Geophagic Clayey Materials of Sabga Locality (North West Cameroon): Genesis and Medical Interest
Earth Sciences
Volume 8, Issue 1, February 2019, Pages: 45-59
Received: Jan. 10, 2019; Accepted: Feb. 14, 2019; Published: Mar. 6, 2019
Views 99      Downloads 27
Authors
Elvis Duplex Kenne Kalguem, Department of Earth Sciences, Faculty of Sciences, University of Dschang, Dschang, Cameroon
Armand Sylvain Ludovic Wouatong, Department of Earth Sciences, Faculty of Sciences, University of Dschang, Dschang, Cameroon
Daniel Njopwouo, Department of Inorganic Chemistry, Faculty of Sciences, University of Yaoundé I, Yaoundé, Cameroon
Christel Sobdjou Kemteu, Laboratoire de Traitement Des Minerais, Institut De Recherches Géologiques Et Minières, Yaoundé, Cameroon
Georges Ivo Ekosse, Directorate of Research and Innovation, University of Venda, Thohoyandou, South Africa
Article Tools
Follow on us
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.
Keywords
Geophagic Clayey Materials, Meteoric Weathering, Sabga, Trachyte
To cite this article
Elvis Duplex Kenne Kalguem, Armand Sylvain Ludovic Wouatong, Daniel Njopwouo, Christel Sobdjou Kemteu, Georges Ivo Ekosse, Geophagic Clayey Materials of Sabga Locality (North West Cameroon): Genesis and Medical Interest, Earth Sciences. Vol. 8, No. 1, 2019, pp. 45-59. doi: 10.11648/j.earth.20190801.14
Copyright
Copyright © 2019 Authors retain the copyright of this article.
This article is an open access article distributed under the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
References
[1]
Abrahams, P. W., Parsons, J. A. (1996) Geophagy in the tropics: a literature review. Geogr. J., 162 (1): 63-72.
[2]
Aufreiter, S., Hancock, R. G. V., Mahaney, W. C., Stambolic, R. A., Sanmugadas, K. (1997) Geochemistry and Mineralogy of soils eaten by humans. Int J. Food Sci. Nutr., 48 (5): 293-305.
[3]
Banenzoue, C. (2017) Argiles consommées par géophagisme au Cameroun: Caractérisation physico-chimique, thermique et propriétés antiacide. Thèse de doc. 3e cycle, Univ. Yaoundé I, 187p.
[4]
Bhattacharya, P. T., Misra, S. R., Hussain, M. (2016) "Nutritional Aspects of Essential Trace Elements in Oral Health and Disease: An Extensive Review," Scientifica, vol. 2016.
[5]
Biscaye, P. E. (1965) Mineralogy and sedimentation of recent deep-sea clay in the Atlantic Ocean and adjacent seas and oceans. Geological Society of America Bulletin, 76, 803- 832.
[6]
Bloodworth, A. J., Highley, D. E., Mitchell, C. J. (1993) Industrial Minerals Laboratory Manuel: KAOLIN. BGS Technical Report WG/93/1. 76 pp.
[7]
Bloundi, M K. (2005) Etude géochimique de la lagune de Nador (Maroc oriental): Impacts des facteurs anthropiques. thèse de doctorat en co-tutelle en sciences de la terre et de l’univers. Université Mohamed V- Agdal, p 238.
[8]
Boski, T., Pessoa, J., Pedro, P., Thorez, J., Dias, J. M. A., Hall, I. R. (1998) Factors governing abundance of hydrolysable amino acids in the sediments from the N. W. European Continental Margin (47- 50°N). Progress in Oceanography, 42, 145-164.
[9]
Brand, C. E., De Jager, L., Ekosse, G. I. E. (2009) "Possible health effects associated with human geophagic practise: an overview," Medical Technology SA, vol. 23, pp. 11-13.
[10]
Braun, J. J., Pagel, M., Muller, J. P., Bilong, P., Michard, A., Guillet, B. (1990) Cerium anomalies in lateritic profiles. Geochim. Cosmochim. Acta 54, 781–795.
