title: Spatial distribution mapping of drinking water fluoride levels in Karnataka, India: fluoride-related health effects.
abstract: OBJECTIVE
  (1) To estimate the concentrations of fluoride in drinking water throughout different zones and districts of the state of Karnataka. (2) To investigate the variation of fluoride concentration in drinking water from different sources, and its relationships to daily temperature and rainfall status in the regional districts. (3) To develop an updated fluoride concentration intensity map of the state of Karnataka, and to evaluate these data in the context of fluoride-related health effects such as fluorosis and their prevalence.
  
  
  METHODS
  Aqueous standard solutions of 10, 100 and 1,000 ppm fluoride (F-) were prepared with analytical grade Na+/F-and a buffer; TISAB II was incorporated in both calibration standard and analysis solutions in order to remove the potentially interfering effects of trace metal ions. This analysis was performed using an ion-selective electrode (ISE), and mean determination readings for n = 5 samples collected at each Karnataka water source were recorded.
  
  
  RESULTS
  The F-concentration in drinking water in Karnataka state was found to vary substantially, with the highest mean values recorded being in the north-eastern zone (1.61 ppm), and the lowest in the south-western one (only 0.41 ppm). Analysis of variance (ANOVA) demonstrated that there were very highly significant 'between-zone' and 'between-districts-within-zones' sources of variation (p < 10-5-10-9), results consistent with a substantial spatial variance of water source F-levels within this state.
  
  
  CONCLUSIONS
  The southern part of Karnataka has low levels of F-in its drinking water, and may require fluoridation treatment in order to mitigate for dental caries and further ailments related to fluoride deficiency. However, districts within the north-eastern region have contrastingly high levels of fluoride, an observation which has been linked to dental and skeletal fluorosis. This highlights a major requirement for interventional actions in order to ensure maintenance of the recommended range of fluoride concentrations (0.8-1.5 ppm) in Karnataka's drinking water sources.
authors: Department of Oral Biology & Genomic Studies, A B Shetty Memorial Institute of Dental Sciences, Nitte University, Mangalore, India Email: crc.ob.cod@gmail.com.
authors: Chitta R
authors: CR
authors: Chowdhury
authors: Department of Oral Biology & Genomic Studies, A B Shetty Memorial Institute of Dental Sciences, Nitte University, Mangalore, India.
authors: Khijmatgar
authors: K
authors: Shahnawaz
authors: Department of Oral Biology & Genomic Studies, A B Shetty Memorial Institute of Dental Sciences, Nitte University, Mangalore, India.
authors: Divya
authors: D
authors: Kumari
authors: Global Child Dental Health Taskforce, King's College London, London, UK.
authors: Avidyuti
authors: A
authors: Chowdhury
authors: Centre for International Dental Child Health, King's College London, London, UK.
authors: Raman
authors: R
authors: Bedi
authors: Warwick Dentistry, University of Warwick, Coventry, UK.
authors: Edward
authors: E
authors: Lynch
authors: City of London Dental School, BPP University, London, UK.
authors: Stewart
authors: S
authors: Harding
authors: Leicester School of Pharmacy, De Montfort University, The Gateway, UK mgrootveld@dmu.ac.uk.
authors: Martin
authors: M
authors: Grootveld
mesh_terms: D003731:Dental Caries; D060766:Drinking Water; D005459:Fluorides / Q000032:analysis*; D009050:Fluorosis, Dental / Q000517:prevention & control*; D006801:Humans; D007194:India; D014881:Water Supply
chemical_list: D060766:Drinking Water; D005459:Fluorides
keywords: Karnataka State of India; drinking water sources; environmental temperature; fluoride; fluorosis