MWEMA Felix Mwema – The Nelson Mandela African Institution of Science and Technology

Fluoride pollution in soil is often overlooked in comparison to heavy metals and organic pollutants, but it has negative impact to human health and plants when it exceeds the limits. Fluoride consumption beyond 1.5 mg/L in water can induce a variety of bone disorders, including tooth mottling and lesions of the endocrine glands, thyroid, liver and other organs to humans while on plants it causes necrosis and chlorosis. It is often overlooked because of its ability to affect humans and animal slowly compared to other pollutants like heavy metals. Once fluoride is accumulated in soils, it can appears in different forms and the soluble fluoride is up-taken by plants and finds its way into the food chain imposing health risks on higher trophic levels. The aim of this study was to investigate the spatial distribution of fluoride in cultivated and uncultivated soils and the effects of farming practices on fluoride availability and distribution along the slopes of Mount Meru – a volcanic mountain.

The study area lies in the rift valley zone and its waters is largely used for irrigated agriculture (horticultural crops) is rich in fluoride. Samples from cultivated land were collected from smallholder farms and samples from uncultivated land were collected from Arusha National Park. Soil and water samples were randomly collected from the study area and were analyzed for fluoride content. Results indicate that concentration of fluoride in water and soil samples are higher for cultivated land when compared to uncultivated land. Research is however, ongoing to understand the magnitude of contamination and distribution of fluoride along the landscape.