scholarly journals Evaluation of Polycyclic Aromatic Hydrocarbons and Total Petroleum Hydrocarbons Profiles in Some Nigerian Crude Oils

2019 ◽  
pp. 1-14
Author(s):  
N. Boisa ◽  
T. J. K. Ideriah ◽  
C. S. Okehie
Keyword(s):  
Molecular Weight ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Crude Oil ◽  
Aromatic Hydrocarbons ◽  
Petroleum Hydrocarbons ◽  
Total Petroleum Hydrocarbons ◽  
Crude Oils ◽  
Low Molecular Weight ◽  
Polycyclic Aromatic ◽  
Pahs Concentration

Aim: To evaluate the concentrations of Polycyclic Aromatic Hydrocarbons and Total Petroleum Hydrocarbons in some Nigerian crude oils. Study Design: Field and Laboratory-Experimental Design were used in this study. Place and Duration of Study: Crude oil samples were obtained from three locations (designated as Location 1, Location 2, and Location 3) in the Niger Delta, Nigeria. Methodology: The samples were subjected to liquid-liquid extraction using dichloromethane and analysed using GC-FID. Results: The results of the analyses of the crude oils gave polycyclic aromatic hydrocarbons (PAHs) concentrations of 2.6089 x 104 ppm representing 60.06% and total petroleum hydrocarbon (TPH) concentration of 4.3201 x 104 ppm at Location 1, PAHs concentration of 4.764 x 103 ppm (62.8%) and TPH recording a concentration of 7.583x 103 ppm at Location 2, while Location 3 had PAHs concentration of 9.93 x 102 ppm (30.66%) and TPH concentration of 3.239 x 103 ppm. The total concentrations of the high molecular weight PAHs were lower than those of the low molecular weight PAHs in the samples. Also the concentrations of the individual PAHs were higher in the low molecular weight PAHs. The mean PAHs concentrations of 2707.6 ppm (location 1), 551.5 ppm (location 2) and 90.7 ppm (location 3) are different. Conclusion: The observed  results show that all the sixteen polycyclic aromatic hydrocarbons listed as priority pollutants are present in the three crude oil samples with higher concentrations in the light crude oils than in the heavy crude oil and a strong correlation with the total petroleum hydrocarbon concentration. It was also observed that though the ratios of the low molecular weight PAHs to high molecular weight PAHs of the crude oils indicate petrogenic, the unique diagnostic ratios suggest pyrogenic input. There is therefore the need to develop a method of PAHs removal from PAHs contaminated water based on locally available and cheap materials.

scholarly journals Assessment of Total Petroleum Hydrocarbons and Polycyclic Aromatic Hydrocarbons in Wastewater from Selected Flow Stations in Agbada II, Rivers State

2021 ◽  
pp. 31-40
Author(s):  
Akpan Esther Emmanuel ◽  
Obi Chidi ◽  
Kinigoma Boma
Keyword(s):  
Molecular Weight ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Petroleum Hydrocarbons ◽  
Total Petroleum Hydrocarbons ◽  
Polycyclic Hydrocarbons ◽  
Low Concentrations ◽  
Three Samples ◽  
Polycyclic Aromatic ◽  
Rivers State