[11]
Braun, J. J., Viers, J., Dupré, B., Polve, M., Ndam, J., Muller, J. P. (1997) Solid/liquid REE fractionation in the lateritic system of Goyoum, East Cameroon: the implication for the present dynamics of soil covers of the humid tropical regions. Geochim. Cosmochim. Acta 62 (2), 273– 299.
[12]
Cook, H. E., Johnson, P. D., Matti, J. C., Zemmels, I. (1975) Methods of Sample Preparation and X ray Diffraction in X-ray Mineralogy Laboratory. Deep Sea Drilling Project, University of California, Riverside. Contribution n°74-5, 999-1007.
[13]
Carretero, I. M., Pozo, M. (2009) Clay and non-clay minerals in the pharmaceutical industry Part I. Excipients and medical applications. Applied Clay Science 46; pp. 73–80.
[14]
Chenyi, M. L. V. (2012) Volcanism and hydrochemistry of thermal and mineral springs in the Bambui Sabga area (North- West Cameroon). Higher Teachers Training Diploma (DIPES II) in Geology University of Bamenda. 61p.
[15]
Cravero, F., Dominguez, E., Iglesias, C. (2001) Genesis and applications of the Cerro Rubio kaolin deposit, Patagonia (Argentina). Appl. Clay Sci. 18, 157–172.
[16]
Dário, G. M., Da Silva, G. G., Gonçalves, D. L., Silveira, P., Junior, A. T., Angioletto, E., Bernardin, A. M. (2014) Evaluation of the healing activity of therapeutic clay in rat skin wounds. Mater. Sci. Eng, 43, pp 109–116.
[17]
Diko, M., Ekosse, G. I. E. (2014) Soil Ingestion and Associated Health Implications: A Physicochemical and Mineralogical Appraisal of Geophagic Soils from Moko, Cameroon. African Journal of Traditional Complementary and Alternate Medicine. Ethno Med, 8 (1): 83- 88.
[18]
Diko, M. L., Siewe, C. N. (2014) Physico- chemistry of geophagic soils ingested to relief nausea and vomiting during pregnancy. African Journal of Traditional Complementary and Alternate Medicine, 11 (3):21-24.
[19]
Dill, H. G., Fricke, A., Henning, K. H., Theune, C. H. (1995b) Aluminium Phosphate mineralization from the hypogene La Vanguardia kaolin deposit (Chile). Clay Miner. 30, 249– 256.
[20]
Dill, H. G., Bosse, H. R., Henning, K. H., Fricke, A. (1997) Mineralogical and chemical variations in hypogene and supergene kaolin deposits in a mobile fold belt The Central Andes of northwestern Peru. Miner. Depos. 32, 149–163.
[21]
Dill, H. G., Bosse, H. R., Kassbohm, J. (2000) Mineralogical and chemical studies of volcanic related argillaceous industrial minerals of the Central America Cordillera (Werstern Salvador). Econ. Geol. 95 (3), 517–538.
[22]
Douola Ninla, S. A., Wouatong, A. S. L., Tchounang Kouonang, S., Yerima, B., Njopwouo, D. (2018) Mineralogical and Physico-Chemical Characterization of Clayey Materials of Meka'a (West Cameroon) Preliminary Step for Their Utilization for Human Ingestion. Earth Sciences. 7 (2), 2018, pp. 74-85.
[23]
Ekosse, G. I. E., de Jager, L., Ngole, V. (2010) Traditional mining and mineralogy of geophagic clays from Limpopo and Free State provinces, South Africa. African Journal of Biotechnology, 9 (47): 8058 – 8067.
[24]
Ekosse, G. (2010) Kaolin Deposits and Occurrences in Africa: Geology, Mineralogy and Utilization. Applied Clay Science 50 (2): 212-236.
[25]
Ekosse, G., Jumbam, D. (2010) Geophagic clays: Their mineralogy, chemistry and possible human health effects. African Journal of Biotechnology Vol. 9 (40), pp. 6755- 6767.
[26]
Etakah Bate, E., Cheo Suh, E., Cottle, J., Ijunghi Ateh, K., Feudjio Tiabou, A., Anye Nche, L., Bih Che, V., Akumbom Vishiti. (2017) Petrology and geochronology of felsic volcanics in the Sabga area (Bamenda Highlands): implications for age variation along the Cameroon Volcanic Line. Journal of Geosciences, 62, pp 231–246.
