77 Groundwater and Sustainability: Integrating Science, Technology, and Policy

Groundwater is vital for clean water and food security but faces threats from climate change, population growth, and mismanagement. Integrating science, technology, and policy fosters collaboration, innovation, and effective strategies to ensure its sustainable use for future generations.

Monday, 20 October 2025
8:00 AM - 12:00 PM
HBGCC, 210AB

Balancing Benefits and Risks: Fluoride in Groundwater and Its Impact on Oral Health in Rwanda and East Africa

Paper number: 77-15
Program: Technical Sessions
Time: 11:40 AM – 11:55 AM

Authors

  • Camilla Blomstersjo Presenting Author
    Soederasens Tandklinik, Kageroed
  • Erika Svensson Rossner
    International Relations Office, KTH Royal Institute of Technology, Brinellvaegen 8, Stockholm
  • Peace Uwambaye
    Department of Preventive and Community Dentistry, College of Medicine and Health Sciences, School of Dentistry, University of Rwanda, Kigali
  • Julienne Murererehe
    Department of Preventive and Community Dentistry, College of Medicine and Health Sciences, School of Dentistry, University of Rwanda,, Kigali
  • Telesphore Habiyakare
    College of Science and Technology, University of Rwanda, KIgali
  • Emmanuel Ngendahayo
    Lund University, Lund
  • Julian Ijumulana
    College of Engineering and Technology, University of Dar es Salaam, Dar es Salaam
  • Prosun Bhattacharya
    KTH ROYAL INSTITUTE OF TECHNOLOGY, Department of Sustainable Development, Environmental Science and Engineering, Stockholm

Abstract

Fluoride is widely recognized for its protective role against dental caries, especially when applied topically through fluoridated toothpaste or rinses. However, excessive systemic intake—primarily through drinking water—can lead to adverse health effects, particularly dental and skeletal fluorosis. In East Africa, including Rwanda, elevated fluoride concentrations in groundwater are a growing public health concern. These high levels are largely geogenic, resulting from the weathering of volcanic rocks in regions such as the Rift Valley and Rwanda’s highland zones. Populations relying on groundwater sources, such as boreholes and springs, often face chronic, systemic exposure to fluoride concentrations that exceed the World Health Organization's guideline of 1.5 mg/L.

This dual burden—where fluoride acts both as a preventive agent and a contaminant, presents a complex challenge for oral health policy and water management. In rural and peri-urban areas, access to safe drinking water and oral hygiene resources is limited, contributing to the coexistence of both dental caries and fluorosis. As part of a balanced public health strategy, school-based oral health programs, including weekly, supervised fluoride rinse programs offer a safe and effective method to prevent caries in children without increasing systemic fluoride exposure. As part of a balanced public health strategy, we aim to implement school-based oral health programs that include supervised fluoride rinsing – but only in areas where groundwater fluoride levels are low or within the recommended range. By first identifying regions with elevated fluoride concentrations in drinking water, we can avoid introducing rinsing programs in those areas, thereby minimizing the risk of overexposure and fluorosis. However, in high-fluoride regions, school-based oral health education and preventive care remain especially important, as children are still vulnerable to dental caries despite systemic fluoride exposure.

Addressing fluoride-related oral health challenges in Rwanda and neighboring countries requires integrated measures, where water quality mapping is a critical first step, routine water quality monitoring, public health education, accessible defluoridation technologies, and preventive dental care. Promoting the controlled, topical use of fluoride, especially through school programs that can help ensure the benefits of fluoride are realized while minimizing its risks.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-414464

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