Browsing by Author "Okparanma, R. N."

Now showing 1 - 5 of 5
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    Analysis of petroleum-contaminated soils by diffuse reflectance spectroscopy and sequential ultrasonic solvent extraction-gas chromatography
    (Elsevier Science B.V., Amsterdam., 2014-01-31T00:00:00Z) Okparanma, R. N.; Coulon, Frederic; Mouazen, Abdul Mounem
    In this study, we demonstrate that partial least-squares regression analysis with full cross-validation of spectral reflectance data estimates the amount of polycyclic aromatic hydrocarbons in petroleumcontaminated tropical rainforest soils. We applied the approach to 137 field-moist intact soil samples collected from three oil spill sites in Ogoniland in the Niger Delta province (5.317N, 6.467E), Nigeria. We used sequential ultrasonic solvent extractionegas chromatography as the reference chemical method. We took soil diffuse reflectance spectra with a mobile fibre-optic visible and near-infrared spectrophotometer (350e2500 nm). Independent validation of combined data from studied sites showed reasonable prediction precision (root-mean-square error of prediction ¼ 1.16e1.95 mg kg1, ratio of prediction deviation ¼ 1.86e3.12, and validation r2 ¼ 0.77e0.89). This suggests that the methodology may be useful for rapid assessment of the spatial variability of polycyclic aromatic hydrocarbons in petroleum-contaminated soils in the Niger Delta to inform risk assessment and remediation.
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    Bio-remediation of a sludge containing hydrocarbons
    (Elsevier, 2007) Ayotamuno, M. J.; Okparanma, R. N.; Nweneka, E. K.; Ogaji, S. O. T.; Probert, S. D.
    Bio-augmentation has been used as a bio-remediation option for hydrocarbon-contaminated, oily-sludge restoration. This sludge was obtained from the Bonny-Terminal Improvement Project (BTIP) for Bonny Island, near Port Harcourt, Nigeria. Its total hydrocarbon-content (THC) was 69,372 mg/kg of sludge. Three treatment reactors (X, Y and Z) and one control reactor (A) were charged with 1500 g of oily sludge and 250 g of agricultural soil (i.e. an oily sludge to soil ratio of 6:1), the mixture homogenized and allowed to settle for seven days before various CFUs were added to reactors X, Y and Z. Reactor A did not receive any bio-preparation. The agricultural soil served both as a nutrient and a microbe carrier. With regularly scheduled mixing and watering, the THC reduction in the oily sludge varied between 40.7% and 53.2% within two weeks as well as between 63.7% and 84.5% within six weeks of applying the bio-remediation. The CFU counts of the added bio-preparation varied between 1.2 × 1212 and 3.0 × 1012 CFU/g of sludge and decreased to 7.0 × 1011 CFU/g of sludge by the end of the sixth week. The pH of the degrading sludge fluctuated between 6.5 and 7.8 during the same period. When compared with the performance of the indigenous microbes in the control sample, the added bio-preparation evidently increased the THC reduction rate in the oily sludge.
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    Determination of Total Petroleum Hydrocarbon (TPH) and Polycyclic Aromatic Hydrocarbon (PAH) in Soils: A Review of Spectroscopic and Nonspectroscopic Techniques
    (Taylor & Francis, 2013-08-31T00:00:00Z) Okparanma, R. N.; Mouazen, Abdul Mounem
    In the analysis of petroleum hydrocarbon-contaminated soils for total petroleum hydrocarbons (TPHs) and polycyclic aromatic hydrocarbons (PAHs), the roles of spectroscopic and nonspectroscopic techniques are inseparable. Therefore, spectroscopic techniques cannot be discussed in isolation. In this report, spectroscopic techniques including Raman, fluorescence, infrared, and visible and near-infrared (Vis-NIR) spectroscopies, as well as mass spectroscopy (coupled to a gas chromatograph) and nonspectroscopic techniques such as gravimetry, immunoassay, and gas chromatography with flame ionization detection are reviewed. To bridge the perceived gap in coverage of the quantitative applications of Vis-NIR spectroscopy in the rapid determination of TPHs and PAHs in soils, a detailed review of studies from the period 1999-2012 are presented. This report also highlights the strengths and limitations of these techniques and evaluates their performance from the perspective of their attributes of general applicability, namely economic portability, operational time, accuracy, and occupational health and safety considerations. Overall, the fluorescence spectroscopic technique had the best performance (85% total score) in comparison to the others, and the gravimetric technique performed the least (60% total score). Method-specific solutions geared toward performance improvement are also suggested.