[27]
Fagel, N., Boski, T., Likhoshway, L., Oberhaensli, H. (2003) Late Quaternary clay mineral record in Central Lake Baikal (Academician Ridge, Siberia). Paleogeography, Paleoclimatology, Paleoecology, 193, 159-179.
[28]
Fentaw, M. H., Menguistu, T. (1998) Comparison of Kombelcha and Bombowha kaolin of Ethiopia. Applied Clay Science 13, 149-164.
[29]
Finkelman, R. B., Centeno, J. A., Selinus, O. (2005) The Emerging Medical and Geological Association. T. Am. Clin. Climatol. Assoc., 116: 155-165.
[30]
Fontes, M. F. P., ldeu, A., Carvalho, J. I. A (2005) Color Attributes and Mineralogical Characteristics, Evaluated by Radiometry of Highly Weathered Tropical Soils. Soil Sci. Soc. Am J., 69: 1162-1172.
[31]
Gamiz, E., Delgado Calvo-Flores, G., Parraga, J., Delgado Calvo-Flores, R. (1989) Ann. pharmaceutiques française, pp 47, 33.
[32]
Grigsby, R. K., Thyer, B. A., Waller, R. J., Johnston, G. A. (1999) Chalk eating in middle Georgia: a culture-bound syndrome of pica? Southern Med. J., 92: 190–192.
[33]
Hajjaji, M., Kacim, S., Boulmane, M. (2001) Mineralogy and firing characteristics of clay from the valley of Ourika (Morocco). Applied Clay Science, 21, 203-212.
[34]
Harvey, C. C., Murray, H. H. (1997) Industrial clays in the 21st century: a perspective of exploration, technology and utilization. Appl. Clay Sci. 11, 285–310.
[35]
Höllriegel, V., Greiter, M., Giussani, A., Gerstman, U., Michalke, B., Roth, P., Oeh, U. (2007) Observation of changes in urinary excretion of thorium in humans following ingestion of a therapeutic soil. J. Environ. Radioactiv, 95: 149-160.
[36]
Hunter, J. M., De Kleine, R. (1984) Geophagy in Central America. Geogr. Rev., 74: 157–169.
[37]
Inoue, A. (1995) Formation of clay minerals in hydrothermal environment. In: Velde, B. (Ed.), Origin and Mineralogy of Clays: Clays and the Environment. Springer, Berlin, pp. 268–329.
[38]
IARC. (1997) Silica. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, IARC Scientific Publications, Lyon, France, 41 pp.
[39]
Juliana da Silva, F., Jonathan Parisotto, P., Valéria Weiss, A., Rosmary Nichele, B., Lucas Bonan, G., Carlos Pérez, B., Venina dos Santos. (2016) Physical and chemical characterization and method for the decontamination of clays for application in cosmetics. Appl. Clay Sci, p 8.
[40]
Kamgang, P., Njonfang, E., Chazot, G., Tchoua, F. (2007) Géochimie et géochronologie des laves des monts Bamenda (ligne volcanique du Cameroun). Comptes Rendus Geosciences, 339, 659- 666.
[41]
Kamgang, P., Njonfang, E., Chazot, G., Tchoua, F. (2008) Geochemistry and geochronology of mafic rocks from Bamenda Mountains (Cameroon): Source composition and crustal contamination along the Cameroon Volcanic Line. Comptes Rendus Geoscience, 340, 850-857.
[42]
Kamgang, P., Njonfang, E., Nono, A., Gountié, D. M., Tchoua, F. M. (2010) Petrogenesis of a Silicic Magma System: Geochemical Evidence from Bamenda Mountains, NW Cameroon, Cameroon Volcanic Line. Journal of African Earth Sciences, 58, 285-304.
[43]
Kenne Kalguem, E. D. (2013) Etude géologique et géotechnique des matériaux de Sabga-Bamessing (région du Nord- Ouest Cameroun): implication dans les risques naturels. Mémoire de Master des Sciences de la Terre de la Faculté des Sciences de l’Université de Dschang. 88p.
