Many environmental management tools have been developed aiming to reduce the impacts of dredging and protect the environment. As this has typically not been done in an integrated way that takes into account the socio-economic, environmental, technical and managerial aspects of dredging, there is a need to develop an integrated decision making tool to manage the impacts of dredging and help decision makers make sustainable decisions concerning dredging. The aim of this study was to develop a risk-based decision making framework for the integrated environmental management of dredging sediments in order to reduce the impacts of dredging and to lower the cost of environmental quality analysis and management. Selection of the best sediment management option using the risk-based approach of integrated environmental management has the potential to help effectively balance and prioritize the various socio-economic, environmental, technical and managerial aspects of dredging. The proposed framework will therefore utilize this concept throughout its six developmental steps. The first step reviews the literature on the impact of dredging and the two main factors that determine its magnitude, namely sediments and dredging technology. In order to manage the impacts of dredging efficiently, the relationship between scientific evidence and dredging activities will be assessed in the second developmental step. This step evaluates historical evidence from three dredging projects undertaken between 2006 and 2008 on the rivers of Sungai Sitiawan and Sungai Dinding, Perak, Malaysia. Monitoring and fish toxicological data from these projects are analyzed to determine their relationship with dredging activities performed in these rivers, with Geographic Information System (GIS) software used to illustrate the relationships found. The third developmental step assesses dredging problems other than the environmental impacts using Driving force-Pressure-State-Impact-Response (DPSIR) analysis, an IEM-based tool. This tool was employed in Malaysia’s dredging industry using interviews and a questionnaire-based survey. Dredging experts, including representatives from port operators, manufacturing companies and dredging contractors, were interviewed in 2008, with the socio-economy and management being found as the main drivers, together with environmental impacts, affecting dredging stakeholders in Malaysia. In 2010, further dredging experts (including marine ecologists, registered chemists, professional and chartered engineers, environmental consultants, university professors and environmental analysts) responded to the questionnaire, with results suggesting that governance of dredging in Malaysia is weak and that it is essential for Malaysia to review its current dredging environmental management tools and practices. The fourth developmental step develops the first stage (screening) of the proposed framework based on understanding provided by the three steps developed previously and demonstrated using Malaysia as a case study. This screening stage utilizes the historical dredging monitoring data and the contamination level in media data into Ecological Risk Assessment (ERA) phases, which have been adjusted for benefits in cost, time and simplicity. Using case studies from Malaysia, the fifth developmental step (Tier 1) shows how Multi-Criteria Decision Analysis (MCDA) can be used to analyze and prioritize dredging areas based on environmental, socio-economic and managerial criteria and is demonstrated for the Tier 1 stage. The results from MCDA will be integrated into Ecological Risk Assessment (ERA) to characterize the degree of contamination found in the areas. Priority areas, their degree of contamination and other concerns are then identified and brought forward to the sixth developmental step (Tier 2 stage). The Tier 2 stage is demonstrated using previous findings and analyzed using MCDA, in order to identify the best sediment management option, accounting for the economic, environmental and technical aspects of dredging.

Sea-level rise continues to be an issue of societal concern. It is a fact that millions of people live close to the coast and will be at risk both directly and indirectly from sea-level rise. Understanding the future begins in the past and so this thesis considers Holocene and modern sea-level variations in the Caribbean region, an area particularly at risk from long term sea-level rise. I construct a catalogue of 561 published Holocene sediment ages and depths, primarily fossil corals and mangrove peats. I derive probability distributions of the habitable ranges of corals and peat using modern growth and abundance records. These distributions are used to simulate realisations of sea-level position in the past. The relative sea-level (RSL) position and RSL rate are calculated at 500 year time slices to construct sub-regional sea-level histories. At each time slice, I select the realisations that fall within a 2000 year time window and calculate the least-squares estimate of RSL rate and RSL position. Results show Caribbean wide spatio-temporal RSL changes. From 7000 to 4000 cal yr BP, RSL rates were »2 mm yr−1 in the north (Cuba and Florida), »1 mm yr−1 in the east (Lesser Antilles and US Virgin Islands) and »2.5 mm yr−1 in the south west. From 4000 to 1000 cal yr BP, sea level rose between 3 (US Virgin Islands, Venezuela and Trinidad) and 5 metres (Florida, Belize). During the last 1000 years, RSL rates fell below 1 mm yr−1 and by 500 cal yr BP lay between 0 to 0.5 mm yr−1. The spatial variation between sub-regional RSL histories is also investigated by using a spherically symmetric, rotating numerical model that simulates sea-level change and vertical ground motion (VGM). I derive model RSL histories at the sub-regions in the Caribbean using a single deglaciation model and a range of earth parameters. By minimising the misfit of the model RSL curves to the data driven RSL curves, I find a representative model fit where lithospheric thickness is 71 km, upper and lower mantle viscosities are 0.5 and 10 × 1021 Pa s respectively. To find the change in sea-level rise in modern (1960 to 2012) times compared to the late Holocene, I calculate RSL and absolute sea-level (ASL) rates using 49 tide gauge records and satellite altimetry. I apply three corrections to remove seasonal and regionally coherent noise and calculate a least-squares estimate of sea-level change. Results show that present day RSL rise is up to three times greater than in the late Holocene, though there remains a small (· 1 mm yr−1) long term contribution from the last deglaciation. For individual sites, I found that variations in VGM can exacerbate long term sea-level change enhancing the risk of coastline communities.

