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Fluoride in workplace air and in urine of workers concentrating fluorspar
Author(s) -
Rees Doh David Bch,,
Rama Dhirajlal B. K.,
Yousefi Vali
Publication year - 1990
Publication title -
american journal of industrial medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.7
H-Index - 104
eISSN - 1097-0274
pISSN - 0271-3586
DOI - 10.1002/ajim.4700170303
Subject(s) - medicine , fluoride , urine , occupational exposure , environmental health , inorganic chemistry , chemistry
The urinary fluoride concentrations of workers exposed to calcium fluoride (CaF 2 ) during fluorspar processing were measured. Personal dust measurement showed that the mean occupational exposure to fluoride for 12 workers in the most dusty environment was 24.3 mg/m 3 , which is 9.7 times the threshold limit value (TLV) of 2.5 mg/m 3 . Exposure was below the TLV for the remaining 23 workers. Urinary fluoride concentrations were measured pre‐ and postshift. The heavily exposed workers had a mean preshift concentration of 3.3 mg/liter (range 1.4–8.5 mg/liter), only slightly higher than the mean of 2.8 mg/liter (range 1.3–4.2 mg/liter) in the workers with fluoride exposure below the TLV. Four of the preshift concentrations exceeded the recommended upper limit of 4 mg/liter. The mean postshift concentration for workers exposed above the TLV was 4.4 mg/liter (range 2.4–7.1 mg/liter) and the difference between pre‐ and postshift concentrations was significant (p < 0.05). Only one urinary concentration exceeded the recommended upper limit of 7 mg/liter. There was poor correlation between intensity of environmental exposure to fluorspar and postshift fluoride concentration in the urine. Eighteen workers provided a urine sample 7‐14 hr after the end of a shift. The mean fluoride concentration was 4.7 mg/liter (range 2.4–11.7 mg/liter), which exceeded their postshift concentration by 0.2 mg/liter. These results indicate that the low aqueous solubility of fluorspar reduced the biologic availability of the fluoride ion but that this did not prevent excessive fluoride absorption in some workers.