77-14 Balancing Benefits and Risks: Fluoride in Groundwater and Its Impact on Oral Health in Rwanda and East Africa

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

Presenting Author:

Camilla Blomstersjo

Authors:

Blomstersjo, Camilla¹, Svensson Rossner, Erika², Uwambaye, Peace³, Murererehe, Julienne⁴, Habiyakare, Telesphore⁵, Ngendahayo, Emmanuel⁶, Ijumulana, Julian M.⁷, Bhattacharya, Prosun⁸

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 Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-10566

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