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The existence of large deposit of crude oil in the Nigerian Niger-Delta accords the region a strategic position in the country’s economy. However, activities associated with the oil and gas industry have resulted in extensive and in some instances indelible damages on the ecosystems. The destructive effect of hydrocarbon on bionetwork necessitated this study that aimed at evaluating the potential of adopting microbial and biosurfactant technology as tools for bioremediation. The research involved gas chromatography monitoring of hydrocarbon degradation in polluted soil, microbiological/molecular identification of hydrocarbon degraders and the evaluation of biosurfactant production by indigenous bacteria. The performance of four treatments involving; co-treatment with mixed bacterial consortium and close-to-nature surfactants (Bioversal QF and Bioversal UK), treatments with mixed bacteria culture, single bacteria culture and treatment with close-to-nature surfactants only were evaluated for the mineralization of hydrocarbons contained in 500g of 2% crude oil contaminated soil supplemented with Na2HPO4*2H2O, KH2PO4 and NH4Cl as nutrient sources over a period of 20 weeks. Six indigenous biosurfactant producing and/or hydrocarbon degrading bacteria strains were isolated namely: Pseudomonas aeruginosa, Bacillus sp, Achromobacter sp, Stenotrophonas sp, Lysinibacillus sp. and Delftia sp. Molecular characterization of sequenced polymerase chain reaction products of these cultured bacteria using Nucleotide Basic Local Alignment Search Tool confirmed close relationships ranging from 98.83% to 100% with those on the NCBI databank. Co-treatment with mixed bacteria culture and Bioversal UK/Bioversal QF yielded synergetic impact that enhanced 73.35% and 71.52% degradation of total petroleum hydrocarbon respectively. Treatments with close-to-nature surfactants and with mix bacterial culture recorded 53.61% and 54.58%. The use of single bacteria strains resulted in the mineralization of 46% - 62.26% total petroleum hydrocarbon while their use as a consortium yielded 54%. Liquid chromatography-Mass spectrometry assessment of extracellular polymeric substances produced by cultured bacteria strains indicated the presence of rhamnolipids (L-rhamnosyl-3-hydroxydecanoyl-3-hydroxydecanoic acid with a mass of 504.654 Da) and lipopeptides (2-(Hydroxymethyl) phenyl 6-O-palmitoyl-β-D-glucopyranoside with a mass of 524.687 Da). Extracellular polymeric substances produced yielded emulsion index ranging from 70.70% to 75% and 39% to 65% with crude oil and heptane respectively. EPS yields ranging from 1.34 g/ml to 1.5 g/ml were recorded.
This study investigates the applicability of remote sensing in general and imaging spectrometry in particular, for contaminated site detection and investigation with a focus on fuel hydrocarbon soil contaminations. Laboratory experiments were conducted to investigate the reflectance spectra of typical contaminants, contaminants at typical concentrations in soils, related materials and detection limits in a range of wavelengths from 0.38 µm to 2.5 µm. Characteristic absorption features of different organic chemicals, natural and man-made materials are described. Detection limits for fuel hydrocarbon contaminants in soils are defined, and the separability of hydrocarbon soil contaminations from other hydrocarbon-bearing materials is described. Data interpretation experiments using an imaging spectrometry dataset were conducted to assess the applicability of established data interpretation algorithms and to develop a method of detecting and separating different classes of hydrocarbons in imaging spectrometry datasets.
Im Rahmen der Arbeit werden nutzungs- und standortspezifische Hintergrundwerte für organische Schadstoffe (PAK, BaP und PCB) in Brandenburger Oberböden abgeleitet. Dabei wird der Medianwert im Sinne eines Hintergrundwertes, der den Normalzustand beschreibt, verwendet. Das 90er Perzentil charakterisiert eine den Normalzustand überschreitende Schadstoffkonzentration und fungiert als Referenzwert. Um den Transfer von PAK und PCB vom Boden in die Pflanze zu ermitteln, wurden Gefäßversuche mit für Brandenburg typischen Böden und Kulturen sowie Erhebungsuntersuchungen auf landwirtschaftlichen Flächen ausgewertet. Geprüft wurde der Schadstofftransfer in die Fruchtarten Mais, Kartoffel, Möhre, Salat, Spinat, Gras und Weizen. Festzustellen war, dass sich der PAK- und PCBTransfer in die Pflanze unter den Bedingungen der relativ leichten und schlecht mit organischer Substanz versorgten Böden des Landes Brandenburg auf niedrigem Niveau bewegt.