Fluoride Exposure from Groundwater as Reflected by Urinary Fluoride and Children's Dental Fluorosis in the Main Ethiopian Rift Valley

"Fluoride Exposure from Groundwater as Reflected by Urinary Fluoride and Children's Dental Fluorosis in the Main Ethiopian Rift Valley." Science of The Total Environment 496, no. 0: 188-97 (10/15/2014 Forthcoming).

Lee Kuan Yew School of Public Policy Research Paper No. 14-21 (IWP)

28 Pages Posted: 11 Aug 2014

See all articles by Tewodros Rango

Tewodros Rango

Duke University - Nicholas School of the Environment

Avner Vengosh

Duke University - Nicholas School of the Environment

Marc Jeuland

Duke University - Sanford School of Public Policy

Redda Tekle-Haimanot

Addis Ababa University

Peter McCornick

International Water Management Institute (IWMI)

Christopher Paul

NCCU Public Administration; Duke University

Erika Weinthal

Duke University - Nicholas School of the Environment

Date Written: July 12, 2014

Abstract

This cross-sectional study explores the relationships between F─ exposure in drinking water consumed by children in the Main Ethiopian Rift (MER) Valley, on the one hand, and urinary F─ concentrations and dental fluorosis (DF), on the other. We examined the DF prevalence and severity among 491 children (10 to 15 years old) who are life-long residents of 33 rural communities in which groundwater concentrations of F─ cover a wide range. A subset of 156 children was selected for urinary F─ measurements. Our results showed that the mean F─ concentrations in groundwater were 8.5±4.1 (range: 1.1-18 mg/L), while those in urine were 12.1±7.3 mg/L (range: 1.1-39.8 mg/L). The prevalence of mild, moderate, and severe DF in children’s teeth was 17%, 29%, and 45%, respectively, and the majority (90%; n=140) of children’ had urinary F─ concentrations above 3 mg/L. The exposure-response relationship between F─ and DF was non-linear, with DF severity tending to level off above a F─ threshold of ~6 mg/L, most likely due to the fact that at ~6 mg/L the enamel is damaged as much as can be clinically observed in most children. We also observed differential prevalence (and severity) of DF, and urinary excretion, across children exposed to similar F─ concentrations in water, which highlights the importance of individual-specific factors (e.g., dietary, genetic, or behavioral) in addition to the F─ content in drinking water. In addition to the study of children in areas of high F─ exposure, we investigated urinary F─ in children from communities where defluoridation remediation was taking place. The lower F─ in urine in this population demonstrates the capacity of the urinary F─ method to monitor individual and community intervention programs for F─ reduction over a relatively short time period (months).

Keywords: drinking water quality; urinary biomarker; exposure-response; defluoridation, risk assessment; East Africa

Suggested Citation

Rango, Tewodros and Vengosh, Avner and Jeuland, Marc and Tekle-Haimanot, Redda and McCornick, Peter and Paul, Christopher and Weinthal, Erika, Fluoride Exposure from Groundwater as Reflected by Urinary Fluoride and Children's Dental Fluorosis in the Main Ethiopian Rift Valley (July 12, 2014). "Fluoride Exposure from Groundwater as Reflected by Urinary Fluoride and Children's Dental Fluorosis in the Main Ethiopian Rift Valley." Science of The Total Environment 496, no. 0: 188-97 (10/15/2014 Forthcoming)., Lee Kuan Yew School of Public Policy Research Paper No. 14-21 (IWP), Available at SSRN: https://ssrn.com/abstract=2478524

Tewodros Rango

Duke University - Nicholas School of the Environment ( email )

Box 90328
Durham, NC 27708-0328
United States

Avner Vengosh

Duke University - Nicholas School of the Environment ( email )

Box 90328
Durham, NC 27708-0328
United States

Marc Jeuland (Contact Author)

Duke University - Sanford School of Public Policy ( email )

201 Science Drive
Box 90312
Durham, NC 27708-0239
United States

Redda Tekle-Haimanot

Addis Ababa University ( email )

King George VI St
Addis Ababa, 1000
Ethiopia

Peter McCornick

International Water Management Institute (IWMI) ( email )

127, Sunil Mawatha,
Pelawatte,
Battaramulla
Sri Lanka

Christopher Paul

NCCU Public Administration ( email )

Durham, NC 27707
United States
919-530-5199 (Phone)

HOME PAGE: http://www.nccu.edu/academics/sc/socialsciences/publicadministration/

Duke University ( email )

100 Fuqua Drive
Durham, NC 27708-0204
United States

Erika Weinthal

Duke University - Nicholas School of the Environment ( email )

Box 90328
Durham, NC 27708-0328
United States

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