Excerpt
Inhalt
Abstract
1.0 Introduction:
2.0 Method of Study
3.0 Results and Discussions:
Conclusion
References.
HYDROCHEMISTRY OF WATER FROM SOME VILLAGES IN ALKALERI LOCAL GOVERNMENT AREA, BAUCHI STATE, NIGERIA
T. P. Bata[1], N.K. Samaila[1], J.N.Jabbo[2] and O.A. Solomon[3]
1. Department Geology, Faculty of Science and Technology, Abubakar Tafawa Balewa University Bauchi. Nigeria
2. Department of Geological Technology, School of Science and Technology, Abubakar Tatari Ali Polytechnic Bauchi. Nigeria
3. Department of Geology, Faculty of Natural Science, University of Jos. Nigeria
Abstract
Groundwater samples were collected from some villages in Alkaleri Local Government Area of Bauchi State. The samples were analyzed at the Geology Programme laboratory, Abubakar Tafawa Balewa University Bauchi. Concentration of iron, lead, manganese, chromium, calcium, copper, zinc and nickel were determined using the atomic absorption spectrometry (AAS). Results of the analyses show low values for iron, lead, manganese, calcium and copper in some locations (below the World Health Organizations (WHO) maximum permissible limit for drinking water). Concentrations of nickel and chromium in some locations are high (above the WHO maximum permissible limit for drinking water). Adequate concentrations of some of these trace elements in drinking water help in maintaining metabolism of the human body, however, higher or lower concentrations could have adverse effects on humans.
1.0 Introduction:
The area of study covers the villages of Gar, Panti, Badara, Vulum, Yashi and MainaMaji in Alkaleri Local Government of Bauchi State, which fall under the Gongola sub-basin of the Upper Benue Trough (see figure 1). This Gongola sub-basin is located NE of the Upper Benue Trough, and is a NNE-SSW trending rift about 800km long and 150km wide containing up to 6,000M of Cretaceous – Tertiary sedimentary rocks. The section pre-dating a mid-Santonian compressional phase has been folded, faulted and locally uplifted, resulting in over 1000 anticlines and synclines (Benkhelil, 1989). According to the works of Carter et al., (1963), the Bima sandstone is the earliest sedimentary rock deposited in the basin. The successive cretaceous rocks overlying the Bima in the Gongola sub-basin are divided in to the following formations which range in age from Cenomanian to Maastrichtian. Figure 2 below shows the stratigraphic descriptuion of the Benue Trough.
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Figure 1. Geologic Map of Nigeria (minimized) showing the study area. (Modified from Obaje 2009
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Figure 2. Stratigraphic Description of the Benue Trough.Adapted from Obaje (2000).
Groundwater in the study area occurs within the Paleocene Kerri-Kerri Formation. This is composed of poorly sorted sandstone with interstitial clays (Bata et al, 2009).
2.0 Method of Study.
A total of seventeen (17) ground water sample were collected from the study area. These samples were analyzed at the Geology Programme laboratory, AbubakarTafawaBalewa University Bauchi. Concentration of iron, lead, manganese, chromium, calcium, copper, zinc and nickel were determined using the atomic absorption spectrometry (AAS). The sample were digested first , by measuring 50ml of the water samples into the sample vapour, is illuminated by a light source calibrated beaker. Add 5ml of nitride acid (HNO3) and Hydrochloric acid (HCL) in the ratio of 3:2 (3ml of HNO3 + 2ML OF HCL). Heat the mixture on a hot plate until the volume is reduce to 10ml through evaporation and make it up to the mark in 50ml in volumetric flask with distilled water. Read the absorbance from Atomic Absorption Spectrophotometer (AAS), which will indicate the corresponding percentages for each traced element.
The Atomic Absorption Spectrophotometer (AAS) works on the principle that atoms in a flame at ground state (to be analyzed) absorb the same wavelength of light that will emit if exited. The sample is brought into solution. This solution is aspirated (dispersed or evaporated) by means of a flame (mixture of air and acetylene).which gives a temperature about 2000⁰c. This high temperature reduces the droplet into atomic form I.e. the element in solution are now in vapour and therefore in natural or unbound state. This condition is to be on ground state”. If higher temperature is needed to aspirate the solution, the flame would be made of mixture of nitrous oxide, and acetylene and it will give a temperature of up to 8000⁰c. The sample in vapour is illuminated by a light source which is the hallow cathode lamp (HCL) is the as the material to be analyzed e.g. for the analysis of (Zn, Pb, Ca, Cr, Mn, Ni, Cu, Fe,) HCL was used so that the atom in vapour absorb radiation from the HCL. This radiation is isolated by means of monochromoter. The radiation from the HCL is reduced because of the absorption of vapour and a detector measures it. The amount of absorption (intensity) is proportion to the concentration of the element in the sample (vapour), Hence, by measuring the decrease in energy received by the detector, the amount of the element in the sample can be established (Skoog, et al. 1992).
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Figure 3 Schematic diagram of atomic absorption spectrophotometer (after Skoog et al, 2009)
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