Polycyclic aromatic hydrocarbons (PAHs) play an important role in urban air quality due to the toxic and carcinogenic hazard they present. A class of pollutants receiving increasing interest from researchers are oxygenated (OPAH) and nitrated (NPAH) derivative compounds. There is a need for an improved understanding of the sources, concentrations, behaviour and fate of these pollutants as they can pose a similar public health risk as PAHs and can enter the environment both from primary combustion emissions and secondary formation from atmospheric reactions. This study investigates the airborne concentrations of PAH, OPAH and NPAH compounds in U.K. atmosphere at heavily trafficked and urban background sites. Sampling campaigns were conducted to assess the spatial and temporal trends, primary and/or secondary sources, gas-particle phase partitioning and atmospheric degradation of PAHs, NPAHs and OPAHs. Differences in atmospheric concentrations between trafficked sites and the urban background site indicate a variable influence of road traffic emissions between different PAH, OPAH and NPAH compounds. Seasonal, diurnal and temporal patterns as well as positive matrix factorisation (PMF) source apportionment provide evidence of the key influencing factors governing the concentrations of PAHs, OPAHs and NPAHs in the urban atmosphere, in addition to the strength of road traffic emissions.

The fate and transport of citrate and PVP silver nanoparticles (AgNPs) was determined using large scale mesocosm studies with synthetic water and seasonal variations of natural lake water. We were able to produce a simple diffusion-sedimentation mathematical model which modifies sedimentation and diffusion equations for particles moving through a column. We introduced AgNP parameters including size and starting concentration to predict concentration and infer transport mechanisms in a 1 meter tall column over time. Ionic strength had a direct impact upon the behaviour and transformations observed by the two different surface coated AgNPs. Water collected in summer contained high TOC concentrations with low ionic strength. We observed increased stability to the citrate AgNPs and PVP AgNPs remained as nanoparticles for the duration of the study in the surface water. Winter water had the lowest TOC concentrations with high ionic strength. Citrate AgNPs showed increased aggregation and dissolution, whereas the PVP AgNPs remained stable. At different times of the year the transformations of the NPs change and during the warmer months AgNPs persist in particulate forms for longer periods of time in the surface waters.

This study has four principal aims. The first was to classify chironomid assemblages in canals using pupal exuviae. The second was to understand the distribution of species, their ecology and function. The third was to find indicator taxa which were suitable to classify canals in terms of water and sediment chemistry. The fourth was to analyze potential boundaries between Water Framework Directive (WFD) classes and develop a method to calculate ecological quality ratios that will support the objectives of the WFD. Calibrated chironomid-based inference models were constructed and these were used successfully to predict water and sediment chemistry parameters. This study found that there was potential to apply this tool to the requirements of the WFD and define ecological potential of canals through comparison of observed to reference EQRs (Ecological Quality Ratio). This was despite the fact that the study was conducted within a small geographical area.

Groundwater (GW) -fed streams are a common feature of paraglacial floodplains and are regarded as ‘biodiversity hotspots’, due to their role as valuable aquatic habitats. The hydrological dynamics which support GW-fed streams remain poorly understood. There is a need to improve understanding given paraglacial environments are extremely sensitive to the impacts of climate change. To address this significant knowledge gap site specific research was conducted on GW-fed streams within Denali National Park & Preserve, Alaska, during 2013 and 2014. Hydrometric, hydrochemical, hydrogeomorphic, and geophysical techniques were utilised to improve understanding of the hydrological dynamics and hydrogeomorphic controls that influence GW-fed stream occurrence. Paleochannels across paraglacial floodplains were identified as important preferential flow pathways (PFPs); and a first-order control upon GW-fed streams. In addition hillslope-runoff was established as an important hydrological flux to GW-fed streams. Colluvial deposits (e.g. talus cones) were highlighted as valuable hydrological stores on valleys-sides that made a direct contribution to streamflow. This research has raised concerns about the long-term stability of GW-fed streams in paraglacial environments due to changes in hydrogeomorphic controls (PFPs). It has also raised more immediate concerns about the short- to medium-term implications of shifting hydrologic regimes (e.g. declining winter snowpack) for GW-fed streams.

