title: Safety Evaluation of Fluoride Content in Tea Infusions Consumed in the Azores-a Volcanic Region with Water Springs naturally Enriched in Fluoride.
abstract: Tea is the second most commonly consumed beverage in the world. It is well recognized that the consumption of tea in high quantities can promote the development of fluorosis. The main objective of this study is to estimate the exposure to fluoride in the Azores through drinking tea prepared with water from different volcanic locations, by i) investigating the fluoride (F) content of various commercial brands of tea (Camellia sinensis) marketed in Azores and ii) comparing tea releasing rates of F according to brewing time, considering the fluoride concentration in the different types of water used for the infusion. Fluoride contents were determined by ion-selective electrode in 30 samples of drinking water from three different locations and in 450 samples of tea (black and green tea) from three different brands. Fluoride concentration in water ranged from 0.29 to 1.56 ppm (Porto Formoso and Sete Cidades village, respectively). Fluoride concentrations increased with brewing time, reaching the highest values in the Azorean black and green tea infusions. For all the studied brands, a negative correlation was found between tea fluoride contents and the pH of the water used to prepare the infusion. Fluoride concentration in infusions was significantly associated with the background fluoride concentration in drinking water. Since the fluoride concentration in groundwater varies accordingly to the geological conditions and tea consumption can contribute to fluoride intake, it is important to define the limits for tea consumption, particularly in fluoride-rich areas. Graphical Abstract Fluoride concentrations in black and green tea for 3 minutes of brewing time and, association between fluoride concentration and pH with brewing time.
authors.affiliation: Faculty of Sciences and Technology, University of the Azores, Rua da Mãe de Deus, Apartado 1422, 9501-801, Ponta Delgada, Azores, Portugal. diana.ps.linhares@uac.pt.|IVAR, Instituto de Investigação em Vulcanologia e Avaliação de Riscos, University of the Azores, 9501-801 Ponta Delgada, Azores, Portugal. diana.ps.linhares@uac.pt.
authors.forename: Diana Paula Silva
authors.initials: DPS
authors.lastname: Linhares
authors.affiliation: Faculty of Sciences and Technology, University of the Azores, Rua da Mãe de Deus, Apartado 1422, 9501-801, Ponta Delgada, Azores, Portugal.|cE3c, Centre for Ecology, Evolution and Environmental Changes and Azorean Biodiversity Group, University of the Azores, 9501-801 Ponta Delgada, Azores, Portugal.
authors.forename: Patrícia Ventura
authors.initials: PV
authors.lastname: Garcia
authors.affiliation: Faculty of Sciences and Technology, University of the Azores, Rua da Mãe de Deus, Apartado 1422, 9501-801, Ponta Delgada, Azores, Portugal.|School of Sciences, University of Minho, Gualtar Campus, 4710-057, Braga, Portugal.
authors.forename: Leslie
authors.initials: L
authors.lastname: Amaral
authors.affiliation: Faculty of Sciences and Technology, University of the Azores, Rua da Mãe de Deus, Apartado 1422, 9501-801, Ponta Delgada, Azores, Portugal.|IVAR, Instituto de Investigação em Vulcanologia e Avaliação de Riscos, University of the Azores, 9501-801 Ponta Delgada, Azores, Portugal.
authors.forename: Teresa
authors.initials: T
authors.lastname: Ferreira
authors.affiliation: Faculty of Sciences and Technology, University of the Azores, Rua da Mãe de Deus, Apartado 1422, 9501-801, Ponta Delgada, Azores, Portugal.|cE3c, Centre for Ecology, Evolution and Environmental Changes and Azorean Biodiversity Group, University of the Azores, 9501-801 Ponta Delgada, Azores, Portugal.
authors.forename: Armindo
authors.initials: A
authors.lastname: Dos Santos Rodrigues
mesh_terms: D001394:Azores; D004784:Environmental Monitoring; D005459:Fluorides / Q000032:analysis*; D045482:Hot Springs / Q000737:chemistry*; D011174:Portugal; D013662:Tea / Q000737:chemistry*; D014131:Trace Elements / Q000032:analysis*; D018707:Volcanic Eruptions
chemical_list: D013662:Tea; D014131:Trace Elements; D005459:Fluorides
keywords: Daily intake; Fluoride; Safety evaluation; Tea infusions