Polycyclic aromatic hydrocarbons are ubiquitous pollutants and of these, benzo[a]pyrene (B[a]P) is the most widely characterised. B[a]P exerts its effects by the covalent binding of its metabolites to DNA. It has been well documented that the developmental stages of young organisms are highly susceptible to the effects of such pollutants. Presented here is a study on the effect or developmental stage in <I>Xenopus laevis</I> on the metabolism and subsequent adduct induction and repair. DNA adducts were measured by <SUP>32</SUP>P - postlabelling. Larvae were exposed at various stages of development, to waterborne B[a]P for 24 hours and allowed to recover for up to 6 days. A dose response of total adducts was seen at all stages studied. An increase in different adduct types was also observed with increasing liver development. Repair was biphasic, with adducts persisting for at least 6 days post exposure. Adducts were identified by the use of isomeric standards. The <I>trans</I> (+) <I>anti</I> B[a]PDE-N<SUP>2</SUP>-guanine adduct was detected in all stages and this adduct was shown to be non-repairable at stage 50. Larvae at stage 38 were shown to be the most sensitive to the effects of B[a]P, exhibiting signs of cyclopia and teratogenic effects to the forearms, up to 5 days post exposure. Young <I>Xenopus laevis</I> frogs exposed to B[a]P for 24 hours, were analysed for adducts in the liver, heart, pancreas, lungs, kidneys, brain, testes and ovaries. Adducts were detected in all organs except testes and ovaries, the greatest damage being observed in the liver and lungs. Adduct levels in the brain were close to the limit of detection. B[a]P-DNA adducts were examined in <I>Scophthalmus maximus</I> (turbot) a benthic marine organism, as a comparative species to <I>Xenopus</I>. Adduct profiles were different to those observed in <I>Xenopus</I>.

No description available.

Metal pollution within coastal and estuarine environments is of concern due to its potential to decrease economic value to society, impact marine ecology, and reduce recreational use. Biomonitoring provides a valuable tool to monitor metal pollution as it allows the measurement of bioavailable metals, which have the highest potential to impact ecology and human health. Metallothionein (MT) is a biomarker of metal contamination; it is induced by metal exposure, binding and detoxifying metals within cells. MT has been included in numerous studies monitoring metal contamination using marine invertebrates. Causes of natural variation on MT concentrations such as reproduction, tissue mass, salinity, and temperature, are known issues in common bioindicator groups such as mussels and oysters. This can disrupt the relationship between MT and metal concentrations within marine invertebrates and cause MT to be a less reliable biomarker. Seasonal effects to MT concentrations are not definite in the Manila clam (Ruditapes philippinarum), an invasive clam species within the UK, which could be a promising bioindicator due to its increasingly global extent. Bioindicator species such as brown seaweeds (e.g. Fucus spiralis) have not been studied as a MT biomarker species despite their extensive use as a general metal bioindicator. Furthermore, standard protocols for the treatment of organisms before MT analysis have not been defined and studies are inconsistent. This may be causing further discrepancies between MT and metal concentrations due to changes in concentrations that may occur between sampling and MT analysis, perhaps due to stress endured during transportation or protein degradation during storage. Therefore, an aim of this PhD was to evaluate the potential of, and limits to, the use of MT in selected marine organisms. A further aim was to the refine the use of MT, in terms of both methodological protocols and seasonal sampling strategies, to increase its reliability as a biomarker. It was found that the most appropriate treatment of organisms before MT analysis is to transport samples on ice from the field to the laboratory, and dissect as soon as possible thereafter. Depuration of organisms is not recommended before MT analysis, and storage at -20°C is acceptable for up to 10 weeks rather than the much lower temperatures used in some studies. It was found that gametogenesis in clam species in Poole Harbour during spring causes MT to be induced independently of metal exposure, compromising the reliability of MT. This suggests that the sampling of organisms should be restricted to a period of resting reproductive status. The potential of spiral wrack (Fucus spiralis) as a sensitive MT biomarker species was found to be limited, but may show promise in heavily contaminated environments, and warrants further research. Each of these findings can be implemented into international monitoring programmes as protocol in order to refine the use of MT. This thesis recommends that the shortcomings of current monitoring programmes are amended to include: evidence-based standard protocols for the pre-treatment of organisms; advisory restriction of sampling during gameteogenic periods; and the use of a range species as MT biomarker species.