The passive continental margins which surround the North Atlantic region have been subject to widespread post-Triassic exhumation, the timing, magnitude and causes of which are debated. Exhumation of up to 6km (but more generally ≤3km) has been shown to have affected the Western UK Continental Shelf. This region contains a series of intra-plate extensional basins which formed during Permian-Jurassic rifting. Using a combination of palaeothermal (apatite fission-track analysis and vitrinite reflectance data) seismic and compaction data, this study has revealed an exhumation history of far greater complexity than previously suspected across the Southwest UK, with regional kilometer-scale exhumation episodes beginning during the Upper Triassic-Lower Jurassic (215-195Ma), Lower Cretaceous (140-120Ma), early Paleogene (75-55Ma), Eocene-Oligocene (35-20Ma) and Neogene (20-10Ma). Upper Triassic-Lower Jurassic exhumation appears confined to the footwalls of major basin bounding faults, suggesting footwall uplift was the principal cause of this episode of exhumation. Lower Cretaceous exhumation corresponds with continental breakup SW of Britain, suggesting a causative link. Early Paleogene exhumation was coeval with the Laramide phase of Alpine orogeny suggesting a causative link and additionally, marked heterogeneities in the pattern of this exhumation have been identified, casting doubt on the previously invoked role of plume-related epeirogenesis. Eocene-Oligocene and Neogene exhumation coincides temporally with the Pyrenean and Late Alpine compressional episodes. Seismic data shows that early and late Cenozoic exhumation was probably caused by compressional deformation related to Alpine orogenesis and/or Atlantic ridge-push. These observations imply that events at plate margins have exerted the primary control upon intra-plate exhumation in the Southwest UK onshore and offshore basin system with local faults providing an important control on the distribution of this exhumation

The unique properties which make cerium dioxide (ceria) nanoparticles (NPs) so useful in e.g. catalytic applications, pose a real risk to environmental systems and species alike. Increasing our knowledge of ceria NP characteristics in a range of aquatic systems was a contributing theme of this thesis. Nano-ceria particle sizes (dH) were found to significantly change due to adjustments in media composition. The addition of Suwannee River fulvic acid to an aquatic media decreased dH up to 88%, significantly increased the negative charge measured from zeta potential (ζ) and increased Ce dissolution by 2%. The presence of test biota significantly increased dH up to 80%, further increased the ζ negative charge and increased Ce dissolution up to 63%, predicted as being due to the presence of exudates. Nanotoxicological investigations using P. subcapitata showed a convincing size-dependent toxicity to well-defined synthesized nanoceria particles. EC50 values of 5 nm to 35 nm ceria particles (0.013 mgL to 0.8 mgL respectively) showed between 600 and 10 fold increases in toxic response compared to commercial nano-ceria particles (EC50 8 mgL). EC50 of 5 nm and 35 nm ceria particles showed significant metabolic differences compared to controls indicating a cellular response of P. subcapitata as a function of nano-ceria size and dose. Although metabolomic extraction methods are sensitive to cell density and temperature changes, metabolomic analysis has huge potential in future environmental nanoecotoxicological applications using P. subcapitata. It was evident from this study that further work is still required to help develop methods of NP characterisations under environmental conditions with a necessity for a future NP modelling protocol.

Paired kitchen-living room dust samples from 30 UK houses were collected for the analysis of BFRs, including PBDEs, HBCDDs and PBEB, EH-TBB, BTBPE, BEH-TEBP, DBDPE. Ninety-six plastic kitchen utensils were collected, screened for Br concentration by X-ray fluorescence spectrometer, with 30 of these samples analysed for BFR concentrations. A simulated cooking experiment was conducted to evaluate BFR exposure. Temporal and geographical differences in concentrations of BFRs in indoor dust samples were investigated via comparing BFR concentrations in UK samples in 2006-07 and 2015 and comparing 116 indoor house dust samples collected between 2014-15 from 6 countries (Finland, Greece, Spain, Jordan, US and Mexico) respectively. Concentrations of BDE-209 in living room dust were significantly lower and those of DBDPE significantly higher (p < 0.05) compared to concentrations in 2006-07 in UK dust. All target BFRs were present at higher concentrations in living rooms than kitchens. Considerable BFR transfer from kitchen utensils to cooking oils was observed and estimated exposure via cooking was 60 ng/day. US dust showed the highest Penta-BDE concentrations, followed by Mexico. Jordanian dust samples contained the highest concentrations of Octa-BDE. US and Mexican samples were found to display a similar composition to that found in the FireMaster® 550 formulation (EH-TBB:BEH-TEBP=4:1).

