Textural and mineralogical characteristics of soils from selected geophagic mine sites in Cameroon and South Africa

Abstract

The deliberate ingestion of soil has commonly been defined by the generic term geophagia. However, soil is a very dynamic component and displays variable physico-chemical, mineralogical and geochemical properties. Upon ingestion, the positive and/or negative health effects would vary according to these inherent soil characteristics. In this study, soils from two geophagic mine sites at Ediki (Cameroon) and Duthuni (South Africa) have been texturally and mineralogically characterised. Based on results from particle size distribution (PSD) analysis, X-ray diffractometry and Fourier transform infra-red (FTIR) spectroscopy, soil samples from both study areas were described as silt loam, with the following mineralogical assemblage; quartz + kaolinite ± mica + microcline + goethite ± hematite + anatase + ilmenite. Quartz was a major constituent in all samples whereas kaolinite occurrence was variable (as major or minor constituent). The observed enrichment in silt fraction and quartz content may present risks of sand impaction with possible deleterious consequences such as destruction of dental enamel or perforation of the gastrointestinal (GI) lining of geophagic individuals.

Keywords:

• Quartz
• gritty texture
• geophagic individuals
• health risk
• sand impaction

ACKNOWLEDGEMENT

Funding from the UNESCO/IUGS/IGCP 545 Project on Clays and Clay minerals in Africa is acknowledged.