Since the earliest work on controlled composting in the middle of the last century, the effectiveness of sanitisation has been determined using pathogen indicator organisms, such as E. coli and conventional enumeration techniques. Recent developments in molecular biology suggested the possibilities of replacing these 'standard' techniques with some form of PCR (polymerase chain reaction). The main part of the study related to the use of PCR to enumerate pathogen indicators in composted organic waste and compared it with conventional cultivation techniques recommended in the compost guidelines (PAS 100). The inactivation of pathogen indicators focus sed on the viability of their DNA and the survival of pathogen indicators in composted material. Membrane filtration was the standard conventional technique used to compare with molecular techniques. The main microorganism used in the study was Salmonella spp. Whilst PCR produced qualitative results' for detecting pathogen indicators, a quantitative approach was 'developed using cPCR (competitive polymerase chain reaction). The deletion method of pathogen-specific competitor fragments production for use in cPCR proved to be effective and was used to develop a competitor fragment. In this study, the cPCR technique was utilised to enumerate Salmonella spp. in aqueous samples. Results indicated that primers that produce a 670bp fragment from the E. coli gad AB gene did not represent the constructive choice for the cPCR method, because it resulted in PCR amplification products with faint bands and non-specific amplification. On the other hand, the primers that produced a 284 bp fragment from the invA gene were shown to be effective for the detection of Salmonella spp. by PCR owing to its high specificity. The clear and single band imaged in 2% agarose gel electrophoresis produced a good match; thus, it was highly significant in the cPCR and PMA-cPCR methods developed. The PMA (propidium monoazide) pretreatment step as DNA-intercalating dye was used in the cPCR protocol to provide viable/dead cell differentiation known as PMA-cPCR. The PMA-cPCR method developed was shown to be effective in enumerating the live Salmonella spp. DNA. The standard cultivation method gave approximately 1-2 log10 cfu/ml less compared to the PMA-cPCR results. These results indicated the existence of the VBNC (viable but non-culturable) state, whereas the viable cells failed to be cultured by the standard cultivation methods. Moreover, it also represented the non-loss of Salmonella spp. DNA during cross-linked upon bright light exposure. The results were approximately of the same magnitude order at average 108 cfu/ml for before and after the photo-activation procedure. The quantification results from the PMA-cPCR method for viable and non-viable DNA were analysed and compared with conventional methods and cPCR. This type of cPCR and PMA-cPCR methodology for quantifying Salmonella spp. shows very positive results, especially when utilised with an aqueous sample. Having developed the PCR based techniques for enumeration of Salmonella spp. work was then carried out in laboratory composters to study the survival of Salmonella spp. However, the DNA-based quantification for compost material was deemed to be an inappropriate method for use with quality monitoring of composting, as it always shows non- specific and non-amplification results. A few drawbacks concerning the use of PCR and PMA-cPCR in compost material were discussed, which led to various suggestions for future research. During the study, it became apparent that several different factors were responsible for the inactivation of Salmonella spp. as well as exposing the organisms to elevated temperatures. Different samples preparations was utilised to differentiate the biological, physical and chemical effects in composted samples. These results confirmed the effects of inactivation mechanisms involved, such as; antagonism and competition from other organisms, effect of chemicals changes and transportation. The PCR is a useful molecular technique for studying pathogen indicator detection and DNA-based quantification in solid waste. When being used it is recommended that highly competent individuals are needed if the nucleic acids amplification protocol is to be used for routine quality monitoring in the composting field. It is recommended that, despite false-positive results that depending on the elements contained in the compost materials, the standard enumeration techniques are the most appropriate for use in composting.

