Groundwater fluoride levels in villages of Southern Malawi and removal studies using bauxite

Groundwater fluoride levels in villages of Southern Malawi and removal studies using bauxite

The extent of flouride presence in Malawi's groundwater reserves

Various natural and anthropogenic ecological factors pollute groundwater because of deep percolation from intensively cultivated fields, disposal of hazardous wastes, liquid and solid wastes from industries, sewage disposal and surface impoundments. Fluorides are one such type of contaminants that leach from
rocks and soils into ground water.Dental and skeletal fluorosis are known to be caused by excessive fluoride ingestion particularly from drinking water sources. Dental fluorosis is common in some parts of Malawi but studies on fluoride levels of drinking water sources have not been adequately done.

This paper presents the authors' findings in fluoride levels of some drinking water sources in selected rural areas of Southern Malawi and studies on the potential of locally sourced bauxite in water defluoridation at laboratory scale.

The study finds that:

  • the fluoride data at twenty-one of the forty-nine sampled locations was found to be above the WHO maximum limit of 1.50 mg/L
  • high levels of fluorides (>1.5 mg/L) exist in most villages in Nsanje district and in locations around Liwonde in Machinga district
  • laboratory experiments suggests that raw bauxite can be used for defluoridation to treat water in high fluoride areas.