Many contaminants exhibit decay. Decay mechanisms include consumption by bacteria or radioactive decay (temporal decay uniform across the flow), heat loss or evaporation through the surface (decay decreasing with depth), and break up by turbulence (decay proportional to the product of velocity and depth). This thesis investigates how the decay of pollutants in a river effects the dilution process and the selection of discharge siting to achieve minimum environmental impact. For a non-symmetric river with non-reversing flow, exact solutions are presented that illustrate the effect on the optimal position for a steady discharge of cross-channel variation in the decay (uniform, decreasing or increasing with depth). The optimal position is shifted to deeper or to shallower water accordingly as the temporal decay divided by flow speed decreases or increases with water depth. When advection dominates diffusion, there are special directions (rays) along which information is carried. For steady, unstratified, plane parallel flow, the effects of decay are allowed for in specifying these special directions. Two special cases are considered. Firstly, for a smoothly varying depth, a general result has been derived for the curvature of the rays as effected by spatial non-uniformity in decay, mixing, flow speed and flow direction. Secondly, for discontinuous variations in depth, diffusivity, velocity and decay, approximate concentration formulae are derived. Ray bending indicates that the downstream propagation of pollutant is principally in the low-decay region. Computational results are used to give pictorial illustration of the concentration distributions and of the difference between discharging at non-optimal and optimal sites.

The Revised Bathing Water Directive will have a major impact on the way that Competent Authorities assess water quality. It requires work in various disciplines to be streamlined into delivering the methods and approaches needed to deliver the requirements of the Directive. To achieve this, Competent Authorities will have to engage effectively with all stakeholders and embrace the principles of Integrated Coastal Zone Management. This does not currently happen. This research assessed the legislative and managerial development of the revised Bathing Water Directive proposal COM 581 and developed methods and approaches to support this, through the production of an interdisciplinary Bathing Water Management Framework (BWMF). This led to the creation of biological monitoring and communication methods that could deliver the requirements of the revised Directive. This research showed that the revised Bathing Water Directive will require Competent Authorities to work with others and look at novel ways of gathering and communicating information required for the Directive; including biomonitoring and emerging communication technologies. This will require the UK and Europe as a whole to embrace the principles of Integrated Coastal Zone Management (ICZM). This research has shown that interdisciplinary research can be successful in answering complex, cross-cutting issues such as how to develop a holistic overview of Bathing Waters. When compared to a monodisciplinary approach, this research has advanced in several disciplines and also created a brand new intellectual space in the form of the framework. Whilst the interdisciplinary outputs are powerful the research has also delivered the article requirements of the Directive.

The presence of dissolved organic carbon (DOC) in raw water can cause a number of issues iC potable water treatment due to its effect on aesthetic, chemical and biological water quality parameters. Of particular concern is the role of Doe as a precursor to potentially harmful disinfection by-products (DBPs), most notably haloacetic acids (HAAs) and trihalomethanes (THMs), which are formed during the chlorination of natural waters. Rising concentrations of Doe in surface waters draining upland catchments have been reported in the past few decades. This is a major concern for drinking water companies in these areas given the regulatory requirement to maintain THM concentrations below maximum permissible levels. Coagulation-flocculation is recognised as the most effective means of removing Doe from raw water during potable water treatment and controlling the formation of THMs in finished water. The present study is focussed on upland drinking water reservoir catchments in the North Wales area. In this area many catchments comprise extensive areas of forest and peatland coverage, both of which have been associated with high DOC loading of surface waters. In this study the concentration and character of leachable DOC was compared in soils derived from different habitats in order to assess the effect of habitat type (beech, spruce, larch and pine forests and blanket peat) on Doe treatability and THM formation potential (THMFP). Significant differences were identified between different habitats, with the beech habitat identified as most appropriate for drinking water catchments due to it having relatively low leachate DOC concentration, THMFP and colour.

No description available.

