Emergency and Continuous Exposure Guidance Levels for Selected Submarine Contaminants Volume 3 (2009) / Chapter Skim
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4 Hydrogen Fluoride
4 Hydrogen Fluoride
Pages 70-109
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From page 70... ...
The committee considered all that information in its evaluation of the U.S. Navy's 1-h, 24-h, and 90-day exposure guidance levels for hydrogen fluoride.
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From page 71... ...
The primary target of airborne gaseous hydrogen fluoride is the respiratory tract; however, injury to distant organs may also occur because of absorption of substantial amounts of fluoride. Acute effects of hydrofluoric acid include damage to skin and lungs, including severe burns, and sys
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The critical effects of inhalation exposure to hydrogen fluoride are respiratory tract irritation and the induction of respiratory disease. Respiratory tract irritation is documented in animal models and has been observed in controlled human exposure studies.
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From page 73... ...
Upper airway symptoms may have occurred in some situations and gone unreported because they were overshadowed by the lower airway effects. There are suggestions that long-term respiratory tract effects may occur after exposure to hydrogen fluoride at high concentrations as indicated by the development of RADS in one subject and the presence of persistent respiratory symptoms in the general population after the release of hydrogen fluoride during an industrial accident.
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From page 74... ...
It seems reasonable to assume that low corresponds to mild irritation and high corresponds to moderate to marked irritation. In the low-concentration group, four of nine subjects reported mild upper airway irritation.
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From page 75... ...
. Mild upper airway irritation was reported in four of nine subjects in low concentration group, six of seven in middle concentration group, four of seven in high-concentration group; moderate to severe upper airway irritation reported in three of seven in high-concentration group; mild lower airway irritation reported in two of seven and moderate to severe irritation in one of seven in high-concentration group; eye irritation (mild)
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From page 76... ...
. Mild irritation reported by six of 10 and marked irritation by one of 10 subjects; nasal lavage performed immediately and 90 min after exposure; lavage neutrophil count and lavage proteins (TNF-α, PGE2, LTB4, peptide LT)
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From page 77... ...
Given that the studies used small numbers of subjects, the database suggests that a significant fraction of subjects experience moderate to marked irritation at concentrations over 3 ppm but only mild irritation at lower concentrations. Lower Airway Irritation Lower airway irritation has been reported in human subjects exposed to hydrogen fluoride but is generally of less magnitude than upper airway irritation.
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From page 78... ...
(1934) , two subjects exposed to hydrogen fluoride at 32 ppm or higher for several minutes reported cutaneous, ocular, and respiratory tract irritation.
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From page 79... ...
, renal damage, endocrine effects, increased risk of bone fracture, and bone and joint pain (skeletal fluorosis)
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From page 80... ...
Fluoride measured in bone 10 years after the maximal exposures was significantly above normal. Given a hydrogen fluoride concentration of 3 ppm, an 8-h workday, a ventilation rate of 15 m3/day, and complete absorption, the worker's minimum systemic fluoride dose was 8 mg/day, averaged over the entire week, or about 0.08 mg/kg-day for his reported weight of 230 lb (105 kg)
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From page 81... ...
. Increased likelihood of impaired glucose tolerance was associated with intakes above 0.07 mg/kg-day, and increased parathyroid hormone concentrations and secondary hyperparathyroidism were found at fluoride intakes of at least 0.15 mg/kg-day.
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From page 82... ...
fluoride intakes of around 0.05 mg/kg-day (estimated from NRC 2006) , but bone fluoride concentrations appear to be a marker, rather than a determinant, of the risk of skeletal fluorosis (NRC 2006)
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From page 83... ...
exposure at more than 100 ppm results in severe respiratory tract lesions consisting of necrosis or inflammation of the nasal passages and to a lesser extent, if at all, those lesions in the lower airways. Concentration-time relationships have been examined in short-term studies, and it has been uniformly concluded that the acute-lethality data on exposures of 30 min or less are best described by the relationship Cn × t = k, where C = concentration, t = time, k = constant, and n = 2 (Rosenholtz et al.
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From page 84... ...
In summary, short-term animal experiments indicate that the respiratory tract is the primary target of hydrogen fluoride in these exposure scenarios. Nasal sensory nerve activation occurs during exposure in nasal-breathing animals.
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From page 85... ...
The study documents increased systemic burdens of fluoride after hydrogen fluoride exposure and the presence of renal injury in animals exposed at 33 ppm or higher. Acute lethality, probably of respiratory tract origin, was observed, but the failure to include examination of nasal lesions precludes determination of a useful NOAEL.
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From page 86... ...
and Kitzmiller 1935 10 weeks alveolar (guinea pigs, rabbits) lung lesions observed; no lung damage in monkeys, but renal injury observed in monkeys and rabbits; nasal tissues not examined 8.6, 33 6 h/day, Rat, mouse, guinea pig, rabbit, dog.
