Biodegradation, water solubility and characterisation studies of unresolved complex mixtures (UCMs) of aromatic hydrocarbons
type: CreativeWork
description: Following release to the environment, crude oil becomes subject to weathering processes which remove the simple, volatile hydrocarbons leaving an unresolved complex mixture (UCM) comprising the more environmentally persistent components. Aromatic UCMs have been reported in a wide variety of environmental matrices. Recent studies indicate such material, particularly monoaromatic hydrocarbons, is sufficiently bioavailable to marine organisms (e. g. mussels) to elicit toxicological responses. However, little else is known about the environmental fate and composition of petroleum-derived aromatic UCMs. The overall aim of this work was to investigate aromatic UCMs with particular emphasis on their biodegradability, water solubility and composition. To assess persistence in the environment, an 'aromatic' UCM was isolated from Tia Juana Pesado crude oil (Venezuela) and this UCM exposed to the hydrocarbon degrading bacterium Pseudomonas fluorescens (Texaco). Five synthesised alkylcyclohexyltetralins and an alkylcyclohexylnaphthalene, proposed previously as 'average' structures for some aromatic UCM components, were also exposed under the same conditions. After 50 days, biodegradation of the compounds had not exceeded 20%, the most resistant (-2% biodegradation) being those with C3-C5 alkyl chains. These latter results were comparable to those observed for the 'aromatic' UCM (-2%). Using North Sea oil or n-hexadecane as co-substrates, the synthetic compounds were also exposed to a natural consortium of bacteria to provide more environmentally realistic conditions. After 119 days the branched chain C5 homologue (-60%) and the naphthalene (-12%) still remained, yet under these severe conditions the components of the North Sea crude oil co-substrate were extensively degraded with even the highly bioresistant pentacyclic hopanes exhibiting biodegradation. Aqueous solutions of an 'aromatic' and 'monoaromatic' UCM were produced (at 25 'C) using a generator column technique. These …
abstract: Following release to the environment, crude oil becomes subject to weathering processes which remove the simple, volatile hydrocarbons leaving an unresolved complex mixture (UCM) comprising the more environmentally persistent components. Aromatic UCMs have been reported in a wide variety of environmental matrices. Recent studies indicate such material, particularly monoaromatic hydrocarbons, is sufficiently bioavailable to marine organisms (e. g. mussels) to elicit toxicological responses. However, little else is known about the environmental fate and composition of petroleum-derived aromatic UCMs. The overall aim of this work was to investigate aromatic UCMs with particular emphasis on their biodegradability, water solubility and composition. To assess persistence in the environment, an 'aromatic' UCM was isolated from Tia Juana Pesado crude oil (Venezuela) and this UCM exposed to the hydrocarbon degrading bacterium Pseudomonas fluorescens (Texaco). Five synthesised alkylcyclohexyltetralins and an alkylcyclohexylnaphthalene, proposed previously as 'average' structures for some aromatic UCM components, were also exposed under the same conditions. After 50 days, biodegradation of the compounds had not exceeded 20%, the most resistant (-2% biodegradation) being those with C3-C5 alkyl chains. These latter results were comparable to those observed for the 'aromatic' UCM (-2%). Using North Sea oil or n-hexadecane as co-substrates, the synthetic compounds were also exposed to a natural consortium of bacteria to provide more environmentally realistic conditions. After 119 days the branched chain C5 homologue (-60%) and the naphthalene (-12%) still remained, yet under these severe conditions the components of the North Sea crude oil co-substrate were extensively degraded with even the highly bioresistant pentacyclic hopanes exhibiting biodegradation. Aqueous solutions of an 'aromatic' and 'monoaromatic' UCM were produced (at 25 'C) using a generator column technique. These …
author: Booth, Andrew Michael
language: eng
date published: 2004-01-01T08:00:00Z
date modified: 2026-07-24T03:49:27Z
provider: University of Plymouth
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Plymouth