Characterization of bitumen samples from four deposits in southwest, Nigeria using trace metals

Bitumen samples collected from different locations in south-western Nigeria were analysed for trace metal constituents such as Fe, Pb, Cu, Cd, Ni, Mn and V using Atomic absorption spectroscopy. The concentration of Fe ranged from 38.00 to 1537.00 ppm, Pb ranged from 11.00 to 27.00 ppm, Cu ranged from 3.00 to 10.00 ppm, Cd ranged from 4.00 to 15.00 ppm, Ni ranged from 9.00 to 62.00 ppm, Mn varied between 3.00 and 6.00 ppm, V ranged 10.00-150.00 ppm. Some ratios of these trace metals such as V/Ni, V/(V + Ni) and Fe/V were calculated, and the results show V/Ni ranged from 0.24 to 16.67, V/(V + Ni) varied from 0.20 to 0.94 and Fe/V ranged from 3.8 to 15.37. The low values of V/Ni ratios of samples AB, OI and IL suggest high maturity, mixed marine and terrestrial source of bitumen while the calculated values of V/(V + Ni) suggest that the samples were formed under oxic condition. The results were correlated using Pearson's correlation matrix. A high positive correlation among the four bitumen samples indicates that they are geologically and genetically related.