The Relationship between Fluoride Concentration in the Urine of Workers Exposed to HF in the Environment in Isfahan UCF

Introduction: Hydrogen fluoride is one of the materials which is widely used in making glass, cleaning  silicon, manufacturing florescent lamps, ceramics and also in separating uranium isotopes. On the other hand, exposure to this substance could cause health problems including eye, nose, throat and mucus membranes irritation.This study examines the relationship between fluoride (F) in the urine  of the exposed and unexposed workers and the concentration of hydrofluoric acid ( HF ) in work environment. The other was to compare this amount to standard.

Material and methods: This is a historical cohort study.  22 air samples were obtained from worker’s breathing zones using NIOSH 7902 method. Implementing NIOSH 8308, urine sample of 22 exposed and 22 unexposed workers were collected twice-before they went on duty and after they went off duty (total of 88 urine samples). Air samples were interpreted using ion specific electrode method .The relationship between fluoride (F) in the urine and air were then determined with Pearson correlation test.

Results: The mean fluoride concentration in the breathing zone was 0.172±0.252 ppm. The mean fluoride concentration in post shift urine sample of the exposed and unexposed workers was 1.132±0.691 and 0.726±0.394   mg/g creatinine respectively. When compared to the standard levels (3 ppm  for air and 7 mg/g creatinine for urine), a significant difference was revealed  (p<0.001).

Conclusion: The results of this study showed  that mean of fluoride  concentration in air samples of workers’ breathing zone and urine samples were significantly less than the standard level proposed by NIOSH ( p<0.001) . This confirms the fact that the appropriate preventing measures were present in the workplace. The weak correlation obtained between fluoride in the breathing zone and fluoride in the urine samples was explained by individual protective equipments and good ventilation.