Physico-chemical Characterization of Clayey Materials Consumed by Geophagism in Locality of Sabga (North-western Cameroon): Health Implications
Kenne Kalguem Elvis Duplex, Wouatong Armand Sylvain Ludovic, Njopwouo Daniel, Ekosse Georges Ivo

Abstract
Geophagy is the habitual and intentional consumption of earth and clay deposits by animals and humans. Physicochemical properties of geophagic clayey materials from Sabga were determined in order to appreciate their capability to perform the functions for which they are consumed and possible consequences of the practice in humans. Among the properties investigated are: Tests conducted included colour, particle size distribution (PSD), consistency limits, pH, Electrical Conductivity (EC), Water Retention Capacity (WRC), Organic Matter Content (OMC) and Cation Exchange Capacity (CEC). Results show that the pH values range from 4.1 to 5.6. EC (0.01 to 0.02) and OMC values are low (3.99 to 5.10%). The WRC values are generally very high (above 50%). The samples were observed to have low CEC, ranging from 26.96 to 43.28. Geochemical data indicated that geophagic materials clayey are composed of SiO2 content ranging from 41.86% to 64.84%, Al2O3 values varies from 12.75% to 23.41%, Fe2O3 values varies from 4.14% to 13.29%, K2O content values varies from 0.28 to 2.43%, MgO content varies from 0.00% to 0.36%, CaO ranges between 0.04% and 0.56%, Na2O values varies from 0.10 to 1.78%, TiO2 values varies from 0.22% to 0.95%, P2O3 values varies from 0.02 to 0.05% and MnO content ranges from 0.01% to 0.12%. These values indicate that the geophagic clayey materials are essentially siliceous aluminosilicates. XRD revealed that geophagic clayey materials contain several minerals and the main reflections of the clay minerals identified were smectite and kaolinite. The peaks of other minerals are K-feldspars, plagioclases, hematite, goethite and quartz. The peaks of traces are ilmenite. The present studies have shown that the high clay content and the high water retention capacity may help to alleviate the symptoms of diarrhea because of its absorption ability. Because of the low CEC of the soils, adsorption of cations H+ from the stomach may not be possible for the relief of the gastric acidity. But from results of available elements, there is tendency for some of the cations to be released and absorbed into the gastrointestinal tract. Possible human health short coming in the ingestion of the geophagic clayey materials would include dental enamel damage and perforation of the sigmoid colon. These clayey soils, due to their colour are inferred to contain different forms of iron oxide minerals including hematite and goethite, which may help alleviate symptoms of iron deficiency anaemia.

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