Aims: This study evaluates total petroleum hydrocarbon (TPH) and polycyclic hydrocarbons (PAHs) concentrations in wastewaters from three locations of the oil-producing flow station in Rivers State. Study Design: By experiment and the results obtained by analytical means. Place and Duration of Study: This work was conducted at the Department of Industrial Chemistry/Petrochemical Technology, School of Science and Laboratory Technology, University of Port Harcourt, Choba, Rivers State, Nigeria between February and August, 2021. Methodology: The evaluation was done using gas chromatography-Flame Ionization Detector (GC-FID), and Gas Chromatography-Mass Spectrometer Detector (GC-MSD). Results: Results obtained showed low levels of total petroleum hydrocarbons ranging from 0.051, 0.119, and 0.07 mg/l and 0.01, 0.06, and < 0.01 mg/l for polycyclic aromatic hydrocarbons for the three locations, respectively. The results also revealed that the concentrations of the total petroleum hydrocarbons of the samples from the three locations were highest at carbon atom 17 suggesting a biogenic contribution of organic matter. The chromatographs obtained gave evidence that the nature of the contamination was minimally crude oil, because crude oil normally distributes in broad range, as observed in the locations samples as against the narrower carbon range of C8 to C40 characteristics of refined products. The pristane/phytane ratios, which were 0.925, 0.891 and 0.372 for the three samples, depicted an oxygenated environment. The C17/pristane ratios (39.53, 38.93, and 31.48) for all three locations revealed that the wastewaters were slightly weathered. The low concentrations as well as absence of high molecular weight polycyclic aromatic hydrocarbons and higher concentrations of low molecular weight polycyclic aromatic hydrocarbons support the petrogenity of the wastewaters.  The phenanthrene/anthracene ratios (1.26, 0, and 0) for the three samples confirm the nature of the wastewaters. In addition, the absence of benzo(a)anthracene to chrysene ratio for all three samples point to proper treatment of the wastewaters. Conclusion: From this study, the level of total petroleum hydrocarbons (TPH) and polycyclic hydrocarbons (PAHs) obtained from all the samples were lower than the maximum recommended levels by the Department of Petroleum Resources (DPR). This study recommends constant monitoring in the total petroleum hydrocarbons and polycyclic hydrocarbons concentrations because even at its low concentrations can be injurious to health of the people residing within the facility and beyond.

scholarly journals CYP63A2, a Catalytically Versatile Fungal P450 Monooxygenase Capable of Oxidizing Higher-Molecular-Weight Polycyclic Aromatic Hydrocarbons, Alkylphenols, and Alkanes

2013 ◽  
Vol 79 (8) ◽  
pp. 2692-2702 ◽  
Author(s):  
Khajamohiddin Syed ◽  
Aleksey Porollo ◽  
Ying Wai Lam ◽  
Paul E. Grimmett ◽  
Jagjit S. Yadav
Keyword(s):  
Molecular Weight ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Substrate Specificity ◽  
Crude Oil ◽  
Aromatic Hydrocarbons ◽  
Aliphatic Hydrocarbon ◽  
Ligand Docking ◽  
P450 Monooxygenase ◽  
Polycyclic Aromatic ◽  
Long Chain

ABSTRACTCytochrome P450 monooxygenases (P450s) are known to oxidize hydrocarbons, albeit with limited substrate specificity across classes of these compounds. Here we report a P450 monooxygenase (CYP63A2) from the model ligninolytic white rot fungusPhanerochaete chrysosporiumthat was found to possess a broad oxidizing capability toward structurally diverse hydrocarbons belonging to mutagenic/carcinogenic fused-ring higher-molecular-weight polycyclic aromatic hydrocarbons (HMW-PAHs), endocrine-disrupting long-chain alkylphenols (APs), and crude oil aliphatic hydrocarbonn-alkanes. A homology-based three-dimensional (3D) model revealed the presence of an extraordinarily large active-site cavity in CYP63A2 compared to the mammalian PAH-oxidizing (CYP3A4, CYP1A2, and CYP1B1) and bacterial aliphatic-hydrocarbon-oxidizing (CYP101D and CYP102A1) P450s. This structural feature in conjunction with ligand docking simulations suggested potential versatility of the enzyme. Experimental characterization using recombinantly expressed CYP63A2 revealed its ability to oxidize HMW-PAHs of various ring sizes, including 4 rings (pyrene and fluoranthene), 5 rings [benzo(a)pyrene], and 6 rings [benzo(ghi)perylene], with the highest enzymatic activity being toward the 5-ring PAH followed by the 4-ring and 6-ring PAHs, in that order. Recombinant CYP63A2 activity yielded monohydroxylated PAH metabolites. The enzyme was found to also act as an alkane ω-hydroxylase that oxidizedn-alkanes with various chain lengths (C9to C12and C15to C19), as well as alkyl side chains (C3to C9) in alkylphenols (APs). CYP63A2 showed preferential oxidation of long-chain APs and alkanes. To our knowledge, this is the first P450 identified from any of the biological kingdoms that possesses such broad substrate specificity toward structurally diverse xenobiotics (PAHs, APs, and alkanes), making it a potent enzyme biocatalyst candidate to handle mixed pollution (e.g., crude oil spills).

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