http://bura.brunel.ac.uk/handle/2438/200 2013-05-23T20:22:49Z 2013-05-23T20:22:49Z Constantino, Carlos http://bura.brunel.ac.uk/handle/2438/7442 2013-05-23T10:17:32Z 2013-01-01T00:00:00Z

Title: The effect of sewage effluent on trace metal speciation: implications for the biotic ligand model approach Authors: Constantino, Carlos Abstract: This research examined the suitability of the biotic ligand model (BLM) approach for assessing environmental risk in surface waters consisting substantially of treated sewage effluent, and the implications of its use within a compliance-based regulatory framework aimed at controlling discharges of metals into the aquatic environment. The results from a series of Daphnia magna acute copper toxicity assays conducted in an undiluted sewage effluent medium demonstrated that BLMs could predict an acute copper toxicity endpoint with suitable accuracy. This finding contributes further support for the use of BLMs for assessing risk and compliance, even in effluent impacted waters. Additional studies, however, also demonstrated that effluent derived organic matter contained a greater concentration of metal complexing ligands per milligram of dissolved organic carbon than organic matter derived from natural sources. This indicates that effluent derived organic matter offers greater protection against the potentially adverse effects from metals than the protection offered by organic matter derived from natural sources. These studies also demonstrated that improvements in the accuracy of BLM forecasts were achievable by taking these differences into account which, from a regulatory perspective, is also desirable since this enhances the environmental relevance of compliance criteria. These findings therefore justify that consideration for the influence of site-specific metal complexation characteristics should included as part of the regulatory framework within which BLMs will be applied. The implication of the BLM approach for Severn Trent Water Limited is that, as currently proposed, the approach will require a reduction in the concentration of copper in the effluent discharges for a small number of wastewater treatment works (9), whereas for zinc, concentration reductions may be required for numerous treatment works (126). Description: This thesis was submitted for the degree of Doctor of Philosophy and was awarded by Brunel University

2013-01-01T00:00:00Z Crawley, Natalie Elizabeth http://bura.brunel.ac.uk/handle/2438/7362 2013-04-22T11:13:49Z 2013-01-01T00:00:00Z

Title: The global impact of climate change on fish Authors: Crawley, Natalie Elizabeth Abstract: Climate change is a global issue and the effects on fish populations remain largely unknown. It is thought that climate change could affect fish at all levels of biological organisation, from cellular, individual, population and community. This thesis has taken a holistic approach to examine the ways in which climate change could affect fish from both tropical, marine ecosystems (Great Barrier Reef, Australia) and temperate, freshwater ecosystems (non-tidal River Thames, Britain). Aerobic scope of coral reef fish tested on the Great Barrier Reef was significantly reduced by just a 2°C rise in water temperature (31, 32 and 33°C, compared to the current summer mean of 29°C) due to increased resting oxygen consumption and an inability to increase the maximal oxygen uptake. A 0.3 unit decline in pH, representative of ocean acidification, caused the same percentage loss in aerobic scope as did a 3°C warming. Interfamilial differences in ability to cope aerobically with warming waters will likely lead to changes in the community structure on coral reefs with damselfish replacing cardinalfish. Concerning Britain, there is evidence of gradual warming and increased rainfall in winter months over a 150 year period, suggesting that British fish are already experiencing climate change. It was evident from an analysis of a 15 year dataset on fish populations in the River Thames, that cyprinid species displayed a different pattern in biomass and density to all the non-cyprinid fish population, suggesting that there will be interfamilial differences in responses to climate change. Using a Biological Indicator Approach on the three-spined stickleback, Gasterosteus aculeatus, a 2°C rise in water temperature resulted in a stress response at the cellular and whole organism level. A 6°C rise in temperature resulted in a stress response at the biochemical level (higher cortisol and glucose concentrations), cellular level (higher neutrophil: lymphocyte ratio) and whole organism level (higher ventilation rate and lowered condition factor, hepatosomatic index and growth). G. aculeatus is considered to be temperature tolerant; therefore these results indicate that climate change may prove to be stressful for more temperature-sensitive species. This study has demonstrated that climate change will have direct effects on fish populations, whether they are in temperate regions such as Britain or in tropical coral reefs, but with strong interfamilial differences in those responses. Description: This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.