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    Rapid measurement of polycyclic aromatic hydrocarbon contamination in soils by visible and near-infrared spectroscopy
    (Cranfield University, 2013-10) Okparanma, R. N.; Mouazen, A. M.; Mayr, T.
    Polycyclic aromatic hydrocarbons (PAHs) are widely distributed organic pollutants. At petroleum contaminated sites, PAHs are often the key risk drivers because of their carcinogenicity. Assessing the risk of PAH at contaminated sites by conventional soil sampling, solvent extraction and gas chromatography–mass spectrometry (GC–MS) analysis is expensive and time-consuming. Employing a rapid and cheap measurement technique for PAH would be beneficial to risk assessment by eliminating costs and time associated with the conventional method. The literature has shown that visible and near infrared (vis-NIR) spectroscopy is a rapid and cheap technique for acquiring information about key soil properties. In this study, models based on vis-NIR spectroscopy (350–2500 nm) were developed to predict and map PAH in contaminated soils for the ultimate aim of informing risk assessment and/or remediation. The reference chemical analytical method used was GC–MS while the multivariate analytical technique used for model development was partial least squares (PLS) regression analysis with full cross-validation. A total of 150 soil samples from the UK were used for the laboratory-scale study while 137 samples were used for the near-onsite adaptive trials at three oil spill sites in Ogoniland, Niger Delta province of Nigeria. Both laboratory- and field-scale results showed that soil diffuse reflectance decreased with increasing PAH concentration. Hydrocarbon absorption features observed around 1647 nm in the first overtone region of the NIR spectrum showed a positive link to PAH. Laboratory-scale study showed that both individual and combined effects of oil concentration, and moisture and clay contents on soil spectral characteristics and calibration models were significant (p<0.05). For the field-scale study, inverse distance weighting soil maps of PAH developed with chemically-measured and vis-NIR-predicted data were comparable with a fair to good agreement between them (Kappa coefficient = 0.19–0.56). Hazard assessment of the oil spill sites using both measurement methods showed that the impact of the contamination varied distinctly across the management zones. The type of action required for site-specific risk assessment and/or remediation also varied among the different zones. This result shows promise that vis-NIR can be a good screening tool for petroleum release sites.
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    Visible and near-infrared spectroscopy analysis of a polycyclic aromatic hydrocarbon in soils
    (Hindawi Publishing Corporation, 2013-11-29) Okparanma, R. N.; Mouazen, A. M.
    Visible and near-infrared (VisNIR) spectroscopy is becoming recognised by soil scientists as a rapid and cost-effective measurement method for hydrocarbons in petroleum-contaminated soils. This study investigated the potential application of VisNIR spectroscopy (350–2500 nm) for the prediction of phenanthrene, a polycyclic aromatic hydrocarbon (PAH), in soils. A total of 150 diesel-contaminated soil samples were used in the investigation. Partial least-squares (PLS) regression analysis with full cross-validation was used to develop models to predict the PAH compound. Results showed that the PAH compound was predicted well with residual prediction deviation of 2.0–2.32, root-mean-square error of prediction of 0.21–0.25 mg kg−1, and coefficient of determination () of 0.75–0.83. The mechanism of prediction was attributed to covariation of the PAH with clay and soil organic carbon. Overall, the results demonstrated that the methodology may be used for predicting phenanthrene in soils utilizing the interrelationship between clay and soil organic carbon.