Water is one of our most vital natural resources for life sustaining and human's economic development and social well-being. Agricultural diffuse water pollution (ADWP), the biggest remaining problem of water pollution in the world, has been realised as a major threat for water quality and the implementation of the EU Water Framework Directive (WFD). Indicative estimates of the costs of water pollution from ADWP are about &pound;225 M per year in the UK, whilst failure to meet the requirements of the EU WFD by 2015 may incur heavy fines. From the technical and scientific points of view, there are three major gaps, namely, "method and tool", "research scale" and "fundamental knowledge" gaps between current ADWP research and the successful implementation of the EU WFD. It is timely to develop integrated catchment-scale numerical modelling tools or methods to handle the ADWP problem at the catchment scale. This thesis describes the development of an integrated catchment-scale modelling approach, ICEMAN, for supporting the effective decision-making of the ADWP sustainable management at the catchment scale, thus helping the implementation of the EU WFD in handling ADWP. In order to quantitatively describe the nutrient process in the complete hydrological cycle, it is necessary to integrate numerical water models into ICEMAN to calculate or simulate the groundwater pollution pathway vulnerability, groundwater pollution risk, water balance in soil, nutrients biochemical cycling in soil, and surface water quality and quantity processes. This study showed that GIS and the Arc Hydro model consisting of the modules of data mining, hydrological analysis, and visualisation can facilitate the developing and applying the ICEMAN by providing data support and powerful functions of spatial analysis. The DRASTIC model was applied in the case study area - Upper Bann Catchment, Northern Ireland for assessing the groundwater pollution pathway vulnerability of general pollutants and pesticide. The results showed that DRASTIC is suitable to be introduced into the ICEMAN for catchment-scale groundwater pollution vulnerability assessment. However, DRASTIC has drawbacks in the groundwater pollution risk assessment, namely, having no risk concept and considering no pollutant dynamic nature with runoff. A D-DRASTIC approach was developed in this study for reliable groundwater pollution risk assessment from diffuse agricultural sources based on DRASTIC within an ArcGIS environment. D-DRASTIC overcomes the pitfalls of applying DRASTIC in groundwater risk assessment. The results of applying D-DRASTIC in the case study showed that D-DRASTIC is helpful in guiding the activities of groundwater pollution prevention at the catchment scale and can be used in the development of ICEMAN. A numerical catchment-scale surface water model capable of the simulation of ADWP is necessary in developing the ICEMAN method. A HSPF model was selected based on the review of popular surface water models and tested in the study area. The calibrated and validated HSPF model can well represent the characteristics of surface water quantity and quality in the study area. Climate change scenario evaluation results in five years showed that when the annual mean temperature increase 3 Celsius the mean yearly total runoff volume will decrease by 11% and the mean daily river flow of five years will decrease by 11%. The results showed that HSPF is a suitable model in simulating the diffuse source surface water pollution and can be integrated into the ICEMAN. ICEMAN was developed by integrating the models of Arc Hydro, DRASTIC, D-DRASTIC, HSPF into an ArcGIS environment. ICEMAN can describe the nutrient biochemical cycles in soil, whole hydrological quantity and quality processes, and groundwater pollution vulnerability and risk, by considering factors in the catchment ADWP process, namely, meteorology, nutrient loading from different land uses, nutrient biochemical cycling in soil, nutrient dynamic nature with runoff and interflow, topography, depth to water, net recharge, aquifer media, soil media, impact of the vadose zone media, hydraulic conductivity of the aquifer, and the relationships between soil water and groundwater. The results of applying ICEMAN in the study area showed that ICEMAN can well support the decision-making of the catchment ADWP sustainable management. In the study area, ICEMAN provides satisfied simulation of river flow and quality, groundwater pollution vulnerability and risk zones, and quantitative descriptions of ADWP process including nutrient biochemical cycle in soil and can help better understand the ADWP characteristics in a specific catchment. In addition, ICEMAN can evaluate the impacts of water management plans on water processes under the climate change. For example, when changing 20% farming land into forest land in the Gamble's Bridge watershed of the study area, the mean concentrations of nitrate, nitrite, NH4, and P04 in river will decrease by 19%, 33%, 31%, and 31% respectively. ICEMAN, transferable to other areas, can bridge gaps of "method and tool" and "research scale" in the implementation the EU WFD in handling ADWP and can act as an important complement of the River Basin Management Plans. This multi-disciplinary study may provide a good starting point for tackling ADWP at the catchment scale in an integrated, quantitative, and sustainable manner. Therefore, the results in this multi-disciplinary study are not only useful for better implementation of the EU WFD, but also helpful for tackling the ADWP problem outside the EU.