Over the last decade the development and use of nanomaterials (NMs) and nanoparticles (NPs) has increased at a great rate. As a result there is an ever increasing risk of exposing humans and wildlife to these potentially harmful materials. Titanium dioxide nanoparticles (TiO2 NPs) and carbon nanotubes (CNTs) are two of the most widely used NMs at present. Their potentially harmful effects on organisms and physicochemical properties have been investigated in a growing number of scientific studies. However understanding the level of risk they may pose is far from satisfactory. The present body of work has addressed various aspects of this field. In order to better quantify the fate of TiO2 NPs in the environment the methodology of measuring Ti from TiO2 NPs was improved using ICP-OES and single particle ICP-MS was demonstrated to provide the first steps towards characterising the nature of TiO2 NPs in liquid-phase media. The potential harm of TiO2 NPs and single walled carbon nanotubes (SWCNTs) to zebrafish was investigated in two separate studies. Little evidence of physiological toxicity was found and the only nano-scale effect of note was an increase in total glutathione of zebrafish exposed to TiO2 NPs. More subtle effects in reproductive studies were further investigated using the three-spined stickleback in a longer term investigation. Similarly to the zebrafish there was little evidence of any physiological disturbances and the well documented reproductive behaviour of the stickleback was not significantly altered as a result of TiO2 NP exposure. This body of work has added to the understanding of the potential toxic effects caused by exposure to both TiO2 NPs and SWCNTs. Improved methods for the detection and characterisation of TiO2 NPs have been demonstrated and the most sensitive tools for ecotoxicological assessments of NP toxicity have been elucidated.

Pharmaceuticals that are intended for human use are frequently detected in the aquatic environment. This is predominantly from the excretion of pharmaceuticals by patients, in their urine and faeces, which subsequently enter sewage treatment plants. Sewage treatment provides a final opportunity for pharmaceutical removal, prior to discharge into the environment, however, removal is often incomplete. Once in the environment, pharmaceuticals have the potential to cause effects on aquatic organisms. Sewage treatment plants, that are designed to meet statutory discharge consents for nutrients, are increasing in number. These plants, capable of biological nutrient removal, are understudied for the removal efficiencies of pharmaceuticals. This thesis presents research findings on the behaviour, fate and removal of selected pharmaceuticals in a bespoke laboratory rig, and in operational biological nutrient removal sewage treatment plants. Pharmaceuticals possessing a broad range of physical and chemical properties were selected for this research, they included: salicylic acid, caffeine, propranolol, diclofenac and carbamazepine. Sensitive chromatographic methods were developed to quantify the analytes in a laboratory sequencing batch reactor rig and in operational plants. Radiolabelled 14C isotopes of salicylic acid, caffeine, propranolol and diclofenac were dosed into the laboratory rig. The compounds exhibited different behaviours during a simulated sewage treatment process. Salicylic acid and caffeine produced the highest amount of biodegradation, with 25.2% and 14.5% of the radiolabel mineralised to 14CO2 in the rig. However, parent degradation is likely to have been higher, since neither compound could be detected in the effluent by specific chemical analysis. These findings were replicated in the operational sewage treatment plants, with > 97% removal of both pharmaceuticals, in all three plants investigated. Propranolol and diclofenac were less affected by biodegradation processes, and produced 3.7% and 0.2% mineralisation, respectively, in the laboratory rig. Furthermore, 33.8% of the radioactivity associated to 14C propranolol was detected in the rig solids. These compounds showed insignificant removal from two operational plants; 6.8% and 20.9% (propranolol) and -0.9% and -39.4% (diclofenac). Monitoring of operational plants showed that concentrations of propranolol were highest in the activated sludge tanks at all three sites. This supports the findings from the rig, that propranolol interacts with the sludge, which might be more significant in plants with lower sludge wastage rates, such as sequencing batch reactors. This could have implications for the terrestrial environment, and therefore, terrestrial risk assessments should be refined accordingly. Monitoring of the operational sewage treatment plants highlighted the widespread presence, and recalcitrant behaviour, of carbamazepine during biological sewage treatment. Future work should focus on investigating the mechanisms of removal, of this pharmaceutical in the laboratory sequencing batch reactor. This work highlighted the problems biological systems face in effectively removing recalcitrant pharmaceuticals. Advanced wastewater treatment should be considered, if complete removal is desired.