2013-01-01T00:00:00Z Pasley, Rehana Siddique http://bura.brunel.ac.uk/handle/2438/7272 2013-05-07T09:17:44Z 2003-01-01T00:00:00Z

Title: The physical and chemical reclamation and recycling of elements from black aluminium furnace residues Authors: Pasley, Rehana Siddique Abstract: Dross is the inevitable waste product generated by the world-wide primary and secondary aluminium industries. Around 3.5 million tonnes of white dross and 0.85 million tonnes of black dross are produced per year. Drosses are classified depending on metal content. White dross contains 40% and black dross contains 10% of aluminium. About half of the white dross is currently landfilled along with almost all of the black dross, and the annual cost to the UK industry of landfilling this waste is about £90 million per year. There is no commercially viable method of recovering the aluminium, which is potentially recyclable from these drosses, and no current conventional process has the custom-built capability to avoid their disposal to landfill. The practice of landfilling aluminium dross has raised problems for both industry and environment, because of potential leaching of heavy metals into groundwater from the landfill. The black dross has been physically and chemically characterised. The results show that the dross contains mostly metallic aluminium, aluminium nitride, alumina, sodium chloride, potassium chloride and silica with almost 50% of the dross being a mixture of sodium chloride and potassium chloride. A counter current leaching process has been developed to recycle the salts back to the secondary furnace. The environmental impact of black dross has been investigated using simulated landfill conditions. Leachability studies were carried out using water, and other leach media to model the following conditions: humic acid-containing systems, acid rain (pH 2.5), and acetic acid solutions (pH 5). Up to 60% of the dross was leached out in all media with the production of the saline solution providing the major impact. Only small amounts of aluminium were leached out under all these condition. No leachability behaviour was detected once the black dross was washed. So landfilling washed black dross can minimise both environmental and economical problems. Black dross residue, after washing with water, is enriched with alumina. Added value chemicals (of >95% purity) including aluminium hydroxide, alumina, aluminium chloride, aluminium nitrate, aluminium sulphate and aluminium carboxylates have been prepared using the washed black dross. Preliminary calculations have shown that the technology developed to recycle black dross to added-value chemicals is economically viable. A methodology has been developed which enables low grade alumnium waste, black dross, to be treated, commercially viable chemicals to be prepared, reagent use to be minimised through recycle and the diversion of millions of tonnes of furnace residue from landfill. Description: This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.

2003-01-01T00:00:00Z Westgarth-Smith, Angus http://bura.brunel.ac.uk/handle/2438/6594 2012-12-10T10:05:22Z 2012-01-01T00:00:00Z

Title: The North Atlantic Oscillation, climate change and the ecology of British insects Authors: Westgarth-Smith, Angus Abstract: Evidence is accumulating that climate change is having a significant effect on a wide range of organisms spanning the full range of biodiversity found on this planet. This study investigates the ecological role of climate change, the North Atlantic Oscillation (NAO) and habitat change on British insect populations. Despite the NAO having a considerable effect on British weather, the role of the NAO on British insects has not previously been studied in great detail. The World's two best entomological time series datasets were used – the United Kingdom Butterfly Monitoring Scheme (UKBMS) and the Rothamsted Insect Survey of aphids – both surveys with very large sample sizes and high quality data. Summary of main findings: 1. Warm weather associated with a positive NAO index caused the spring migration of the green spruce aphid (Elatobium abietinum), a pest species of spruce trees (Picea) to start earlier, continue for longer and contain more aphids. An upward trend in the NAO index during the period 1966-2006 is associated with an increasing population size of E. abietinum. 2. The NAO does not affect the overall UK butterfly population size. However, the abundance of bivoltine butterfly species, which have a longer flight season, were more likely to respond positively to the NAO compared to univoltine species, which show little or a negative response. 3. A positive winter NAO index was associated with warmer weather and earlier butterfly flight dates. For bivoltine (two generations in a year) species, the NAO affects the phenology of the first generation, and then the timing of the second generation is indirectly controlled by the timing of the first generation. The NAO influences the timing of the butterfly flight seasons more strongly than it influences population size. 4. Butterfly data from Monks Wood National Nature Reserve in Cambridgeshire showed that the NAO does not affect the abundance of the whole butterfly community, but it does affect the population size of some species. The NAO does not affect butterfly diversity, but there were decreases in butterfly diversity and number of species with time. 5. The total number of butterflies counted at Monks Wood was constant for most of the time series. However, the population size of the ringlet (Aphantopus hyperantus) increased from very low numbers to more than half the total number of butterflies counted each year. Therefore the total population size of all the other species has decreased considerably. 6. The NAO was more important than climate change in determining the flight phenology of the meadow brown butterfly (Maniola jurtina) at Monks Wood. In conclusion, the NAO affects the abundance of some species of British butterfly, and an aphid species, with a stronger effect on the timing of flight rather than abundance. There was evidence for a long-term decrease in the biodiversity of butterflies at Monks Wood and this decrease is likely to continue. Description: This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.

2012-01-01T00:00:00Z