Fluoride Action Network


SUMMARY: The city of San Luis Potosi (SLP), Mexico, is located in an area where drinking water contains excessive quantities of natural fluoride. Also in this city is located a small industry that produces hydrofluoric acid. In order to investigate both routes of exposure to fluoride (industrial air and drinking water), we conducted a pilot study in workers of this industry. The study involved 60 male workers, divided into two groups according to their work area: the production and the office groups. Although the exposure to fluoride by the water ingestion pathway was similar for both groups, the occupational-exposure to fluoride was 12 times higher in the production area. Workers in this area had higher levels of fluoride in urine than workers in the office area. This difference was observed in the preshift and the postshift samples. A multivariate regression analysis showed that the workplace explained 33% of the fluoride content of the urinary samples, whereas tap water ingestion explained only 8%. The higher air fluoride levels in the production area could explain the high number of workers who present a pre-clinical phase of skeletal fluorosis. Although our results illustrate the exposure to fluoride of workers in the production area by two pathways, water and workplace air, it would be advisable to explore in more detail the participation of other path-ways of exposure, like diet and soft drinks.