| Abstrakt: |
Environmental geology of a tar sand-rich area in parts of Southwestern Nigeria was carried out to generate geological baseline information necessary for the planning of exploitation of the deposit. This present project was aimed at evaluating the presence and concentrations of some geochemical elements in the Nigerian tar sands deposits in the eastern part of Dahomey Basin. The geochemical analysis of 10 representative samples of the tar sands was carried out using the Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) technique with the aid of Perkin Elmer ELAN 6100 instrument. Results of the analyses showed presence of the following trace elements As, Cd, Cr, Cu, Ni, Pb and Zn while radio active elements observed included Zr, Pb, Sr and U. Trace elements concentrations in the tar sands show a range of 5-90 ppm for V, 2.3-58.5 ppm for Cr, 4.1-331 ppm for Ni, 4 - 33.7 ppm for Zn, 0.2-2 ppm for As, 1.4-36.6 ppm for Pb, 0.8-54.3 ppm for Cu. The radio elements concentrations in the tar sands showed a range of 0.1-4.2 ppm for U, 0.4-18.9 ppm for Th, 1.4-36.6 ppm for Pb, 2.4-138 ppm for Sr, 1.3-24.1 ppm for Rb, 3-26 ppm for Zr. Generally, the concentrations of these geochemical elements were found to be less than the standard values. However, radioactive elements such as U, Th, Sr had values above normal standard at some of the locations. Radio elements like Pb show a positive correlation with U and Th implying that most of the Pb may be daughter cells of the U and Th decay. Based on these results, the Nigerian tar sand deposits in the study area can be said to be unpolluted by these elements except in few locations where higher values of radio elements were recorded. [ABSTRACT FROM AUTHOR] |
