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There is a need for sustainable approaches in the remediation of hydrocarbon (HC)-impacted environments. Bioremediation has gained prominence but to be effective this requires consideration of the physical, chemical and biological processes in an environmental matrix. In the first part of this study, physical constraints to effective bioremediation of drill cutting (DC) were quantified using slurry-phase treatments. The DC:water ratio and aeration of the DC slurries were optimised. Results indicated that physical parameters, unless effectively managed, could greatly influence the performance of bioremediation campaign, both in terms of end-point and duration. Once physical aspects have been addressed, it is important to understand both chemical and biological processes. There has been a great deal of work considering the significance of chemical processes such as bioavailability, pH performance range and nutrient optimisation. These were not investigated in this programme of research. Bioaugmentation (microbial seeding of contaminated soils) has been proposed as a significant method for bioremediating HC-contaminated matrices. However, the value of bioaugmentation has been the subject of considerable controversy. The performance of bioaugmentation was studied in this project both directly and indirectly. Compounds capable of encouraging the activity of HC degraders were added to media. This "conditioning" process was investigated and quantified in three major experiments. Firstly, the conditioning of a HC-degrading bacterial consortium using selective enrichment substrates was studied. Here, INT reduction was monitored over time using 96-well microplates containing mineral media supplemented with diesel, toluene, hexadecane and phenanthrene. The colour development resulting from conditioning on different substrates varied significantly (P≤ 0.05). Secondly, the performance of HC degraders (Pseudomonas putida F1 and it's bioluminescent derivative, P. putida TVA8) after conditioning on a range of catabolic inducer substrates was studied. The development of an optimised experimental procedure to study carbon transformation of toluene as a consequence of conditioning was reported. Cultures conditioned on toluene had significantly (P≤ 0.05) higher activity, biomass and toluene degradation rates than the other treatments. Finally, the effect of conditioning three HC-degrading bacteria (Pseudomonas putida NCIMB 9816, Pseudomonas sp. and Klebsiella sp.), individually and in combination, on degradative performance and relative species abundance was assessed. DGGE profiles indicated significant (P≤ 0.05) changes in relative species abundance but, generally, there were no significant differences in HC degradation or cumulative respiration. The results reported in this thesis, at the genotypic, phenotypic and functional levels reveal the complexity of HC remediation and the need to combine detailed analytical chemistry with focussed microbial measurements.

The works carried out in this thesis exploited the application of nutrients and microbial additions to environments to enhance natural attenuation of petroleum hydrocarbon contaminant. These sites include former historically site contaminated with solvents [benzene, toluene, ethylbenze, xylene (BTEX)], an intertidal location at the Aberdeen Harbour polluted with diesel, a location at the periphery of the Burgan oil field in Kuwaiti desert contaminated with crude oil, and drill cuttings from the North Sea that was contaminated with paraffin and diesel. The effect of the treatments on the parameters tested was used to determine the performance of natural attenuation in studied environments. The parameters tested include respiration (carbon dioxide production), microbial dehydrogenase activity, microbial population and biomass, bioavailability of contaminants and toxicity testing. In addition, results from gas chromatography (GC-FID) and high performance liquid chromatography (HPLC) complemented biological tests. The treatments resulted in significant changes in the parameters tested and by correlating the observations to the reduction of total petroleum hydrocarbons (TPH) in the environments studied, the success of natural attenuation and bioremediation was confirmed. Techniques were manipulated to suit individual case studies. In response to nutrient and oxygen enhancement of the BTEX contaminated soil, the biomass of degradative microbial population was significantly stimulated. Results of significant increases in respiration and dehydrogenase activity coincided with completed biodegradation of BTEX in the soil. Oxygen that was released from hydrogen peroxide was found to be very effective in achieving significant biodegradation of benzene and toluene when combined with nitrogen and phosphorus. This could have implications for bioremediation of these compounds as the cost of oxygen supply becomes expensive. The bioavailability of BTEX compounds in the soil studied was successfully demonstrated by the used of Pseudomonas putida TVA8 biosensor, a sensor specific to these target molecules. It was observed that concentrations of BTEX that were not detected by HPLC were sensed by the biosensor. The bioremediation of North Sea drill cuttings contaminated with paraffin and diesel was achieved by nutrient additions and inoculation with soil microorganisms. Pre-treatment with steam was observed to be most effective in enhancing the biodegradation of paraffin oil contaminated drill cuttings, while pre-treatment with combined steam and ozone was most effective for enhancing biodegradation of paraffin and diesel contaminated drill cuttings. The metabolic biosensor Saccharomyces cerevisiae W303-1B (lucD) was more sensitive to water extracts of the drill cuttings than Escherichia coli HB101 (pUCD607), suggesting the use of the yeast biosensor in toxicity testing in cases requiring stricter treatment regime.

