Industrial activities and accidental releases often introduce a large amount of inorganic and organic contaminants to the environment. Humic substances interact strongly with metals and organic pollutants. In this study, this property was exploited in order to establish new remediation materials in two environmental applications and in one pharmaceutical application. The two remediation materials under investigation were sludge and sediment, ST sludge and CE sludge, respectively. The first application aimed at investigating the use of the remediation materials to remove arsenic, iron, and uranium from the industrial effluents. The main results were the release of iron from ST sludge inhibited its usage as remediation material whereas CE sludge showed excellent performance. The extractions were both rapid and efficient. The second application studied the extraction of organic contaminants. The objective of this study was to find a new remediation material for removal of organic contaminants. The remediation materials showed similar and excellent performance on extraction of chlorinated anilines, phenols and benzenes. The third application investigated the extraction of iodine species from urine. It aimed at determining whether the radioactive iodine can be extracted from the urine and thereby concentrated into a smaller volume of solid. Even though the extraction percentages from urine were not as promising as from deionised water and synthetic urine, scientific interest was raised and further investigations on the effect of the composition of urine and solubility of sludges for the extraction of iodine species were recommended. The outcome of the presented study was interesting both scientifically and economically. The promising extraction results for arsenic, iron and uranium indicate that the CE sludge is ready to be tested in a field study. The extraction of organic compounds by both remediation materials was also promising. However, further studies on permeability and solubility were recommended.

Organic reactions, which can be carried out in water and in the absence of heavy metals, are becoming more important today due to concerns over safety and environmental impact. Thus if an oxidation reaction can be carried out, where the oxidant is generated in-situ using electrolysis, then this is advantageous over existing systems that use strong or large volumes of stoichiometric oxidant and solvent, that cannot be recycled. In this thesis a wide variety of conditions and methods for producing enantiomerically enriched epoxides and sulfoxides have been reported using both electrochemically generated percarbonate and hypochlorite. It has been possible to carry out a range of oxidation reactions both as a one-pot reaction and with the oxidant generated in a batch process. Carrying out sulfoxidation reactions as a batch process with a carbonate solution it is possible to obtain ees of 20%. Using our in-situ generation of oxidant, as a one-pot electrochemical reaction, has provided a wide range of sulfoxides in good to excellent yield, with the application of this system to the oxidation of alkenes using a chiral iminium salt resulting in 100% conversion, with up to 44% ee.

Depleted uranium (DU) is a by-product of the nuclear fuel industry and is used in anti-tank penetrators due to its high density, self-sharpening and pyrophoric properties. Military activities have left a legacy of DU waste in terrestrial and marine environments and presently there are no clean up procedures in place. In order to understand the fate of this DU, long term (500 days) microcosm experiments simulating key environments have been carried out for the first time to investigate the mechanisms and rates of DU corrosion as a function of the biogeochemical and environmental conditions.

In urban areas, traffic is a major source of air pollution. Concentrations of pollutants are observed to be particularly high near ground level in street canyons, where tall buildings and different obstacles limit the ventilation. This impedes the dispersion of pollutants, contributing to build-up of harmful substances, which have an adverse effect on human health and comfort. Consequently, there is a desire to understand the mechanisms that contribute to street level ventilation especially in exploring the effect that heterogeneous layout of a street canyon has on the ventilation level. It has been established that extent of ventilation is dependent upon the background meteorological conditions, and how they interact with the building geometry. There is further interest in investigating the effect of the ambient conditions in heterogeneous street canyons. In the existent urban areas it is necessary to improve the ventilation for better comfort of the people who live in these areas and the surrounding environment. Elements that might exist in the street such as traffic lane position, parked cars or other obstacles may also have an effect on the distribution of pollutants or flow regimes. This thesis focuses on exploring the flow features and distribution of traffic-related pollutants in heterogeneous street canyons. Comparisons are made between symmetric and non-symmetric geometrical street layouts. In addition, this thesis examines the effect of local street parameters, such as the position of traffic lanes and the placement of parked cars, on the distribution of pollutants in heterogeneous, symmetrical and non-symmetrical canyons. A heterogeneous street canyon in Cyprus is used as a case study to examine the ventilation in these types of street canyons. This street was modelled in the lab, in a water channel, applying simultaneously the advanced imaging techniques of Particle Image Velocimetry (PIV) and Planar Laser Induced Fluorescence (PLIF). The same techniques were also applied to models of symmetrical and non-symmetrical canyons under constant perpendicular ambient conditions. A field measurement campaign was undertaken in the real heterogeneous street canyon in Nicosia to examine the flow fields and pollution distribution under variable ambient conditions and traffic flow rate. A comparison was made between the results obtained under constant and variable ambient conditions. The heterogeneity of the canyon was found to influence the distribution of pollutants at street level. The overall pollution levels are lower in the heterogeneous 4 street canyon than in symmetrical and non-symmetrical canyons. Flow fields are found to vary along the length of the heterogeneous street canyon and each cross section behaves individually according to its own geometric layout, leading to a different distribution of pollutants in each cross section. In addition, the existence of gaps (either only at the upstream side or both upstream and downstream side) is found to produce higher level of turbulence resulting in lower pollution levels near the ground level than can be expected for a symmetrical canyon. However, the existence of a gap only at the downstream side did not enhance the ventilation near the ground level at this side of the canyon. In this case the pollution levels were slightly higher compared to the locations along the length of the canyon where the gap was at the upstream or both sides. The local street parameters influence the distribution of pollutants near the ground level at all the examined street geometries. It was found that moving the traffic lane near the downstream area and the placement of parked cars on the upstream area produces major reductions of pollutants. The variability of the ambient wind was found in the field to produce different flow regimes compared to the case when the ambient flow was constant and perpendicular. At all the examined locations the flow was three dimensional. Despite this difference in the flow regimes the pollutants have similar distribution to those observed in the laboratory study. One possible explanation is that the local street parameters (such as the location of the traffic lane and the placement of parked cars in the street) had a greater impact at street level compared to the variability of the wind. Finally, results indicate that the recurrent, frequent variations in building heights along the length of the street contribute to significantly increase the dilution of pollutants near ground level, where the implications to pedestrian health and comfort are greatest.