This research set on a former reclaimed opencast coal spoil in Varteg Hills, South Wales, UK explores the phytoremediation potential of Alnus glutinosa (Alder), Betula pendula (Roth) (Birch) and Larix decidua (Larch), which are commonly used in UK land reclamation, to sequester metals: Zn, Cd, Mn, Pb and Cu, from mine spoils. This study also compares the abilities of newly planted trees to sequester metals on a new experimental site, within the landscape and compares these with those from older plantations on adjoining land. This chronosequence is used to evaluate the overall impact of forestation on metals levels in soils over two decades. Metal concentrations in soil were measured over three years and those in tree leaves were measured over two years. The majority of the samples examined lie between the UK defined thresholds for contamination but below levels that trigger immediate action and treatment. Samples within this range are placed within a new 'critical soil' category. Mapping the spatial distribution of contaminants across selected test plots shows the presence of micro-scale contamination hotspots on these sites. These show that while such sites may, on average, have sub-critcial levels for metal contamination, they may still contain sections where contaminants reach very severe levels. Planting trees in mixes is beneficial because different trees selectively remove different metal contaminants while some species benefit the soil in other ways. For example, while Alder leaves showed average concentrations of Cd, Zn and Mn, their roots also aid nitrogen fixation. Of the five metals selected for this study, two are known to be highly mobile (CD, Zn), two iii relatively immobile (Pb, Cu) and one is intermediate (Mn). Foliar analysis of Birch shows consistency in accumulation of Cd and Zn in leaves, while young Larch needles accumulated the highest concentrations of Mn and Pb. Correlation between movement of metals in soil and leaves over time, discovered that the uptake of Mn in Alder and Birch foliar on all plots and Larch on the new experimental plot is positively correlated to the presence of Zn in the soil. Studies of the general effects of forestation on metal concentrations in soil showed that metal levels declined significantly even on the most recently planted test sites. On four year old plots a 14-18% decrease in Mn concentrations and about 8% decrease in Cd and Zn concentrations were observed. Observations of the soils on the full 18 year chronosequence found that metal levels declined very significantly (p= 0.003 to 0.0002) through time. Based on the reduction of metal concentration in soil and uptake in leaves, it is possible to project 40 - 45 years for concentration of Mn to reach normal soil levels and about 20 - 25 years for Cd level to reach normal soil levels, provided the soil is not further disrupted by physical, chemical or biological activities which may recontaminate the spoil. This demonstrates, conclusively, that forestation is an effective means of metal remediation on the moderately contaminated lands produced by opencast coal-mining in Wales. Keywords: Opencast coal mining; Phytoremediation; contaminated land; Heavy metal uptake; Alder; Birch.

This thesis considers how pollution affects economic activities. Chapters 2 considers effects of pollution on humans' health. In an overlapping generation model with capital accumulation, agents' status is negatively affected by pollution. Individuals may invest in private health to reduce the burden of the environmental degradation, but this reduces the aggregate savings. Lower savings reduce the capital accumulation dynamic, reducing the optimal growth of the economy. The government can intervene to improve agents' health with public health spending, which crowds out private health investment and is complementary to savings. This work shows that, according to the initial level of capital of the economy and to the “net dirtiness", i.e. the difference of the pollution elasticity with respect to output minus the public health spending elasticity, the economy experiences different longrun growth equilibriums. Chapter 3 evaluates and compare the capacity of an emission tax and of free issued (non-auctioned) permits in terms of the incentives in investing in emission abatement research and in the social welfare. In the model, firms compete a la Cournot with knowledge spillovers. There are two different timing of the game: one where the government can credibly commit to the level of environmental policy; and the second timing where the government cannot credibly commit, and adjust optimally the policy after the firms innovate. This work shows that firms invest more in research when the government can credibly commit to the chosen level of policy. Chapter 4 investigates the role of pollution as a source of income inequality. Blackburn and Chivers (2015), in an overlapping generation model without credit market imperfections but in presence of loss aversion and uncertain return of investment, model agents that inherited from their parent and leave as a bequest to their offspring a positive amount of human capital. If the human capital is below a certain threshold, the loss aversion strongly influence agents, thus avoiding the investment. This reduces their possibility of realising profits and agents may end up in a low-income growth equilibrium with persistent income inequality. We extend their model introducing the pollution flow, which reduces the productivity of human capital and an abatement policy, which mitigates the negative effect of pollution. This work shows that in the presence of pollution, income inequality may increase and that the government can mitigate it through pollution abatement.

This thesis focuses on the simulation of the impact of trees on vehicular emissions in the urban environment, using CFD (Computational Fluid Dynamics) simulations of air-pollutant concentrations performed under the OpenFOAM software platform (k-ϵ model). Special attention was paid to the evaluation of the CFD model, by assessing the model results against wind tunnel and tracer experiments, as well as against a road side monitoring station. An overall accuracy of 30 to 40% on simulated concentrations was found, which is comparable to the results of previous studies. Most of the statistical parameters were also found to lie within an acceptable range. CFD models in the literature typically use idealised buildings to model wind flow and pollution dispersion. However, the methodology used in this thesis uses actual LIDAR data of buildings and trees to reconstruct a 3D representation of the different modelled scenes, such as Leicester City centre (2 x 2 km area). The modelled areas were on a scale larger than those usually used in other CFD studies. Furthermore, a special focus of this thesis details the interaction between trees and wind flow dynamics. In addition to the study of the aerodynamic effects of trees, the reduction of air pollution by deposition was investigated, which is something that has not yet been modelled at this scale. A final focus of this thesis was the ranking of current and prospective NO2 mitigation strategies including trees, building facades coated with photocatalytic paint and solid barriers. Trees were shown to be the most beneficial strategy when combining both economic and environmental effectiveness. With an attractive cost compared to other solutions, tree-planting policies could offer benefits to urban planning when funding is limited.