Virtually all temperate insects overwinter in diapause, a pre-emptive response to adverse environmental conditions and for many species a pre-requisite of winter survival. Increased global temperatures have the potential to disrupt the induction and maintenance of diapause. In the first part of this thesis, a four year phenological study of the blow fly, \(Calliphora\) \(vicina\), identifies that diapause is already being delayed due to high temperatures experienced by larvae within the soil layer. Laboratory studies identified that non-diapause life stages are capable of heightening cold tolerance through a rapid cold hardening ability, and winter acclimated adults maintain locomotion at lower temperatures than summer acclimated adults. A previously unrecognised threat, however, is that higher adult temperatures have the transgenerational effect of reducing the cold tolerance of diapausing progeny. In the second part of this thesis, the relationship between diapause and cold hardiness was investigated. The amino acid, alanine, was up-regulated as part of the diapause programme. Non-diapause larvae developed on an alanine augmented-diet expressed cold tolerance phenotypes similar to those of their diapausing counterparts. This adds to a growing body of evidence to suggest that amino acids have a direct role in insect cold tolerance.

There is growing public awareness regarding the risk associated with poor indoor air quality (Ward, Underberg et al. 2009) and indoors like in the home and workplace (Bernstein, Alexis et al. 2008). The aim of the study is to measure the magnitude of concentration in indoor environments, and personal levels of some air pollutants such as volatile organic compounds, PM2 s, polycyclic aromatic hydrocarbons, oxy-PAHs and Black carbon. Estimate the mass of BC that might be in the breathing zone and the lung dose. To conduct the personal exposure and home and workplace measurements, 45 healthy, non-smoking adult volunteer subjects were recruited. Concentration of the compounds might vary across volunteer's activities, therefore the importance of having personal exposure data which might be more representative. To accurately assess the human exposure and the human risk associates with the air pollution. New or recently remodeled building were found to have high concentration of VOC, therefore, a decay time should be considered before to move into a new buildings. BC particle size concentrations need to be investigate deeply as few information is available. Moreover not information about BC deposited dose was found.

Processes controlling the transport of dissolved-phase organic solutes through clay aquitards have been investigated. The study was centred upon a former UK industrial facility at which dissolved-phase aromatic solutes contaminated, and in areas penetrated, a discrete clay bed underlying the site. The lacustrine clay stratum (1-2 m thick) at 6 m bgs located in a sand aquifer was cored in 13 locations and intensively sampled with depth (primarily benzene, ethylbenzene, toluene and styrene). Two types of hydrocarbon invasion profiles were identified; (i) diffusion-based invasion and (ii) advection-dominated invasion. The latter has been shown from extensive physicochemical analysis of the clay cores in the laboratory to be primarily through connected “palaeo-root” holes. Root connectivity has been shown at various scales (serial sectioning, x-ray tomography). The hydraulic conductivity in the case of the advection-based profiles was ~0.04 m/d, whereas in the case of the diffusion-based profiles it was much lower at approximately 3 x 10-5 m/d. Sorption characteristics of the clay have been investigated yielding Kd over 2.98 – 6.95 l/kg and Kf over 2.27- 6.89 μgkg-1/ μgl-1 for PCE and Kd over 0.49 l/kg and Kf over 0.57 μgkg-1/ μgl-1 for benzene. Freundlich isotherms over 3-4 orders of magnitude concentration were found to be near-linear, a phenomenon likely attributed to the occurrence of modern organic matter within the sediments. A 2-D (Fractran) numerical model confirmed that where the clay deposits are homogeneous or contain partially penetrating root holes, slow diffusion dominated invasion will offer significant protection to the lower aquifer with breakthrough times through 1 m of clay of 40 years. Conversely, where the clays contain fully penetrating root holes, advection through the root holes causes much faster contaminant penetration. Matrix diffusion from preferential flowpaths causes contaminant to become distributed completely through the clay stratum. Discharge from the bottom of the clay stratum through root holes will be associated with a significant flux of dissolved-phase contaminant (where 30% of clay is rooted with 7.5 cm spaced root holes, ~0.25 mm aperture, contaminant flux is 0.134 g/m2/d) causing contamination of the lower aquifer. The accumulation of mass in the clay stratum is likely to cause prolonged contamination of the adjacent aquifers should the original source concentrations decrease. Indeed, evidence for such reverse diffusion at this site has been observed in one of the profiles. A 3-D code using high resolution data from x-ray tomography was developed to enable modelling of contaminant transport in finely characterised root holes.