An average of 3.5-4.5 million square km of vegetation burns in global wildfires each year. The gases and particulates released have substantial chemical and radiative impacts, the magnitude of which depends on the specific makeup and magnitude of the emissions. This research focuses on the development, evaluation and application of field-deployed methods based around Fourier transform infrared (FTIR) spectroscopy for the assessment of the emissions from biomass burning events. In particular, full assessment of the atmospheric effects of biomass burning generally requires spatio-temporally resolved data on the makeup and magnitude of the smoke emissions. This is usually obtained via multiplication of the amount of fuel consumed [M] by an emission factor [EFX], representing the amount of chemical species [x] released per kilogram of dry fuel burned. Emissions factors for many species typically show wide ecosystem variations, and also vary with meteorology and fire type, increasing the uncertainty in this important variable. When compared to established point-sampling methods, OP-FTIR spectroscopy can measure many different gases simultaneously, in situ and near-continuously, and can provide path-integrated amounts. Few studies, however, have investigated the accuracy of the retrievals of the main biomass burning gases (CC>2, CO and CH4), particularly across the broad range of concentrations found in ambient air to biomass burning plumes. Laboratory gas cell experiments were first used to evaluate the accuracy of the FTIR spectrometer and spectral analysis methodology deployed to retrieving concentrations of these gases at open biomass burning sites. The findings suggest that with optimisation of the retrieval parameters, column amounts accurate to within 5% can be confidently derived. During 2009-2011, the FTIR equipment was deployed to a number of experimental fires for the purpose of improving our understanding of emission factors. Three case studies are presented in this thesis: 1. Determining the seasonality of biomass burning emissions in Australian savanna lands - Seasonal (early- and late-dry season) emission factors were measured and compared, revealing no evidence of seasonality of emissions, in contrast to some previous works. Instead, Modified Combustion Efficiency explains most of the variation (e.g. 95% for CH4) in emission factors 2. Building an emissions inventory for UK fuel types - Emission factors for heather (Calluna vulgaris) were measured here for the first time, enabling the first measurement-based estimates of total UK biomass burning emissions for the main carbonaceous gases and selected volatile organic compounds. Typical flaming combustion emission factors for CC>2, CO, CFLt and NH3 are around 1711, 66.2, 2.8 and 0.53 g kg"1 dry fuel combusted, respectively. 3. Determining emission ratios using solar occultation FTIR spectroscopy of lofted plumes from large wildfires in the Northern Territory, Australia, and comparison of total column trace gas amounts with simultaneous and collocated measurements of Aerosol Optical Depth (AOD). The emission ratio of NH3 to CO determined from solar measurements is shown to agree with that measured on the ground using OP-FTIR. A relationship is established between total column amounts of CO and AOD, confirming that satellite-derived measures of AOD could be used as a proxy for trace gas amounts. Further work includes an exploration of the use of field-deployed FTIR in the study of aerosols in biomass burning plumes.

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No description available.