[44]
Kenne Kalguem, E. D., Wouatong, A. S. L., Njopwouo, D., Ekosse G. I. (2018) Physico-chemical Characterization of Clayey Materials Consumed by Geophagism in Locality of Sabga (North-western Cameroon): Health Implications. International Journal of Applied Science and Technology, 8 (3), pp 57- 68.
[45]
Ketcha, J., Gabche, S., Ndi, J., Maguie, A. (2011) Kinetic and equilibrium studies of the adsorption of lead (II) ions from aqueous solution onto two Cameroon clays: Kaolinite and smectite. Journal of Environmental Chemistry and Ecotoxicology Vol. 3 (11), pp. 290-297.
[46]
Lopez-Galindo, A., Viseras, C., Cerezo, P. (2007) Compositional, technical and safety specifications of clays to be used as pharmaceutical and cosmetic products. Applied Clay Science 36, 51– 63.
[47]
Mache, J. R., Signing, P., Njoya, A., Kunyu, F., Mbey, J. A., Njopwouo, D., Fagel, N. (2013) Smectite clay from the Sabga deposit (Cameroon): mineralogical and physicochemical properties. Clay Minerals, 48, 499-512.
[48]
Madejová, J., Komdel, P., Cicel, B. (1994) Infrared study of octahedral site populations in smectites. Clay Minerals, 29, 319-326.
[49]
Madejová, J. (2003) FTIR techniques in clay mineral studies. Vibrational Spectroscopy, 31, 1– 10.
[50]
Marian, A. N., Mavis, K., Godfred, D., Matt, D. (2016) Heavy metal content and potential health risk of geophagic white clay from the Kumasi Metropolis in Ghana. Toxicology Reports 3; 644–651.
[51]
Mascolo N., Summa V., Tateo F. (1999) Characterization of toxic elements in clays for human healing use. Applied Clay Science, 15, pp 491–500.
[52]
McDonough, W. F., Sun, S. S. (1995) The composition of the earth. Chemical geology 120, 223-253.
[53]
Merabet, D., Belkacemi, H. (2003) Caractérisation minéralogique et chimique du kaolin de Tamazert (Algérie). Ann. Chim. Sci. Mat. 28, 61–83.
[54]
Meunier, A., Velde, B., Dudoignon, P., Beaufort, D. (1983) Identification of weathering and hydrothermal alteration in acidic rocks: petrography and mineralogy of clay minerals. Sci. Géol., Mém. 72, 93–99 (Strasbourg).
[55]
Meyer, C., Hemley, J. J. (1967) Wall rock alteration. In: Barnes, H. L. (Ed.), Geochemistry of Hydrothermal Ore Deposits, pp. 167–235.
[56]
Mitchell, C. J. (1994) Laboratory evaluation of kaolin: a case study from Zambia. In: Whateley M. K. G., Harvey, P. K. (Eds.), Mineral Resource Evaluation II: Methods and Case Histories, Geol Soci. Special Publ., vol. 79, pp. 241–247.
[57]
Moore, D., Reynolds, J. R. (1997) X-Ray Diffraction and the identification and analysis of clay minerals. Oxford University Press, Oxford, 332p.
[58]
Murray, H. H., Keller, W. D. (1993) Kaolin, kaolin and kaolin. In: Murray, H. H., Bondy, W., Harvey, C. (Eds.), Kaolin Genesis and utilization. Special Publ., vol. 1. The Clay Miner. Soci., pp. 1 – 24.
[59]
Murray, H. H. (2000) Traditional and New Applications for Kaolin, Smectite, and Palygorskite: A General Overview. App. Clay Sci., 17, 5, 207-221.
[60]
Ndzie, E. M. C. (2009) Utilisation empirique des argiles brutes dans des pathologies digestives. (Observation de la ville de Dschang). Thèse de doctorat en médecine, 103 p.
[61]
Ngole, V. M., Ekosse, G. E. (2012) Physico-chemistry, mineralogy, geochemistry and nutrient bioaccessibility of geophagic soils from Eastern Cape, South Africa. Scientific Research and Essays Vol. 7 (12), pp. 1319-1331.
