Assessment of fluoride daily intake from water and tea infusions in endemic Ouargla, Algeria

In Algerian Sahara, tea consumption is well established in the local communities. 36 tea infusions were obtained from different specialized stores in Ouargla, Algeria. Fluoride was measured using the Alizarin spectrophotometric method. The fluoride Hazard Quotient (HQ), the Estimated Daily iintake (EDI), and effect of brewing time on fluoride release were calculated. Using the value of 0.08 mg/kg/day as acceptable Reference Daily Intake, as recommended by EPA, it is estimated that consumption of respectively 1 and 4 cups of tea per day would give a Median Hazard Quotient HQ of 0.35 and 0.45. Thus, the EPA Hazard Assessment, fails to identify a significant hazard in these consumptions. However, the tea use on a daily basis is likely a significant source of fluoride in Ouargla city. The median level was 2.49 mg/L, and a wide range was found [0.75 to 5.85 mg/L]. The World Health Organization's current drinking water guideline (1.5mg/L) was surpassed by 75% of infusions tested. For heavy tea users who consume more than four cups of tea daily (1 L), the daily fluoride consumption from tea can range between 13.4 and 104.5% of the fluoride guideline daily dose. This study shows that the release of fluoride increases during the brewing process of 10 to 30 minutes and that black tea would contain double as much as the green teas at a 10 min brewing time.