Pharmaceuticals in the aquatic environment is an emerging issue and the risks they pose are mostly unknown. They are used in large amounts throughout the world and can enter the environment, as the active metabolite or unmetabolised, through excretion by people and improper disposal. As these drugs are designed to have specific biological effects in a specific organism (as well as sometimes having other non-specific side effects), their potential to cause effects within the environment is great. Clofibric acid (the major metabolite of the lipid lowering drug, Clofibrate) is non-biodegradable, highly motile, very persistent and frequently detected at μg/I levels in the environment. I studied possible effects of clofibric acid in fish, using different experimental approaches and endpoints. The studies involve two different species, and for one of these species, fish at different stages of development. The chapters within this thesis have presented the first evidence (albeit preliminary) of clofibric acid having effects on both adult and embryo fish. When fathead minnow embryos were exposed to clofibric acid, the effects seen included changes in the eggshell, time to hatch, hatchability, mortality and viability. Adult fathead minnow were similarly exposed and significant effects on specific parameters were also observed. These included effects on lipid metabolism, steroidogenesis and spermatogenesis - thought to be via cholesterol transport - as well as significant effects on the expression of several genes involved in lipid metabolism and detoxification. Exposure of juvenile (sexually undifferentiated) bream also found significant differences in some endpoints. Other results suggested, less pronounced effects of clofibric acid on some other parameters. The results from this research show that there are effects of clofibric acid in pathways which were not only unexpected in fish (for example, steroidogenesis, spermatogenesis and gene expression), but also at concentrations below those previously shown to have any biological effects on fish. These effects indicate that clofibric acid may potentially have an impact on fish fecundity, and even more worryingly, on human health for those people prescribed it.

In der Broschüre wird ein neues Verfahren vorgestellt, welches zur Bewertung und Minderung von Stoffausträgen aus Ackerflächen in Oberflächengewässer entwickelt wurde. Dazu werden in einem ersten Schritt Gewässer und angrenzende Ackerschläge hinsichtlich Nutzung, Schutzstreifen und Gefahrenpunkte erfasst. In einem zweiten Schritt werden ein N- und ein P-Index berechnet, die das Stoffaustragsrisiko angeben. Die beiden Indices basieren auf einfach zu erhebenden Daten und auf einfachen Berechnungen. In einem dritten Schritt werden Maßnahmen zur Risikominderung empfohlen und deren Wirksamkeit prognostiziert. Anhand dieser Prognose können passende Schutzmaßnahmen ausgewählt werden. Das Verfahren wurde an zwei Oberflächenwasserkörpern in Sachsen erprobt. Es kann ebenso die Identifikation von Flächen mit hohem Stoffaustragsrisiko unterstützen.

In der Broschüre wird ein neues Verfahren vorgestellt, welches zur Bewertung und Minderung von Stoffausträgen aus Ackerflächen in Oberflächengewässer entwickelt wurde. Dazu werden in einem ersten Schritt Gewässer und angrenzende Ackerschläge hinsichtlich Nutzung, Schutzstreifen und Gefahrenpunkte erfasst. In einem zweiten Schritt werden ein N- und ein P-Index berechnet, die das Stoffaustragsrisiko angeben. Die beiden Indices basieren auf einfach zu erhebenden Daten und auf einfachen Berechnungen. In einem dritten Schritt werden Maßnahmen zur Risikominderung empfohlen und deren Wirksamkeit prognostiziert. Anhand dieser Prognose können passende Schutzmaßnahmen ausgewählt werden. Das Verfahren wurde an zwei Oberflächenwasserkörpern in Sachsen erprobt. Es kann ebenso die Identifikation von Flächen mit hohem Stoffaustragsrisiko unterstützen.