[62]
Nguetnkam, J. P. (2004) Les argiles des vertisols et des sols fersiallitiques de l’Extrême Nord Cameroun: Genèse, propriétés cristallographiques et texturales, typologie et applications à la décoloration des huiles végétales. Thèse Doc. D’Etat, Univ. Yaoundé I, 216P.
[63]
Njopwouo, D. (1984) Minéralogie et physico-chimie des argiles de Bomkoul et de Balengou (Cameroun). Utilisation dans la polymérisation du styrène et dans le renforcement du caoutchouc naturel. Thèse Doct. D'Etat, Univ. Yaoundé, Cameroun.
[64]
Njopwouo, D., Téjiogap, E., Sondag, F., Volkoff, B., Wandji, R. (1998) Caractérisations minéralogiques et chimiques des argiles consommées par géophagisme au Cameroun. Ann. Fac. Sci., Univ. Ydé I, 31 (2), 319-334.
[65]
Njoya, A., Nkoumbou, C., Grosbois, C., Njopwouo, D., Njoya, D., Courtin, N. A., Yvon, J., Martin, F. (2006) Genesis of Mayouom kaolin deposit (West Cameroon). Applied Clay Science, 32, pp 125-140.
[66]
Nkalih, M. A., 2016. Cartographie et propriétés physico-chimiques des argiles de Foumban (Ouest- Cameroun). Thèse Doc. D’Etat, Univ. Yaoundé I, 166P.
[67]
Nyakairu, G. W. A., Koebrel, C., Kurzweil, H. (2001) The Buwambo kaolin deposit in central Uganda: mineralogical and chemical composition. Chem. J. 35, 245–256.
[68]
Nyakairu, G., Koeberl, C. (2001) Mineralogical and chemical composition and distribution of rare earth elements in clay-rich sediments from central Uganda. Geochemical Journal, Vol. 35, pp. 13- 28.
[69]
Ossah, N. H. (1975) Altération des roches volcaniques dans les Monts Bamenda, Cameroun. Géologie, minéralogie et géochimie. Thèse Doct. 3e cycle, Univ. Paris VI, France.
[70]
Osredkar, J. (2012) "Copper and zinc, biological role and significance of copper/zinc imbalance," Journal of Clinical Toxicology, vol. 2013.
[71]
Petit, S. (1994) Hétérogénéité et variabilité de la composition chimique des minéraux argileux: à quelle échelle? Discussion de la notion de solution solide. HDR, Univ., Poitiers, France.
[72]
Poensin, D., Carpentier, P., Féchoz, C., Gasparini, S. (2003) Effects of mud pack treatment on skin microcirculation. Joint Bone Spine, 70, pp 367–370.
[73]
Prudêncio, M. I., Gouvela, M. A., Braga, S. M. A. (1995) REE distribution in present – day and ancient surface environments of basaltic rocks (central Portugal). Clay minerals, 30, 239 248.
[74]
Santos, M. C., Varajão, A. F., Yvon, J. (2004) Genesis of clayey bodies in Quadrilàtero Ferrífero, Minas Gerais, Brazil. Catena 55, 277–291.
[75]
Scherz, H., Kirchhoff, E. (2006) "Trace elements in foods: zinc contents of raw foods a comparison of data originating from different geographical regions of the world," Journal of Food Composition and Analysis, vol. 19, pp. 420-433.
[76]
Shanker, A., Venkateswarlu, B. (2011) "Chromium: environmental pollution, health effects and mode of action," Encyclopedia of environmental health, pp. 650-659.
[77]
Sheppard, S. C. (1998) Geophagy: who eats soil and where do possible contaminants go? Environ. Geol., 33 (2- 3): 109-114.
[78]
Soetan, K., Olaiya, C., Oyewole, O. (2010) "The importance of mineral elements for humans, domestic animals and plants-A review," African Journal of Food Science, vol. 4, pp. 200-222.
