Abstract
This study was conducted to examine the physical, chemical, mineralogical, geotechnical and phytochemical properties of the Edible clay materials from Aforwa, Ubiaja, Uzalla (Benin), Ohordua, (Edo state) and Achalla (Anambra State) in order to determine the potential human health risk as well as beneficial effect associated with their consumption and cosmetic use. From the geochemical data obtained by X-RF, SiO2 (54.64, 55.70, 45.70, 46.88 and 54.95%), and Al2O3 (27.90, 29.20, 35.20, 36.56 and 26.40%) are the dominant oxides indicating that the samples are basically hydrous Alumino-silicate. Calculated chemical index of alteration (CIA) and chemical index of weathering (CIW) of the clay samples ranges from 89.61 % in Achalla to 95.18% in Ohordua and 92.63% in Achalla and 99.32% in Ohordua respectively. This indicates a high degree of weathering of the clay samples. The clay minerals present from X-RD are Aforwa (Illite-smectite, Illite-muscovite), Ubiaja (Illite-muscovite and Kaolinite), Uzalla (chlorite, illite-smectite and illite- muscovite), Ohordua (Smectite, Illite-mica, Kaolinite and other clay minerals) and Achalla (Illite-smectite, and kaolinite). Most of the clays are interlayered clays. Mineral impurities in the clays are; quartz, jarosite, albite, anatase, orthoclase, microcline, hematite, calcite, pyrite, and gypsum. Colour ranges from light gray to brown in Achalla raw and smoked and white to strong brown in Uzalla raw and smoked respectively. Ohordua and Aforwa were gray and light gray.
