Geophagic Clayey Materials of Sabga Locality (North West Cameroon): Genesis and Medical Interest

Abstract

Geophagia, the deliberate ingestion of clayey materials, is a complex eating behaviour with obscure etiology and numerous health/medical problems. Geological, mineralogical and geochemical studies were carried out on Sabga geophagic clayey materials located within a trachyte Bamenda mountain, about 16 km east of Bamenda town (North West Cameroon), in order to define the genesis, and its medical interest. Four (04) samples were characterized by different techniques: description of outcrops and pits, particle size distribution by laser dispersion, X-ray diffraction, Fourier transform infrared spectrometry, Scanning electron microscopy and bulk chemical analyses. The main clay minerals were smectite (49-60%) and kaolinite (4-6%). The other major minerals are quartz (19-34%), feldspar (6-12%), goethite (3-6%), and hematite (1-3%). The average particle diameter varied from 2 to 9 µm. Results from the different analytical techniques point out a meteoric weathering of feldspar as petrogenetic origin of geophagic clayey materials. Smectite and kaolinite, which are the main desirable minerals components of the geophagic clayey materials, were geochemically derived from surrounding trachytes. However the presence of crystalline silica (quartz) up to 2% limits the application of some Sabga geophagic clayey materials for pharmaceutical clays. The high radioactive (Th, U), carcinogenic (Cr, Cu, Pb, Ni) and teratogenic (or birth defects) (Cu, Zn, Pb) elements contents in some Sabga geophagic clayey materials implied some pretreatment.

Elemental Composition and Physicochemical Properties of Geophagic Clay (‘Eko’), From Ubiaja in Edo State, Nigeria

“…It is difficult to assess the proper dosage of the different components in geophagic materials; as a result, it is easy to consume excessive quantities of valuable minerals as well as dangerously large amounts of harmful or toxic materials, resulting in electrolyte imbalances and toxicity (Chamy et al, 2022). For example, one of the consequences of lead exposure, which has been found in some geophagic clay, is intelligence decline in exposed children, while in adults it can cause cancer over time (Kalguem et al, 2019;Olajide-Kayode et al, 2023). Another element of interest is zinc (Zn), which is generally considered non-toxic, but exposure to high concentrations can cause detrimental health effects such as growth retardation in infants, abdominal pain, diarrhea, and electrolyte imbalance (Ncube et al, 2020).…”

Geophagic Clays from Cameroon: Provenance, Metal Contamination and Health Risk Assessment

“…Several studies have been carried out on geophagic clays in Cameroon [13,[26][27][28][29][30][31][32][33]. In 2002, the European Commission alerted the Cameroonian Ministry of Public Health [27] about abnormally high amount of lead (100 times higher than the maximum permissible level) in geophagic kaolin carried from Cameroon to Europe.…”

“…In 2016, the study by Frazzoli et al [27] indicated that geophagic clays sold in markets in Cameroon contained high concentrations of lead, cadmium and mercury. Kenne Kalguem et al [32] also noted that geophagic clays from Sabga (Northwest Cameroon) contain high radioactive (Th, U), carcinogenic (Cr, Cu, Pb, Ni) and teratogenic (Cu, Zn, Pb) elements. Frazzoli et al [27] recommended that provenance studies of geophagic clays in Cameroon be carried out to establish environmental characteristics of these clays.…”