Mineralogical Profile of Geophagic Clayey Soils Sold in Selected South African Informal Markets

Abstract

Abstract-Geophagia, the intentional ingestion of clayey soil has both useful and negative health effects on humans due to the biomass, physicochemical, mineralogical and geochemical composition of the gritty material. In a few circumstances, clayey soil is viewed as a supplement to health deficiencies resulting from a less than stellar eating routine. Geophagy has been of interest to researchers and analysts due to continued habitual, religious and cultural practices by diverse communities globally in spite of reports contraindicating its purported benefits. The gritty material remains a thing of interest considering the nature in which they are obtained, transported and stored. Six geophagic clayey soil samples were obtained from chosen casual markets in South Africa. Four of these samples were originally from around South Africa and two were originally from Nigeria. The samples were analysed and characterised utilizing XRF, XRD, pH, and electrical conductivity to survey the nutritious qualities that support the continued use by mostly females and pregnant ladies in various parts of South Africa. Results of the XRD analysis revealed that the clay materials were mainly composed of kaolinite with minor palygorskite, illite, Amesite, Gupeite, Hematite and Magnetite. Quartz was the major non-clay constituent identified. Results of the XRF analysis showed average values of major elements such as SiO 2 (54.02%), Al 2 O 3 (35.45%), Fe 2 O 3 (6.73%), K 2 O (2.76%), MgO (1.16%) with MnO, Na 2 O and P 2 O 5 falling below 0.5%. Titanium was a major heavy metal identified from the samples which may result in heavy metal toxicity. The potential medicinal application of these clayey soils is supported by their kaolinite contents; in contrast the trace elements are pointers of probable adverse effects on humans.

Geophagic Materials Characterization and Potential Impact on Human Health: The Case Study of Maputo City (Mozambique)

“…The slight EC difference between unprepared and prepared near the mine samples may be associated with sieving once fine fractions are more conductive [54], while higher EC results in market samples may be the result of additives (e.g., NaCl) added to geophagic materials, to improve flavor. Other studies reported high EC values in geophagic materials with salt added, and that can be linked to diarrhea-causing enterotoxins absorption and to gastrointestinal epithelium protection [55].…”