[79]
Tassongwa, B., Nkoumbou, C., Njoya, D., Njoya, A., Tchop, J. L., Yvon, J., Njopwouo, D. (2014) Geochemical and Mineralogical Characteristics of the Mayouom Kaolin Deposit, West Cameroon. Earth Science Research, 3 (1), 94 p.
[80]
Tassongwa, B., Eba, F., Njoya, D., Numbem, J., Jeudong, N., Nkoumbou, C., Njopwouo, D. (2017) Physico- chemistry and geochemistry of Balengou clay deposit (West Cameroon) with inference to an argillic hydrothermal alteration. Compte Rendu Geoscience 349, pp 212–222.
[81]
Todor, N. (1976) Thermal analysis of minerals. ABACUS Press, pp 224–225.
[82]
Tonle, I., Ngameni, E., Njopwouo, D., Carteret, C., Walcarius, A. (2003) Functionalization of natural smectite- type clays by grafting with organosilanes: physico-chemical characterization and application to mercury (II) uptake. Chem. Phys., 5, pp 4951–4961.
[83]
US Pharmacopeia. (2004) Bentonite, 27. US Pharmacopoeia Convention, Rockville, MD, p. 2826.
[84]
US Pharmacopeia. (2004b) Purified bentonite, 27. US Pharmacopoeia Convention Rockville, MD, pp. 2827–2828
[85]
USPC (United States Pharmacopoeial Convention). 1990c Bentonite. In: The National Formulary XVII. United States Pharmacopoeial Convention, Rockville, pp. 1902–1903.
[86]
USPC (United States Pharmacopoeial Convention). 1990d Bentonite magma. In: The National Formulary XVII. United States Pharmacopoeial Convention, Rockville, p. 1904.
[87]
USPC (United States Pharmacopoeial Convention). 1990e Purified bentonite. In: The National Formulary XVII. United States Pharmacopoeial Convention, Rockville, pp. 1903–1904.
[88]
USPC (United States Pharmacopoeial Convention). 1990f Magnesium aluminum silicate. In: The National Formulary XVII. United States Pharmacopoeial Convention, Rockville, pp. 1943– 1944.
[89]
Viseras, C., Cultrone, G., Cerozo, P., Aguzzi, C., Baschini, M. T., Valles, J., Lopez-Galindo, A. (2006) Characterization of northern Patagonian bentonites for pharmaceutical uses. Applied Clay Science, 31, 272-281.
[90]
Wang, Q., Zhao, H., Chen, J., Gu, K., Zhang, Y., Zhu, Y. (2009) "Adverse health effects of lead exposure on children and exploration to internal lead indicator," Science of the Total Environment, vol. 407, pp. 5986-5992.
[91]
WHO (World Health Organisation). (2008) "Guidelines for drinking-water quality electronic resource: Incorporating 1st and 2nd addenda, Vol. 1, Recommendations, Third editions".
[92]
Williams, L. B., Haydel, S. E. (2010) Evaluation of the medicinal use of clay minerals as antibacterial agents. Int. Geol. Rev., 52 (7-8): 745-770.
[93]
Worasith, N., Goodman, B. A., Neampan, J., Jeyachoke, N., Thiravetyan, P. (2011) Characterization of modified kaolin from the Ranong deposit Thailand by XRD, XRF, SEM, FTIR and EPR techniques. Clay Minerals, 46, 539–559.
[94]
Wouatong, G. A., Kitagawa, R., Takenos, Tchoua, F. M., Njopwouo, D. (1996) Morphological transformation of Kaolin minerals from granite saprolite in the Western part of Cameroun. Clay Sci. 10 (1), 67–81.
[95]
Wouatong, G. A. (1997) Mineralogical study of weathering on the Bana complex, west part of Cameroon. J. Sci. Hiroshima Univ., Ser. C II (1), 1–43.
[96]
Young, S. L. (2007) A vile habit ? The potential biological consequences of geophagia, with attention to iron. In: Mac Clancy J, Henry J, Macbeth H. eds. Consuming the Inedible: Neglected Dimensions of Food Choice. Oxford, United Kingdom.
ADDRESS
Science Publishing Group
1 Rockefeller Plaza,
10th and 11th Floors,
New York, NY 10020
U.S.A.
Tel: (001)347-983-5186