Information may resolve uncertainty and uncertainty is pervasive. Thus, seeking, producing and trading of information are common economic activities. This is also true in the economics of the environment and for the different stakeholders therein involved. The central aim of this research is to investigate some theoretical aspects of the value and effects of information in environmental economics. Information is valuable either as a decision aid in contexts where either health and environmental characteristics of goods are uncertain or as the object of direct valuation under different provision rules. In a choice context three questions arise providing grounds for empirical investigations.

No description available.

Three research propositions were made in this study. These related to the knowledge gaps existing In either the theory or practice of environmental Impact assessment (EIA) and the ISO 14001 environmental management standard. The first one suggests that, in spite of the recognised significance of EIA follow-up, this EIA stage has often been ignored in practice. The second proposition argues that the current approach to EIA focuses on the minimisation of negative environmental impacts of a project rather than the enhancement of positive ones. The third proposition suggests that although ISO 14001 contains environmental planning requirements, they have shortcomings, which preclude ISO 14001 from playing the role of EIA in environmental planning of projects.

The discharges of radioactive materials from the Windscale Fuel Processing Plant have resulted in the build up of radionuclides in the accreting mud banks of adjacent estuaries. A mathematical model has been developed which can successfully predict the activity profile of each radionuclide in the sediment. Laboratory experiments have shown that the distribution coefficient for caesium depends on a number of variables such as sediment particle size, salinity, initial radionuclide concentration and time. The model described can be used to predict likely changes in the activity profiles in the sediment if the waste discharge rates are altered. Measurements of the effect of salinity on the adsorption of caesium onto sediment would indicate that a change in the salinity of the discharges might reduce the uptake of activity onto particulate matter in the immediate vicinity of the discharge pipe and consequently reduce the amount of activity building up in the mud banks. Three types of adsorption site on the sediment have been established with quite different characteristics. The construction of two types of alpha spectrometer is discussed. It is shown that the chemistry of an "extractive scintillation" method can be used to prepare samples for counting on a surface barrier detector. The feasibility of using a large area gridless pulse ionisation chamber for environmental alpha spectrometry is discussed and the spectrum of the instrument built showed to have a resolution of 64 KeV.

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No description available.

Elemental analyses have been made of dissolved, suspended particulate and sedimentary Cu, Mn, Zn following axial surveys of the Tamar Estuary. Continuous monitoring of the estuarine master variables was made during each survey. Selective digestion methods were applied to the particulate and sediment samples to determine the detrital and non-detrital fractions. These experiments showed that in general about 80-100% Mn, 60% Zn and 20% Cu were in the non-detrital form. Rank order correlation tests of the sediment results showed that the summer profiles were consistently different to 20 randomly generated profiles of the same data. In contrast the winter distribution showed a greater tendency to randomness which was related to the high energy resuspension processes dominant during that period. This temporal variation in sediment metal content has been interpreted in terms of a seasonal sediment accretion-erosion cycle observed in the estuary. The axial profiles of dissolved Zn and Mn often showed similar trends with a minimum concentration in the freshwater above the salt-wedge and a mid-estuarine maximum. A statistical analysis of the data using F-ratio tables, which also took into account variations in both salinity and'turbidity, showed that the relationship between Zn and Mn was in agreement with the hypothesis that the two elements are responsive to similar sorption processes in estuaries. Copper was rarely correlated with either Mn or Zn under the same reaction conditions, which suggested a different estuarine geochemistry. The dissolved, suspended particulate and sediment data for the three metals were then used to develop a two-box model of the Tamar Estuary. The seasonal transfer of Cu, Mn and Zn was then determined using the model. In general the overall mass transport followed the sequence Mn > Zn > Cu, with large transfers of material from the upper to lower estuary occurring in winter. The model was of use in predicting the fate of metals input from the mineralised catchment area feeding the Tamar Estuary.

No description available.