Spatial distribution mapping of drinking water fluoride levels in Karnataka, India: fluoride-related health effects

Chitta R Chowdhury; Khijmatgar Shahnawaz; Divya Kumari; Avidyuti Chowdhury; Raman Bedi; Edward Lynch; Stewart Harding; Martin Grootveld

doi:10.1177/1757913915626744

Spatial distribution mapping of drinking water fluoride levels in Karnataka, India: fluoride-related health effects

Perspect Public Health. 2016 Nov;136(6):353-360. doi: 10.1177/1757913915626744. Epub 2016 Feb 3.

Authors

Chitta R Chowdhury¹, Khijmatgar Shahnawaz², Divya Kumari², Avidyuti Chowdhury³, Raman Bedi⁴, Edward Lynch⁵, Stewart Harding⁶, Martin Grootveld⁷

Affiliations

¹ Department of Oral Biology & Genomic Studies, A B Shetty Memorial Institute of Dental Sciences, Nitte University, Mangalore, India Email: crc.ob.cod@gmail.com.
² Department of Oral Biology & Genomic Studies, A B Shetty Memorial Institute of Dental Sciences, Nitte University, Mangalore, India.
³ Global Child Dental Health Taskforce, King's College London, London, UK.
⁴ Centre for International Dental Child Health, King's College London, London, UK.
⁵ Warwick Dentistry, University of Warwick, Coventry, UK.
⁶ City of London Dental School, BPP University, London, UK.
⁷ Leicester School of Pharmacy, De Montfort University, The Gateway, UK mgrootveld@dmu.ac.uk.

PMID: 26842483
DOI: 10.1177/1757913915626744

Abstract

Objectives: (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.

Materials and 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.

Keywords: Karnataka State of India; drinking water sources; environmental temperature; fluoride; fluorosis.

MeSH terms

Dental Caries
Drinking Water*
Fluorides / analysis*
Fluorosis, Dental / prevention & control*
Humans
India
Water Supply*

Substances

Drinking Water
Fluorides