title: Sensitivity of two biomarkers for biomonitoring exposure to fluoride in children and women: A study in a volcanic area.
abstract: The natural enrichment of water with fluoride is related to natural sources such as volcanic activity, with it being documented that fluorosis, an endemic and widespread disease in volcanic areas, is associated to the ingestion of high levels of fluoride through water. Thus, in this study, we aimed to define the fluoride concentration in drinking waters of volcanic origin and compare the sensitivity of urine and nail clippings as biomarkers for fluoride exposure in adults and children. Samples of drinking water from four villages in São Miguel Island (Azores) were used and the fluoride concentration was determined, as well the fluoride content in urine and toenails clippings from 66 children and 63 adults from these villages. A validated diet questionnaire, assessing sources of fluoride, was recorded for each participant. The fluoride determination in urine and nail clipping samples was made using a fluoride-specific electrode. A positive correlation was found between the fluoride daily intake and fluoride content in children urine (rs = 0.475; p < 0.001) and in their nail clippings (rs = 0.475; p < 0.001), while in adult women, the fluoride daily intake correlated positively with fluoride content nail clippings (rs = 0.495, p < 0.001). This reveals that nail clippings are more reliable as biomarkers of chronic exposure to fluoride than urine for populations of different ages (children vs. adults). Furthermore, nail clippings are more suitable than urine fluoride levels to assess long term exposure to fluoride in areas where the exposure to fluoride in drinking water is considered within, or slightly above, the recommended legal values.
authors.affiliation: Department of Biology, University of the Azores, 9501-801, Ponta Delgada, Azores, Portugal; CVARG, Center for Volcanology and Geological Risks Assessment, University of the Azores, 9501-801 Ponta Delgada, Azores, Portugal. Electronic address: diana.ps.linhares@uac.pt.
authors.forename: Diana Paula Silva
authors.initials: DPS
authors.lastname: Linhares
authors.affiliation: Department of Biology, University of the Azores, 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. Electronic address: patricia.v.garcia@uac.pt.
authors.forename: Patrícia Ventura
authors.initials: PV
authors.lastname: Garcia
authors.affiliation: Department of Biology, University of the Azores, 9501-801, Ponta Delgada, Azores, Portugal; School of Sciences, University of Minho, Gualtar Campus, 4710-057, Braga, Portugal. Electronic address: leslieamaral40@gmail.com.
authors.forename: Leslie
authors.initials: L
authors.lastname: Amaral
authors.affiliation: Department of Geosciences, University of the Azores, 9501-801 Ponta Delgada, Azores, Portugal; CVARG, Center for Volcanology and Geological Risks Assessment, University of the Azores, 9501-801 Ponta Delgada, Azores, Portugal. Electronic address: teresa.jl.ferreira@azores.gov.pt.
authors.forename: Teresa
authors.initials: T
authors.lastname: Ferreira
authors.affiliation: Piracicaba Dental School, University of Campinas, Piracicaba, SP, Brazil. Electronic address: jcury@unicamp.br.
authors.forename: Jaime A
authors.initials: JA
authors.lastname: Cury
authors.affiliation: Piracicaba Dental School, University of Campinas, Piracicaba, SP, Brazil. Electronic address: wvfilho@unicamp.br.
authors.forename: Waldomiro
authors.initials: W
authors.lastname: Vieira
authors.affiliation: Department of Biology, University of the Azores, 9501-801, Ponta Delgada, Azores, Portugal; CVARG, Center for Volcanology and Geological Risks Assessment, University of the Azores, 9501-801 Ponta Delgada, Azores, Portugal. Electronic address: armindo.s.rodrigues@uac.pt.
authors.forename: Armindo Dos Santos
authors.initials: ADS
authors.lastname: Rodrigues
mesh_terms: D000328:Adult; D001394:Azores; D015415:Biomarkers / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods*; D005260:Female; D005459:Fluorides / Q000032:analysis*; D009050:Fluorosis, Dental; D006801:Humans; D008297:Male; D008875:Middle Aged; D009262:Nails / Q000737:chemistry*; D011795:Surveys and Questionnaires; D014556:Urine / Q000737:chemistry*; D014867:Water / Q000737:chemistry; D014881:Water Supply
chemical_list: D015415:Biomarkers; D014867:Water; D005459:Fluorides
keywords: Biomarkers; Drinking water; Exposure; Fluoride; Volcanism