated with sodium fluoride through acute oral ingestion (Abukurah et al. 1972; Hayes, 1975; Eichler et al., 1982).  As summarized by Dreisbach (1987), through oral exposure, soluble fluoride salts may cause salivation, nausea and vomiting, diarrhea, and abdominal pain. Later, weakness, tremors, shallow respiration, carpopedal spasm, and convulsions occur. Death is by respiratory paralysis. If death does not occur immediately, jaundice and oliguria may appear. Experience with oral fluoride supplements used to prevent tooth decay has been reassuring; no adverse effects occur unless enormous amounts are ingested.  A variety of metabolic disorders may occur, including hypocalcemia, hypomagnesemia, metabolic and/or respiratory acidosis and sometimes hyperkalemia, may also occur in acute fluoride poisoning (Gosselin, et al., 1984).

 (Abukurah et al. 1972). Within 14 hours following exposure, the patient experienced 63 episodes of ventricular fibrillation. For example, a plasma fluoride level of 2,000 μg/L was reported in a case of severe oral poisoning with 53 g fluoride as sodium fluoride (Abukurah et al. 1972).  The noticed cardiac symptoms may be associated with the metabolic disorder resulted from acute fluoride exposure.

1.5.2 Chronic Effects

Fluoride intake has been shown to decrease the prevalence of dental caries.  However, the primary concerns associated with chronic exposure to high level of fluoride, especially through oral route, can cause dental fluorosis and can result in an increased prevalence of bone fractures in the elderly or skeletal fluorosis (ATSDR, 2003).

Numerous epidemiological studies have examined the issue of a connection between fluoridated water with heart disease. There are studies show there were no significant differences between areas with different fluoride levels in mortality due to coronary disease, angina, and other heart disease (Leone et al. 1954; Heasman and Martin 1962).  Although there is a study show a positive relationship between heart disease and water fluoridation (Hagan et al. 1954), this study was criticized for the sampling population was not properly age adjusted (Jansen and Thomson, 1974).  There are other studies have suggested fluoridation can decrease the incidence of cardiovascular disease (Bernstein et al. 1966; Luoma 1980; and Taves, 1978).

Numerous epidemiological studies have examined the issue of a connection between fluoridated water and cancer. Most studies have not found significant increases in cancer mortality (Erickson 1978; Hoover et al. 1976; Rogot et al. 1978; Taves 1977) or site-specific cancer incidence (Freni and Gaylor 1992; Gelberg et al. 1995; Hoover et al. 1976; Mahoney et al. 1991; McGuire et al. 1991). However, a couple of studies have reported significant fluoridation-related increases in cancer mortality.  In order to address the cancer concern,  the National Toxicology Program (NTP) conducted two chronic oral bioassays of fluoride administered as sodium fluoride (0, 25, 100, or175 ppm) in drinking water for 103 weeks, using F344/N rats and B6C3F1 mice (NTP, 1990). The estimated total fluoride intake (including fluoride in both water and diet) of control, low-, medium-, and high-dose male rats as 0.2, 0.8, 2.5, and 4.1 mg/kg/day, respectively. Similarly, the high doses for female rats, male mice, and female mice were 4.5, 8.1, and 9.1 mg/kg/day, respectively. The study found osteosarcomas in the bone of 1/50 male rats in the mid-dose group and 3/80 of the high dose male rats. An additional high-dose male had an extra skeletal osteosarcoma in subcutaneous tissue. Osteosarcomas were observed in one low-dose male mouse, one low-dose female mouse, and one control female mouse. There was also one osteoma in a control female mouse. No osteosarcomas were observed at mid- or high-dose levels in female rats or male or female mice.

In 1996, the EPA’s Office of Prevention, Pesticides, and Toxic Substances classified sodium aluminofluoride (cryolite) as a “Group D” carcinogen (not classifiable as to carcinogenicity), citing the National Toxicology Program’s carcinogenicity study of sodium fluoride (NTP, 1990). More recently, the National Acedemy of Sciences (NAS, 2006) at the request of the EPA, conducted a review of the toxicologic, epidemiologic, and clinical data on fluoride since the 1993 NAS report. With respect to carcinogenicity, the 2006 NAS report concluded that “ on the basis of the committee’s collective consideration of data from humans, genotoxicity assays, and studies of mechanism of action in cell systems…the evidence on the potential of fluoride to initiate or promote cancers, particularly of the bone, is tentative and mixed.” This recent conclusion is consistent with the past conclusion of OPPTS regarding carcinogenic potential of fluoride.

2.0	CONCLUSIONS

There are only limited acute incidences associated with sodium fluoride used in wood preservatives.  All the symptoms are classified as either minor or moderate.  Historically, there are some fatal incidences associated with oral exposure to sodium fluoride, it happened at much higher concentration.

