With the current expansion of offshore oil activities in Arctic regions, there is an urgent need to establish the potential effects of oil-related compounds on Arctic organisms. The scallop Chlamys islandica is distributed throughout the sub-Arctic and has been proposed as a sentinel species for this region. In addition, the temperate scallop Pecten maximus occurs in regions of oil activity and, with increasing sea temperatures, the limit of its distribution may extend further into sub-Arctic regions. P. maximus also accumulates contaminants to a greater extent than the current temperate sentinel Mytilus edulis. A hierarchical approach, similar to that adopted to assess vertebrate immune function, was used to determine immunocompetence in the Arctic scallop C. islandica and the temperate scallop P. maximus following exposure to oil and oil-related compounds. The Arctic scallop C. islandica demonstrated a reduced immunocompetence following both dispersed and acute oil exposure. Immunomodulation in the scallops exposed to low levels of dispersed oil appeared to be reversible following removal of the contaminant stress (Chapter 3). However, a simulated oil spill resulted in mortalities and it remains unclear if the organisms are able to recover from the substantial immune suppression observed (Chapter 4). A component of crude oil and the most abundant PAH in aquatic ecosystems, phenanthrene suppressed immune function in P. maximus. These results indicated a link between PAH-induced oxidative stress and the subsequent inhibition in haemocyte immune function (Chapter 5). However, the ability of scallop haemocytes to recognise and respond to a pathogen-associated molecular pattern was not affected by phenanthrene exposure (Chapter 6). The immune parameters used in this research were shown to be sensitive, reliable markers of immunocompetence that can be directly linked to host resistance (Chapter 7). These immune parameters were also used to assess the sublethal effects of drilling wastes associated with offshore oil production (Chapter 8), indicating their potential as ecotoxicological monitoring tools.

Large pieces of plastic greater than a millimetre in diameter contaminate marine habitats worldwide and the associated environmental problems are well documented. In addition tiny fragments of plastic debris less than a millimetre in size have recently been reported. This thesis examines the distribution and environmental consequences of microscopic particles of plastic within marine habitats. To quantify the relative influence of wind and depositional environment on the accumulation of plastic debris, a mensurative experiment was conducted in a macrotidal Estuary. The overall trend was that material accumulated in down-wind sites. However, the relative importance of wind as a transport agent depended on the size and density of the plastic. Natural sediments are transported according to their size; but the extent to which models of sediment dynamics could be applied to the transport of plastic debris remains untested. I examined relationships between the abundance of microplastic debris and sediment particle size, latitude and human population density using samples from sandy shores worldwide. Microplastic was found at every location, showing the global extent of this contamination and there was a significant positive correlation between human population density and microplastic abundance. Sewage sludge disposal grounds were examined as potential sources of microplastic. Replicate sediment grab samples showed that disposal grounds near Plymouth and Newcastle (UK) had greater abundance of microplastic debris compared to reference sites. To investigate the biological consequences of ingesting clean microplastic particles the mussel, Mytilus edulis (L.) was used as a model organism. The fate of ingested plastic was tracked within the body tissues using a laboratory trial. Mussels were exposed to 3.0 and 9.61µm microplastic particles in seawater for 3 hours and then transferred to clean conditions. After 3 days ingested microplastic had accumulated in the circulatory fluid of M edulis. Smaller particles 3.0 µm were present in the haemolymph in consistently higher numbers than larger particles, and both sizes were still present after 48 days. There were no measurable changes in organismal health from ingestion of this material. However, it has been frequently suggested that plastics debris may transfer chemical contaminants to marine life. To test this, the sorption-affinity of candidate environmental hydrophobic contaminants from aqueous solution onto microscopic particles of polyvinylchloride and similar sized particles of sand was compared. Chemical analysis confirmed that polyvinylchloride absorbed more contaminants than sand. A second experiment examined the bioavailability of sorbed contaminants and chemical additives that are incorporated into plastic during manufacture. Laboratory trials using Arenicola marina (L.) showed that the sorbed contaminants and additives bioconcentrated in gut tissues leading to deleterious biological effects. In conclusion, microplastic debris is a ubiquitous form of contamination and when ingested, this material can translocate from the gut to the circulatory system and haemocytes, and can transfer chemicals into animal tissues, and reduce the health of animals near the base of the food chain. The implications of these findings are discussed in relation to potential measures to improve the management of plastics in society and to reduce the amount of plastic entering the environment.

