Investigating the behaviour, fate and transport of Silver nanoparticles (Ag-NPs) in wastewater treatment plants (WWTPs) is of great importance due to their presence in many consumer products and its potential to be toxic to environmental organisms. In this study, the transformation and fate of Ag-NPs was assessed using a multi-method characterisation approach, prior-to, during and post-aeration in the pilot sequencing batch reactor (SBR) and over a 21 day period in SBR. Synthesized 10 nm citrate and polyvinylpyrrolidone (PVP) coated Ag-NPs were spiked into OECD synthetic sewage (OECDss) media and it constituents and in the (OECDss) + activated sludge (AS) media. Ag-NPs show agglomeration, dissolution and changes in surface chemistry at all measured time points i.e., at 0 hrs, at 24 hrs, at 45 hrs (during aeration) and at 48 hrs (during settling) and indicated that 80% of the citrate and PVP Ag-NPs could be removed in the form of Ag2S, AgCl and Silver Phosphate-NPs. More than 50% of Ag-NPs accumulated within the sludge over a 21 day period (with no addition of fresh AS), and this occurred via physical adsorption on the surface of the AS flocs. This work demonstrates that Ag-NPs in wastewater can undergo a range of transformation processes, which include oxidation, dissolution, agglomeration, precipitation in an SBR pilot plant.

In this thesis atmospheric and oceanic conditions important for the development of wind storms on different time scales are analysed. The potential usefulness and limitations of seasonal prediction models and long-term reanalyses with respect to wind storm frequency is investigated and sources of potential seasonal predictability of wind storm frequency are discussed. On the synoptic scale tropospheric growth conditions such as baroclinicity, latent heat and upper level divergence show greater magnitudes of one standard deviation on average compared to all extra-tropical cyclones. Mid-latitude Rossby waves show generally greater amplitudes for different wave numbers during wind storm events. Greater amplitudes are also found in wave numbers not typically associated with storm track activity. The analysis of extra-tropical cyclones and wind storms on the seasonal scale reveal positive, significant skill for some European regions in state-of-the-art seasonal prediction models. North Atlantic sea surface temperatures (SST) are shown to be a source of seasonal predictability and a potential reason for the achieved skill for wind storm frequency predictions in reanalysis and AMIP-type sensitivity experiments. The role of tropical Pacific and Atlantic SST for the record number of wind storms over the UK in winter 2013/14 is discussed.

Climate change is subjecting many ecosystems to novel environmental conditions, including unprecedented extremes of drought that may push communities beyond critical ecological thresholds. Stream ecosystems may be particularly prone to catastrophic responses, due to a dependence on flowing water and continued exposure to other major threats to their ecological integrity. However, a lack of gradient-based approaches that explore beyond the limits of current disturbance regimes constrains our ability to predict the impacts of future droughts. This study used artificial channels (mesocosms) as perennial headwater stream analogues to simulate a broad gradient of drought intensity, ranging from flowing controls through fragmented pools to dewatered streambeds. Drought intensification pushed macroinvertebrate communities over structural and functional thresholds, and eroded complex food webs from the top down and the bottom up. Moreover, important exceptions to some established ‘rules’ in disturbance ecology emerged, with population collapses not biased to larger body sizes or higher trophic levels, and community responses not buffered by high functional redundancy. Benthic algae, macroinvertebrates and fish were all sensitive to relatively low intensity drought, suggesting that pool fragmentation, and not streambed drying, may be the most crucial stage of habitat loss for many running water ecosystems.

Exposure to particulate matter (PM) and its components is associated with negative health outcomes. It is hypothesised that the channel through which these effects are expressed is via the mechanism of inflammation and oxidative stress. In order to assess the relationship between exposure and health outcomes in different personal and indoor exposure environments (Homes, Office, Commuter mode, Restaurant, Shisha lounge, Busy traffic site and Control environments), the association between exposure to PM/PM components and changes in local/systemic inflammation and oxidative stress biomarkers (EBC-nitrate, EBC-nitrite, EBC-pH and urinary 8-oxodG), alterations in autonomic and lung functions respectively were measured. The acute/elevated exposures showed significant increases in EBC nitrate and nitrite immediately after exposure but EBC-pH and urinary 8-oxodG, did not significantly change in post exposure measurements. In some of the exposure scenario, significant correlations were observed between the pollutants measured and the biomarkers. Urinary metals were also analysed and compared with biomarkers and PM/PM components. Indoor PM mass-size distribution, showed that PM prevailed in the 250 – 500 nm and the 2500 – 5000 nm size range. Na, Fe, Mn, Ca and Mg prevailed in the coarse mode (2500 – 5000 nm) and toxic metals such as Mn, Cu, V, Ni, Pb and Sn were observed. Si, S, K and Fe were the most prevalent elements observed in the particles collected analysed with TEM/EDS. The increases observed in post exposure measurements, significant correlations observed between the biomarkers and the measured PM/PM bound components in the different environments and alterations in lung function, suggests that exposure to PM/PM bound components have the ability to cause inflammation/oxidative stress thereby affecting human health. This study shows that biomarker expression after exposure can be used to measure acute responses.