For chronic exposure, fluoride intake has been shown to decrease the prevalence of dental caries. At high level of fluoride, especially through oral route, can cause dental fluorosis and can result in an increased prevalence of bone fractures in the elderly or skeletal fluorosis (ATSDR, 2003).  In 1996, the EPA’s Office of Prevention, Pesticides, and Toxic Substances classified sodium aluminofluoride (cryolite) as a “Group D” carcinogen (not classifiable as to carcinogenicity).

REFERENCES

Abukurah AR, Moser AM Jr, Baird CL, et al. 1972. Acute sodium fluoride poisoning. JAMA 222:816- 817.

Agency for Toxic Substances and Disease Registry (ATSDR) , 2003. Toxicological Profile for Fluoride, Hydrogen Fluoride, and Fluorine.  U.S. Dept. of Health and Human Services.  Public Health Service

Bernstein DS, Sadowsky N, Hegsted DM, et al. 1966. Prevalence of osteoporosis in high- and lowfluoride areas in North Dakota. JAMA 198(5):85-90.

Camarasa JG, Serra-Baldrich E, Lluch M, et al. 1993. Contact urticaria from sodium fluoride. Contact Dermatitis 28(5):294.

Dreisbach, R.H. 1987.  Handbook of Poisoning. 12th ed. Norwalk, CT: Appleton and Lange, , p. 217 Cited in Hazardous Substances Data Bank (HSDB) 2007-06-04 Update

Erickson JD. 1978. Mortality in selected cities with fluoridated and non-fluoridated water supplies. N. Eng J Med 298:1112-1116.

Freni SC, Gaylor DW. 1992. International trends in the incidence of bone cancer are not related to drinking water fluoridation. Cancer 70(3):611-618.

Gelberg KH, Fitzgerald EF, Hwang S-A, et al. 1995. Fluoride exposure and childhood osteosarcoma: A case-control study. Am J Pub Health 85(12):1678-1680.

Gosselin RE, Smith RP, Hodge HC. 1984. Clinical toxicology of commercial products. 5th ed. Baltimore, MD: Williams & Wilkens, 112, 185-193.

Hagan TL, Pasternack M, Scholz GC. 1954. Waterborne fluorides and mortality. Public Health Rep. 69:450-454.

Hayes WJ Jr. 1975. Ingestion of sodium fluoride as roach powder caused 47 deaths in 260 cases in U.S.A. In: Toxicology of pesticides. Baltimore, MD: Williams & Wilkins, 323.

Heasman MA, Martin AE. 1962. Mortality in areas containing natural fluoride in their water supplies. Mon Bull Minist Health Public Health Lab Serv 21:150-173. Hoover et al. 1976

Hoover RN, McKay FW, Fraumeni JF Jr. 1976. Fluoridated drinking water and the occurrence of cancer. J Natl Cancer Inst 57(4):757-768.

Jansen I, Thomson HM. 1974. Heart deaths and fluoridation. Fluoride 7:52-57.

Leone NC, Leatherwood EC, Petrie IM, et al. 1964. Effect of fluoride on thyroid gland: Clinical study. J Am Dental Assoc 69:179-180.

Luoma H. 1980. Fluoride and magnesium, two ions in the prevention of calcium salt imbalance, including caries prevention, in man and animals. Proc Finn Dent Soc 76:73-81.

Mahoney MC, Nasca PC, Burnett WS, et al. 1991. Bone cancer incidence rates in New York State: Time trends and fluoridated drinking water. Am J Public Health 81(4):475-479.

McGuire SM, Vanable ED, McGuire JA, et al. 1991. Is there a link between fluoridated water and osteosarcoma? J Am Dent Assoc 122:38-45. NAS, 2006

National Academy of Science (NAS).  2006. Fluoride in Drinking Water: A Scientific Review of EPA's Standards. The National Academies Press. United States.

NTP. 1990. NTP technical report on the toxicology and carcinogenesis studies of sodium fluoride in F344丯删瑡⁳湡㙂㍃ㅆ洠捩搨楲歮湩慷整⁲瑳摵 敩⥳慗桳湩瑧湯䍄›敄慰瑲敭瑮漠效污桴摅捵 瑡潩Ɱ愠摮圠汥慦敲慎楴湯污吠硯捩汯杯⁹牐杯慲⹭ 丠偔吠⁒㤳ⰳ丠䡉瀠扵楬慣楴湯渠⹯㤠ⴰ㠲㠴മ

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Rogot E, Sherrett AR, Feinleib M, et al. 1978. Trends in urban mortality in relation to fluoridation status. Am J Epidemiol 107:104-112.

Taves DR. 1977. Fluoridation and cancer mortality. In: Origins of human cancer: Book A: Incidence of cancer in humans. Cold Spring Harbor Conferences on Cell Proliferation 4:357-366.

Taves DR. 1978. Fluoridation and mortality due to heart disease. Nature 272:361-362.

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