Fluoride accumulation in coffee seeds and associated health risks: a case study from Meru District, Tanzania.

Abstract

This study assessed fluoride accumulation in coffee seeds and its potential public health implications in Meru District, Tanzania—a region characterized by naturally high soil fluoride due to volcanic activity. Coffee seeds and water samples were systematically collected from three distinct areas (Meru Lowland, Tengeru, and Meru Highland) and brewed using both local and distilled water. Fluoride concentrations in the brewed coffee were determined using the SPADNS method, and health risks were evaluated through calculations of Estimated Daily Fluoride Intake (EDFI) and Hazard Quotient (HQ). Results revealed that fluoride levels in coffee infusions increased with both altitude and the fluoride content of the brewing water, with the highest concentrations observed in samples brewed with Meru Highland water. A population exposure assessment indicated that a notable proportion of the local community might exceed the recommended fluoride intake, thereby elevating the risk of dental and skeletal fluorosis. These findings underscore the need for targeted public health interventions, such as the promotion of low-fluoride water for coffee preparation. The study provides a comprehensive framework for understanding the soil–water-plant nexus and highlights the importance of mitigating fluoride exposure in regions with high environmental fluoride.

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