In this study a number of analytical techniques for the screening, quantification and identification of brominated flame retardants in consumers’ products, electric and electronic waste and indoor dust is explored. The presented work can be conceptually divided in two parts: - The first explores, evaluates and pushes the limits of solid sampling techniques (i.e. X-Ray Fluorescence and Laser Ablation Inductively Coupled Plasma Mass Spectrometry) as a tool for the total elemental quantification of Bromine and its use as a metric for BFR content in consumers’ goods and waste. The XRF method proved to be accurate to 94% (relative to LA-ICP-MS results), making the technique (used with the developed calibration) reliable for the quantification of Br in polymers. REEs concentrations obtained with LA-ICP-MS were used to evaluate the origin of contaminants in FCAs and toys. - The second part explores the suitability of solid sampling techniques (that do not require sample preparation) and simplified liquid sampling techniques (that require sample preparation in the form of solvent assisted extraction) for the compound specific, semi quantitative evaluation of BFRs in plastic material and indoor dust. DIP-HRMS and DART-HRAM showed sufficient linearity over the calibration range and mass determination accurate enough to unequivocally identify BDE209 in polymeric matrices. GC-ICP-MS analysis performed with ad-hoc developed hardware provided reliable data for the semi-quantitative evaluation of indoor dust PBDE profile.

Oil and gas development projects are major sources of social and environmental problems particularly in oil-rich developing countries like Nigeria. Yet, data paucity hinders our understanding and ability to quantify the direction and magnitude of events. This thesis contributes to the field by adopting an interdisciplinary approach to improve our understanding of the links between oil-related socio-environmental problems and pipeline operation in the Nigerian oil and gas industry.

River temperature is important for cold water adapted freshwater fish species, such as salmonids. Salmonids command a high economic, social, recreational and conservation value and are therefore frequently the focus of management. In recognition of the importance of river temperature, and against a backdrop of sparse data availability, the Co-ordinated Agenda for Marine, Environment and Rural Affairs Science (CAMERAS) prioritised the development of a strategically designed national river temperature monitoring network for Scotland to assess and predict the likely effects of climate change and inform mitigation strategies. The work undertaken for this thesis filled this research gap. Specifically, it delivered 1) a quality controlled national river temperature monitoring network (Scotland River Temperature Monitoring Network), 2) new and innovative statistical approaches for modelling river temperature, 3) improved understanding of the controls on large-scale variability in river temperature across Scotland, 4) characterised river temperature for Scotland, 5) identified rivers and regions that are likely to be most sensitive to climate change and 6) investigated the potential of riparian woodland to mitigate high river temperatures that are potentially damaging to Scotland's valuable freshwater fisheries. The outputs of this research have provided valuable management tools to river and fisheries managers and policy makers.

There are two distinct research foci within this thesis; the role of aerosol particle and trace gases on (i) visibility and (ii) tropospheric chemistry. This work investigates short and long term visibility, by exploring the combined influence of atmospheric aerosol and meteorology. Observations were fitted to a newly developed light extinction model to generate predictions of historic aerosol and gas scattering and absorbing properties, explaining long term visibility trends and their dependence on meteorological conditions. This model incorporates parameterizations of aerosol hygroscopicity, gas absorption and particle concentration, scattering, and absorption. Historical visibility data can therefore be used to assess trends in aerosol particle properties for time periods when observational data are scarce or non-existent. Short term visibility variations caused by particulate matter from firework and bonfire emissions is presented. It is shown that a reduction in the atmospheric visibility nationwide is -25%; which is a consequence of increased loading of atmospheric PM, and is found to be dependent upon relative humidity. Within tropospheric chemistry, HONO is an important source of OH radicals, and daytime HONO sources are poorly constrained. This work explores the abundance of HONO during a solar eclipse as a natural short-term perturbation to atmospheric photochemistry. A chemical kinetic model is employed to predict the concentrations of HONO using different source scenarios. The study provides insights into the variation of HONO with meteorology, traffic emission and other source.

The aim of the study is to investigate the variability in riverbed permeability fields in an unprecedented spatial resolution and quantify the impacts on controlling hyporheic exchange fluxes. Geophysical surveys were conducted deploying GPR on the floodplain and within the channel. At locations identified to be representative for the range of streambed hydrofacies in investigated stream reach, multi-level mini-piezometer networks were installed in the streambed. The results of GPR surveys in both sites provided different radar reflections which indicated a range of different radar facies and helped to delineate the type and extend of high and low conductive materials. The localised high Darcy fluxes inside high conductivity piezometers indicated rapid discharge of groundwater due to the enhanced connectivity to deeper groundwater. Whereas, low flow velocity within and around low conductivity peat and clay lenses indicated that these layers substantially inhibit groundwater upwelling, resulting in enhanced streambed residence and reaction times. The increase in residence time and the related depletion in the volume of DO facilitated the development of conditions necessary for nitrate reduction. In contrast, preferential flow paths and short residence times in highly conductive drift deposits resulted in no significant changes in nitrate concentrations along hyporheic flow paths.

Brominated flame retardants (BFRs) are ubiquitous in indoor air and dust, leading to human exposure and resultant concerns about adverse impact on health. Despite elevated concentrations in dust, little is known about how BFRs transfer to dust from treated products. A test chamber was constructed to investigate pathways via which the polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) migrate from source materials to indoor dust. These were: (1) BFRs volatilise and subsequently partition to dust, (2) particles or fibres of the source abrade, transfering to dust directly (3) direct source-dust contact results in transfer. A HBCD treated textile curtain, and a PBDE TV casing were both tested. Partitioning post volatilisation was a less effective mechanism than abrasion. Direct source-dust contact resulted in effective and rapid transfer. A forensic microscopy investigation on ‘real world’ dust of elevated BFR content identified polymer particles containing BDE-209, likely originating from a BFR treated polymeric material indicating abrasion. An \(in\) \(vitro\) extraction test investigated the bioaccessibility of dust contaminated \(via\) pathways (1) and (2). Results indicate bioaccessibility may be less efficient from samples containing elevated concentrations of BFRs, and from dusts contaminated primarily via abrasion. More detailed research is essential to confirm these findings.