The presence and multiplication of Pseudomonas aeruginosa within some areas of the potable water supply of London was demonstrated by the analysis of the data collected from a thirteen month, bacteriological survey of the distribution system of the Metropolitan Water Division, Thames Water Authority. Construction materials designed for use within plumbing and distribution systems were shown to be capable of supporting the growth of Ps. aeruginosa in laboratory studies using tap water and one material, in particular was found to be responsible for the persistence of Ps. aeruginosa in new mains. The survival and growth of Ps. aeruginosa in tap water in the absence of construction materials was limited and it was clear that Ps. aeruginosa was not a normal component of the bacterial flora of treated water. The isolation of Ps. aeruginosa from potable water was not considered to be indicative of faecal pollution because it was unrelated to the presence of traditional faecal indicator bacteria - Escherichia coli and coliform bacteria. The multiplication of Ps. aeruginosa within the distribution system was another limiting factor in the use of this organism as an indicator of faecal pollution. It was proposed that Ps. aeruginosa would be suitable as an indicator of the presence in distribution and plumbing systems of construction materials that are unsuitable for use in contact with potable water by virtue of their ability to bring about a noticeable deterioration in the bacteriological, chemical or physical quality of treated water. The spread of Ps. aeruginosa by water has encouraged its appearance as a significant pathogen of man, animals and plants and a notable spoilage organism in industrial premises and commercial products. A clinical study of the potential health hazards associated with the presence of Ps. aeruginosa in potable water and water used for industrial processes was strongly recommended.

Environmental pollution by petroleum hydrocarbons has serious environmental consequences on critical natural resources upon which all living things (including mankind) largely depend. Microbial fuel cells (MFCs) could be employed in the treatment of these environmental pollutants with concomitant bioelectricity generation. Therefore, the overarching objective of this study was to develop an MFC system for the effective and efficient treatment of petroleum hydrocarbons in both liquid and particulate systems. Biodegradation of target hydrocarbons, phenanthrene and benzene, was investigated in dual-chambered microbial fuel cells (MFCs) using different inoculum types - Shewanella oneidensis MR1 14063, Pseudomonas aeruginosa NCTC 10662, mixed cultures and their combinations thereof. All the inocula showed high potentials for phenanthrene and benzene degradation in liquid systems with a minimum degradation efficiency of 97 % and 86 % respectively with concomitant power production (up to 1.25 mWm-2). The performance of MFCs fed with a mixture of phenanthrene and benzene under various operating conditions - temperature, substrate concentration, addition of surfactants and cathodic electron acceptor type – was investigated. The interaction effects of three selected operating parameters - external resistance, salinity and redox mediator were also investigated using response surface methodology. The outcomes of this study demonstrated the robustness of MFCs with good degradation performance (range 80 - 98 %) and maximum power production up to 10 mWm-2 obtained at different treatment conditions. Interactive effects existed among the chosen independent factors with external resistance having a significant impact on MFC performance, with maximum power output of 24 mWm-2 obtained at optimised conditions - external resistance (69.80 kΩ) , redox mediator (29.30μM, Riboflavin) and salinity (1.3 % w/v NaCl). The treatment of a mixture of phenanthrene and benzene using two different tubular MFCs designed for both in situ and ex situ applications in aqueous systems was investigated over long operational periods (up to 155 days). The outcomes of this work demonstrated stable MFC performance at harsh nutrient conditions and ambient temperatures. Simultaneous removal of petroleum hydrocarbons (> 90 %) and bromate, used as catholyte, (up to 79 %) with concomitant biogenic electricity generation (i.e. peak power density up to 6.75 mWm-2) were observed. The performance of a tubular MFC system in phenanthrene-contaminated soil was investigated in the last study. The outcomes of this work has demonstrated the simultaneous removal of phenanthrene (86%) and bromate (95%) coupled with concomitant bioelectricity generation (about 4.69 mWm-2) using MFC systems within a radius of influence (ROI) up to 8 cm. The overall outcomes of this study suggest the possible application of MFC technology in the effective treatment of petroleum hydrocarbons contaminated groundwater or industrial effluents and soil systems (mostly in subsurface environments), with concomitant energy recovery. MFC technology could potentially be utilised as an independent system in lieu of other bioremediation technologies (e.g. pump and treat, electrobioremediation or permeable reactive barriers) or integrated with existing infrastructure such as monitoring wells or piezometers.