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No description available.

In March 1997, the British government launched the United Kingdom National Air Quality Strategy. The Strategy sought to reduce levels of PM10 in the UK so that the objective of 50µg/m3 , measured as a daily maximum of running 24-hour means, was exceeded on no more than four days per year. Within three years this objective had been relaxed to allow for thirty five exceedences per year, albeit of a slightly lower level (because of changes in measurement technique), due to concerns that longrange transport of secondary particles would prevent local authorities from achieving this objective through local air quality management techniques. The study presented in this thesis seeks to contribute to the current body of work examining this issue. Two models, one at a regional/European scale, the other at an urban scale, have been used to estimate contributions to atmospheric PM10 levels from various sources. The results of the models, both independently and combined, have been used alongside relevant monitoring data to assess effect that local management techniques might have upon levels of PM10 in both urban and rural locations. The results suggest that, in many locations where the original air quality objective may not have been achieved, local emissions of primary combustion related sources may not have contributed more than 10-15% of total observed PM10 levels. This raises questions regarding exactly what the nature of the remaining portion of PM10 is comprised of, as current modelling techniques are unable to estimate this accurately: either due to an inability to represent the physics and chemistry, or due to lack of information about the sources. However, in the absence of a full understanding of either the composition or health effects of PM10, what factors should be considered in deciding whether or not local management strategies should be applied to the pollutant?

No description available.

In order to meet the UK Government's 60% greenhouse gas emissions reduction target, there is a need for non-experts to be meaningfully engaged with the issue of climate change. This thesis investigates the value of engaging non-experts with climate change at the individual level. Research demonstrates that individuals perceive climate change as temporally and spatially remote, and not of personal concern. There are psychological, social and institutional barriers to meaningful engagement with climate change. More effective methods for engaging the public with climate change are needed which address the psychological barriers to change. An 'iconic' approach was developed to harness the emotive and visual power of climate icons with a rigorous scientific analysis of climate impacts under a different climate future. 'I~ons' are defined as tangible entities which will be impacted by climate change, considered worthy of respect by the viewer, and to which the viewer can relate to and feel empathy· for. Such icons already exist: for example, melting of the West Antarctic Ice Sheet or Thermohaline Circulation shutdown. However, these 'expert-led' icons have failed to engage non-experts. The selection of nonexpert icons enables individuals to engage with climate change through their personal perceptions and values. A robust sourcing for 'non-expert icons' was carried out using focus groups and online survey methodologies. A suite of icons representative of the reasoning behind individuals' non-expert icons was selected. Expert-led icons were identified from 'Sleeping 9iants' emerging from the Exeter Avoiding Dangerous Climate Change conference. Impact assessments were then carried out for the suite of expert-led and non-expert icons under a specified greenhouse gas emissions scenario and to an imaginable timescale. Methodologies used to investigate climate impacts on the icons included a survey of expert opinion, quantitative modelling and spatial analysis using a Geographic Information System (GIS). The cognitive and affective impact of the non-expert and expert-led icons upon individuals was investigated through an evaluative pre/post test workshop. The expert-led icons· generally disengaged individuals. Expert-led icons had little personal impact and invoked emotions such as helplessness or boredom, and were considered too scientific or complex. Conversely, non-expert icons tended to impact upon the individual, the local area or nature; and invoked affective and cognitive engagement with climate change.

No description available.