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From page 87... ...
Exposure concentrations were 0, 1, 10, 25, 65, and 100 ppm. Exposure at 65 or 100 ppm caused 100% mortality; 100% mortality also occurred in female rats in the 25-ppm group, but no male rats exposed at this concentration died.
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From page 88... ...
In summary, mortality and respiratory tract injury commonly result from single and repeated 6-h inhalations. Nasal lesions are probably present, but histologic examination of nasal tissues after repeated exposures has not been uniformly performed or, if performed, may have missed the affected area.
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From page 89... ...
Total fluoride exposures of the occupationally exposed men were estimated to be 3-27 mg/day from drinking water and occupational exposure compared with 2-13 mg/day in a group exposed to fluoride only from drinking water. The intakes correspond to fluoride doses of 0.03-0.2 mg/kg-day and 0.05-0.4 mg/kg-day for the low and high exposure groups, respectively, on the basis of 70-kg body weight (NRC 2006)
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From page 90... ...
Thus, with or without skeletal fluorosis, men with high fluoride intakes had reduced serum testosterone. The mean serum fluoride concentration associated with reduced testosterone was 0.24 mg/L in the men with skeletal fluorosis and 0.19 mg/L in the relatives without fluorosis but only 0.05 mg/L in the control group.
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From page 91... ...
. Urinary fluoride concentrations as high as 44 mg/L have been reported after occupational fluoride exposures in excess of 3 mg/m3 (Derryberry et al.
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From page 92... ...
peripheral blood lymphocytes from occupational exposures to F- at 1995; Meng 0.50-0.80 mg/m3 (mostly as HF and SiF4) and Zhang 1997 − Abbreviations: CHO, Chinese hamster ovary; F , fluoride ion; G2, phase G2 of cell cycle; HF, hydrogen fluoride; IC10, inhibitory concentration at 10%; NaF, sodium fluoride; NOAEC, no observable adverse effect concentration; SCE, sister-chromatid exchange; SHE, Syrian hamster embryo; SiF4, tetrafluorosilane.
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From page 93... ...
. TOXICOKINETIC AND MECHANISTIC CONSIDERATIONS Several lines of reasoning suggest that respiratory tract irritation by hydrogen fluoride results from local effects due to its acidic nature.
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From page 94... ...
Blood fluoride concentrations were increased in a concentration-dependent manner after 35-min isolated upper respiratory tract exposure to hydrogen fluoride and indicated that rapid and efficient absorption occurs in the nasal cavity (Morris and Smith 1982)
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From page 95... ...
Absorption efficiencies can approach 99-100%. In that regard, gastrointestinal absorption appears to be similar to respiratory tract absorption.
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TABLE 4-7 Emergency and Continuous Exposure Guidance Levels for Hydrogen Fluoride Current U.S. Navy Values Committee Recommended Exposure Level (ppm)
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From page 97... ...
No significant short-term or long-term health effects would be expected in connection with the lower airway lymphocytic inflammation. Animal studies indicate that the lower respiratory tract may be more sensitive to the effects of hydrogen fluoride than nasal tissues.
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From page 98... ...
for many years, so precise evaluation of the effects of hydrogen fluoride is difficult. Nonetheless, acute exposure to hydrogen fluoride results in mild lower respiratory tract (for example, tracheobronchial)
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From page 99... ...
. The proposed 90-d CEGL of 0.04 ppm most likely protects against systemic fluoride-induced toxicity if airborne hydrogen fluoride is the only important source of fluoride exposure.
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. Persons who have fluoridated water on shore will have total systemic fluoride intakes on board a submarine that will be lower than those on shore.
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From page 101... ...
b Assumes that drinking water on submarine is primarily from reverse-osmosis unit. Purified water is expected to have low fluoride concentrations (<0.15 mg/L; NRC 2006)
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From page 102... ...
1995. Sodium fluoride-induced chromosome aberrations in different cell cycle stages.
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From page 103... ...
1976. Plasma fluoride concentrations in rats acutely poisoned with sodium fluoride.
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From page 104... ...
1997. Sodium fluoride induced chromosome aberrations and sister chromatid exchange in cultured human lymphocytes.
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From page 105... ...
Presentation to the First Meeting on Emergency and Continuous Ex posure Guidance Levels for Selected Submarine Contaminants, June 17, 2008, Washington, DC.
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From page 106... ...
2002. Human exposure to hydrogen fluoride induces acute neutrophilic, eicosanoid, and antioxidant changes in nasal lavage fluid.
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From page 107... ...
1992. Bone mass increase and glucose tolerance in rats chronically treated with sodium fluoride.
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From page 108... ...
1956. Incipient chronic fluoride intoxication from drinking water.
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From page 109... ...
2007. Dose effect relationship between drinking water fluoride levels and damage to liver and kidney functions in children.
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