Chlorinated aliphatic and aromatic hydrocarbons are major pollutants resulting from their widespread use. In this project, one contaminant from each major group, namely trichloroethene and benzene, were studied in a shallow and deep aquifer, respectively. The shallow aquifer contaminated with trichloroethene and other chlorinated aliphatic hydrocarbons was too toxic for microbial processes. Several remediation technologies were investigated in laboratory studies, which were sparging, charcoal adsorption and the injection of chemical oxidants (Fenton's reagent and potassium permanganate). Each of these technologies on its own was found not to be suitable for the present site. The deep anaerobic aquifer contaminated with benzene was considered for enhanced natural attenuation. Despite the lack of constraints for anaerobic benzene degraders, no clear evidence for their presence was found. This was partly explained by a small biomass and aquifer variation as benzene was degraded under field conditions at low rates. The low degradation rates could not be observed in laboratory experiments so that an aerobic enhancement option in the form of hydrogen peroxide and/or nitrate injection was further investigated. Only the addition of hydrogen peroxide was demonstrated to be successful in reducing benzene concentrations. A direct transfer of the treatment to the field was considered unlikely due to the highly reducing in situ conditions. It was concluded that (enhanced) natural attenuation was unviable for both sites. Alternative remediation technologies considered at the respective sites were also found unsuitable based on laboratory results and aquifer properties. The luminescence-based bacterial biosensors provided a valuable tool for the evaluation of contaminant toxicity/bioavailability and the suitability of possible remediation strategies.

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A new method for the analysis of alcohol ethoxylates (AEs) using liquid chromatography with electrospray ionisation mass spectrometry (LC/ESI-MS) is described. The procedure in. corporates a novel derivatisation step with phthalic anhydride for the analysis of E00_,o ethoxylates in a single analysis. The derivatives obtained have proved to be very stable and the negative ion spectra show reduced background ions and competing adduct formation as compared to positive ion spectra. An automated solid phase extraction (SPE) step is used to allow both pre- concentration and clean-up of the environmental samples. The addition of 40 % v/v methanol prior to loading samples provides more efficient recovery of AEs across the C12 to C18 range than previously reported in the literature, reducing hydrophobic losses. Recoveries from final effluent spiked at 100 pg/L total AE, for the 126 species analysed, were found to be in the range 55 — 117%, with approximately 100 of the individual analytes having recoveries of 90 —105 %. A method detection limit of 0.02 iig/L for individual ethoxylate components is reported with the instrument operated in scan mode over the range m/z 300 to 1300. The method was applied to sewage effluent and influent samples, with AEs determined at approximately 7 and 5000 µg/L, respectively, indicating efficient removal of AEs in the sewage treatment plant. The AEs in the final effluent consisted primarily of fatty alcohols (FAs). Similar optimisation in the extraction of sediment and sludge samples was carried out with ultrasonic, Soxhlet and accelerated solvent extraction (ASE) methodology being compared. The most efficient technique was ASE, which was then used to analyse an activated sludge sample, where again. significantly high levels of FAs, compared to other AEs, were found in the sample. This data and the final effluent data are consistent with other current monitoring data for AEs and show the importance of a method capable of extracting and ionising the free alcohol efficiently. The AE fingerprint during biodegradation studies was also accurately determined giving elucidation of mechanisms of primary degradation. Linear and branched AEs were investigated with metabolite identification also carried out for the linear AE. Biodegradation of native AEs present in sewage influent was also studied in direct discharge scenarios to aid in. risk assessment in situations where sewage treatment is absent.

Σκοπός της παρούσας εργασίας είναι η εκτίμηση των περιβαλλοντικών συνθηκών στο Νομό Χαλκιδικής όσον αφορά τα Βαρέα Μέταλλα. Αυξημένες συγκεντρώσεις βαρέων μετάλλων εντοπίζονται ΒΑ του Νομού Χαλκιδικής λόγω της μεταλλευτικής δραστηριότητας. Η ποιότητα του περιβάλλοντος καθορίζεται από την γεωχημεία της περιοχής (λόγω της θειούχου μεταλλοφορίας) και από τον τρόπο που ασκήθηκε η μακρόχρονη δραστηριότητα στο παρελθόν, με τις μεθόδους εξόρυξης και τη συσσώρευση μεταλλευτικών υλικών χωρίς κανένα μέτρο προστασίας. Επίσης, δυτικά του Νομού Χαλκιδικής σημειώνονται αυξημένες συγκεντρώσεις Αρσενικού λόγω του γεωθερμικού πεδίου. / The main purpose of the dissertation is the estimation of the environmental conditions in the prefecture of Halkidiki, regarding the heavy metals. In the North East area of Halkidiki there are observed increasing concentrations of heavy metals because of the high metal activity of the area. The quality of the environment is determined from the geochemistry of the area (because of the sulfur ore) and from the way that the metal activity is implemented in the area, with the excavation methods that took place in the mining and the concentration of metal materials without specific protection measures. Also, in the West area of Halkidiki it is observed that the limit of arsenic in the ground and in the surface and underground waters has been exceed because of the geothermic field.