An understanding of the ranges of toxicity of landfill emissions is crucial in determining the degree of concern we should have about the potential effects they could have upon nearby populations and the surrounding environment. Landfill leachates and airborne PM10 were collected and assessed for their transition metal-mediated in vitro bioreactivity by a plasmid DNA scission assay (PSA). Human tissue equivalents (EpiDerm -200 and EpiAirway -100 MatTek Corp., USA) were exposed to landfill leachate or PM10 and evaluated for cell viability (MTT assay) and trans-epithelial electrical resistance (TEER). The novel use of the oxidant-sensitive probe, DCFH, with landfill leachates was a good indication of leachate ROS activity. The results also revealed that leachate bioreactivity varied inter- and intra-landfills it was not possible to establish an easily elucidated trend associated with most commonly measured physical parameters (data kindly provided by landfill operators). Metal chelation by EDTA, DTPA, DES and Chelex resin caused significant attenuation of landfill leachate oxidant activity in both the PSA and DCFH assays. Acute leachate toxicity, gauged by a bacterial V. fischeri bioluminescence assay (ROTAS), revealed temporal-dependant hormetic responses from the bacteria which corresponded to high levels of TDS, conductivity and redox potential. Undiluted leachates were not acutely cytotoxic to EpiDerm -200 following 24h exposure. PM10 was collected from a Cardiff landfill and characterised by FESEM-EDX, ICP-MS and IC. The landfill PM10 physicochemistry varied year-on-year, and was dependent upon anthropogenic site activity. Metal chelation by EDTA, DTPA, DES and surrogate epithelial lining fluid caused significant attenuation of landfill PM10 oxidant activity in the PSA this was comparable to Cardiff urban PM10 reactivity. The PM2 5-01 soluble fraction was the most oxidant component. Landfill PM10 (500ug/ml) was not cytotoxic to EpiAirway -100 following 24h exposure. Preliminary toxicogenomics suggested several chaperones and heat shock proteins were up-regulated by landfill PM10. However, human disease causality was not confirmed.

Increases in global industrialisation are causing a growing release of pollution into the environment. Pollution, particularly by heavy metals is a significant problem as they are non-biodegradable, thus able to accumulate in ecological systems. The heavy metal copper (Cu) though toxic in excess is also an essential trace element that serves as a cofactor in many critical biological processes such as respiration, iron transport and oxidative stress protection. It is therefore important to assess the effects of Cu toxicity on the ecosystem and its natural communities, as environmental pollution impacts on an organism's genomic utilisation resulting in consequences for its biology and thus ultimately affecting population dynamics. Therefore the overall objective of this project was to investigate Cu homeostasis and toxicity using the soil dwelling nematode, <italic>Caenorhabitis elegans</italic> as a model organism. The effects of Cu toxicity on the population dynamics of <italic>C. elegans</italic> was determined by investigating changes in life cycle traits. The whole organism response to Cu toxicity was investigated in <italic>C. elegans</italic> and the EC50 and LC50 of CUSO4 was determined, along with the effects of Cu on growth and development. Cu tolerant mutants were created and phenotypic effects examined among them in order to assess adaptive responses to heavy metal exposure. To enhance our understanding of the complexities of Cu homeostasis at the genetic level the expression profile and functional significance of two putative Cu transporters Ctr and CutC were analysed. Using QPCR technology both genes were found to be down regulated with increasing CuSCU concentrations. RNA-mediated interference (RNAi) technology was exploited to create knockdowns of Ctr and CutC which resulted in significant differences in the <italic>C. elegans</italic> life cycle in the presence and absence of Cu. Overall RNAi of Ctr and CutC resulted in different demographic and phenotypic effects in <italic>C. elegans</italic>, indicating at their different roles in Cu metabolism, with Ctr postulated to be a high affinity Cu importer and CutC possibly with a complex role in regulation of Cu proteins. In Summary Cu homeostatis is a complex process maintained by the interactions of many interconnected, but also independent components to ensure that concentrations of this essential yet toxic element are tightly controlled.