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The Biu Volcanic Province is one of the largest Volcanic Provinces in Nigeria covering an area of 5000 km2 with a thickness of 250m. Geochemical analysis of the volcanic soil revealed the complete leaching of the major elements (CaO, K2O, MgO, MnO, and TiO2) from the surface soil probably into water sources. This may explain the extremely high Ca and K levels especially in the stream water where they display values of 348mg/l and 36 mg/l as against 200mg/l to 12 mg/l respectively of WHO admissible limits for drinking water. The accumulation of transition metals in the soil (Co 84-111ppm; Cr: 230-441ppm); Ni: 169-237ppm) is geogenic derived from the weathering of the host basaltic rock. Cr, Ni, and Cu do not easily form soluble ions in solution explaining why they display lower levels below their respective WHO admissible limits for drinking water. The absence in the soil profile and the extremely higher values of potentially harmful elements (PHEs) (As, Se, Sb, and Pb) in the spring and stream water as opposed to the lower values in the wells and borehole water suggest their extreme solubility, direct leaching and transportation of these elements from the surrounding rocks into the surface water, which may be source of exposure to the inhabitants.

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Mr Adamu Usman Muhammad is an exploration Geologist with National Steel Raw Materials exploration Agency, Kaduna, Nigeria. He earned his First Degree in Geology from University of Maiduguri and Masters in Hydrogeology and Engineering Geology from University of Jos, Nigeria. He also earned an International e-learning course on Introduction to Remote Sensing Technology for Educators organised by Committee on Earth Observation Satellites (CEOS) and International Institute of Research, Brazil (INPE). Mr Usman is registered Geoscientists with council of Nigeria Mining Engineers and Geoscientists (COMEG). He is member Nigerian Mining and Geosciences Sciences Society (NMGS), Nigeria Association of Hydrogeologist (NAH), International Medical Geology Association (IMGA) and International Association of Geochemistry

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