The bacteria E. coli HB101, E. coli DH1 and P. fluorescens 10586r were lux marked with the multicopy plasmid pUCD607. P. putida F1, was chromosomally marked by the insertion of the mini-Tn5 transposon. Growth and bioluminescence of E. coli HB101, E. coli DH1 and P. fluorescens 10586r were characterised and optimised for freeze-dried cultures (E. coli HB101 and E. coli DH1). The toxicity of aqueous solutions of MTBE, benzene and naphthalene was investigated using the biosensors, E. coli HB101, E. coli DH1, P. fluorescens 10586r pUCD607, and luc-marked, S. cerevisiae. The biosensors responded to high environmental concentrations. The EC50 values were comparable for E. coli DH1 and P. fluorescens 10586r. The yeast was shown to be quite resistant to MTBE. There is a general use of solvents, such as DMSO, to solubilise or extract compounds with high octanol water partition coefficients. This has a distorted effect on their actual toxicity. This was shown by the development of QSARs using the toxicity response of E. coli HB101 and plotting this against hydrophobicity. Bioluminescent based biosensors are useful tools not just only to assess toxicity but also to allow quantification and prediction of the remediation potential of certain compounds which enables a more complete assessment of their impact. A catabolic biosensor, P. putida TVA8, was used to further investigate pollutant relations. Correlating E. coli DH1, P. putida F1 QSARs with a QSBR developed for P. putida TVA8 allowed a better understanding of enzymatic specificity and toxicity. To evaluate the fate of MTBE in the environment it is necessary to investigate how it interacts with other co-contaminants. The determination of interactions is crucial to assessing environmental damage. Using the biosensor response and a model it was possible to investigate the nature of interactions. For MTBE:benzene mixtures, there was no increase in combined toxicity to E. coli DH1 and P. fluorescens 10586r. E. coli HB101 response had a different pattern and for low concentrations of MTBE:benzene synergistic interactions were observed. For MTBE:naphthalene, overall, the effect was additive. The toxicity of petrol containing MTBE was assessed since this is the major source of introducing MTBE in the environment. MTBE did not change the toxicity of petrol to the receptor tested. To assess the toxicity of MTBE's degradation products, E. coli DH1 was used. Most of MTBE degradation products were less toxic than MTBE, although TBF and formaldehyde had lower EC50 values. MTBE's effect as a solvent on co-contaminant specific biosensors was evaluated. MTBE changed the cell permeability in P. fluorescens HK44. Nevertheless P. putida TVA8 an E. coli DH5a showed no induction.

A molecular-level understanding of the surface complexation reactions between ecotoxic heavy metals and mineral surfaces is essential for determining their environmental fate. Many studies have investigated the surface complexes of elements on different mineral surfaces, but few studies have performed surface complexation modelling to determine the specific equilibrium constants for these complexes. To the best of our knowledge, no study has applied appropriate equilibrium constant data from surface complexation modelling for determining the stability and bioaccessibility of ecotoxic elements at actual sites of concern. This is the goal of this study. Chapter 1 is a review of the scale of metal contamination in the UK, the sources and the common methods of environmental impact assessment. This Chapter describes how surface complexation models can provide the most accurate means of modelling metal partitioning onto environmentally relevant mineral surfaces. Chapters 2 and 3 are surface complexation modelling studies of Pb and Zn respectively, onto the highly reactive and environmentally ubiquitous Mn oxide mineral phase, birnessite (o-Mn02). Chapter 4 is a geochemical survey of the River Axe Valley in Somerset, England. This area has been identified as having a high risk of contamination from mining, but has not received the same depth of investigation compared to other areas in the UK. This Chapter provides background information on this area, and investigates the mineralogy of the mine site soils, the caves through which the surface waters drain and the River Axe floodplain. The surface complexation models derived in Chapters 2 and 3 are successfully applied to model the partitioning of Pb and Zn in this setting, and assist in understanding the possible risk from the mine-derived metal-bearing sediment. Chapter 5 is a summary of the information required for the successful application of surface complexation models for site investigations in general, and gives an appraisal of their uses in future studies.

The overall aim of this work is to extend the knowledge of Urban Diffuse Pollution (UDP) and to assess the effectiveness of available remediation solutions in a confined urban context, where disruption from retrofitting proprietary treatment systems and products (PTS) to existing infrastructure causes major difficulties. The research presented addresses the quantification and remediation of UDP across a study area of the River Douglas in Wigan in the North of England. This study has involved an extensive programme of water quality sampling which has allowed micro-level changes in pollutant concentration to be observed as a result of weather event based urban runoff and enabling diffuse pollutants to be quantified. Following this the study goes on to suggest solutions to remediate sources of UDP exploring the use of vortex separation as a tool to treat polluting surface water drains. It provides performance data on several available PTS some of which were installed in outfalls into the study area in the River Douglas. These systems were monitored and further water quality data has allowed the quantification of the effectiveness in pollutant removal of different PTS. The study identifies the significant contribution of urban areas to diffuse pollution of river water and shows that similar studies need to become widespread if the problem of UDP is to be effectively addressed. Based on the significant contribution to knowledge in terms of the new water quality data generated both in relation to river water quality and treatment products and systems, a series of practical recommendations are proposed in relation to the identification and remediation of urban diffuse pollution.