Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1983. / Supervised by William D. Grant. Includes bibliographical references (leaves 201-205).

When a semi-infinite body of homogeneous fluid initially at rest behind a vertical retaining wall is suddenly released by the removal of the barrier the resulting flow over a horizontal or sloping bed is referred to as a dam-break flow. When resistance to the flow is neglected the exact solution, in the case of a stable horizontal bed with or without `tail water', may be obtained on the basis of shallow-water theory via the method of characteristics and the results are well known. Discrepancies between these shallow-water based solutions and experiments have been partially accounted for by the introduction of flow resistance in the form of basal friction. This added friction significantly modifies the wave speed and flow profile near the head of the wave so that the simple exact solutions no longer apply and various asymptotic or numerical approaches must be implemented to solve these frictionally modified depth-averaged shallow-water equations. When the bed is no longer stable so that solid particles may be exchanged between the bed and the water column the dynamics of the flow becomes highly complex as the buoyancy forces vary in space and time according to the competing rates of erosion and deposition. Furthermore, when the Froude number of the flow is close to unity perturbations in the height and velocity profiles grow into N-waves and the bed below develops ripples which act to sustain the N-waves in the fluid above. It is our intention here to study dam-break flows over erodible sloping beds as agents of sediment transport taking into account basal friction as well as the effects of particle concentrations on flow dynamics including both erosion and deposition. We shall consider shallow flows over initially dry beds and investigate the effects of changes in the depositional and erosional models employed as well as in the nature of the drag acting on the flow and the slope of the bed. These models include effects hitherto neglected in such studies and offer insights into the transport of sediment in the worst case scenario of the complete and instantaneous collapse of a dam. / Mathematics

When a semi-infinite body of homogeneous fluid initially at rest behind a vertical retaining wall is suddenly released by the removal of the barrier the resulting flow over a horizontal or sloping bed is referred to as a dam-break flow. When resistance to the flow is neglected the exact solution, in the case of a stable horizontal bed with or without `tail water', may be obtained on the basis of shallow-water theory via the method of characteristics and the results are well known. Discrepancies between these shallow-water based solutions and experiments have been partially accounted for by the introduction of flow resistance in the form of basal friction. This added friction significantly modifies the wave speed and flow profile near the head of the wave so that the simple exact solutions no longer apply and various asymptotic or numerical approaches must be implemented to solve these frictionally modified depth-averaged shallow-water equations. When the bed is no longer stable so that solid particles may be exchanged between the bed and the water column the dynamics of the flow becomes highly complex as the buoyancy forces vary in space and time according to the competing rates of erosion and deposition. Furthermore, when the Froude number of the flow is close to unity perturbations in the height and velocity profiles grow into N-waves and the bed below develops ripples which act to sustain the N-waves in the fluid above. It is our intention here to study dam-break flows over erodible sloping beds as agents of sediment transport taking into account basal friction as well as the effects of particle concentrations on flow dynamics including both erosion and deposition. We shall consider shallow flows over initially dry beds and investigate the effects of changes in the depositional and erosional models employed as well as in the nature of the drag acting on the flow and the slope of the bed. These models include effects hitherto neglected in such studies and offer insights into the transport of sediment in the worst case scenario of the complete and instantaneous collapse of a dam. / Mathematics

Thesis (Ph.D.)--University of Delaware, 2006. / Principal faculty advisor: James T. Kirby, Dept. of Civil & Environmental Engineering. Includes bibliographical references.

Thesis (M.S.)--University of North Carolina at Wilmington, 2006. / Vita. Includes bibliographical references (leaves: 60-63)

Brominated flame retardants (BFRs) has for many years been used in products to reduce their flammability, mainly in electronic products, textiles and construction materials. In 2003, Sweden imported 300 tons of brominated flame retardants. Leakage of these compounds has polluted natural environments. Fishes has shown increased contents of these substances, especially fat fish, since brominated flame retardants tends to accumulate in fatty tissues. They are also regarded as persistent and that gives them the ability to travel long distances. What also is really scary is that increased levels of brominated flame retardants have been detected in human breast milk. The knowledge of the brominated flame retardants is limited and not so much research has been done in this field. There are many reasons though, to keep the research going. Partly their structural resemblance to well-known toxics as PCB, but also their ability to accumulate in biological systems and enrich in food chains. In which way they affect humans we really don’t know yet. Experiments on mice have been done and behavioural disturbances were observed as well as a decrease in learning capacity. The BRFs chosen for this study are hexabromocyclododecan (HBCD) and a polybrominated diphenyl ether (PBDE) called pentabromodiphenylether (BDE 99). About 25 % of the flame retardants produced in the world every year, consists of the brominated ones. If we look at the PBDEs it’s mainly tetrabromodiphenylether (BDE 47), pentabromodiphenylether (BDE 99), octabromodiphenylether (BDE 205) and decabromodiphenylether (BDE 209) that are common flame retardants. As from July 1st 2006, PBDE was forbidden in electric and electronic products (15). January 1st 2007, a Swedish prohibition concerning the use of BDE-209 was established. BDE- 209 is not allowed on the Swedish market if the content of substance exceed 0,1 percent of weight (23). BDE-99 is classified as environmentally dangerous and a healthrisk. It´s not only toxic for waterliving organisms but also for humans if exposed during a long time (19). We shall develop a well functioning, reproducible and economic method to analyse HBCD and PBDE in sediment. It includes extraction, cleanup and sample analyses with a ECD (electron capture detector) equipped capillary gas chromatograph. Several analyses of adequate diluted standards has been analysed in a GC-ECD to find suitable temperature gradients. Then we produced spiked sediment samples with known amounts of standards. To homogenize the spiked samples we used a mixer. As a first step in the extraction we used acetone as a solvent. Then we used cyclohexane and NaCl (2%) to separate the nonpolar and polar substances from each other. Cleanup with concentrated sulphuric acid was done and for some samples we also used Florisil. To concentrate the extract it was evaporated with N2(g).The extract was then analysed in a GC-ECD and then the results was compared with the standards. The result of this project showed that our method of extraction is useful. We managed to extract 50 % HBCD, 30 % BDE-99 and 60 % BDE-99 (dried sediment).

Projektet baserades på analyser av Munksjöns sediment. Munksjön är belägen i centrala Jönköping och har under många decennier omgivits av miljöbelastande verksamheter. Detta har resulterat i att sjön är så starkt förorenad att den ligger på första plats i Länsstyrelsens 30-lista över prioriterade objekt i det regionala programmet för undersökning, utredning och åtgärder av förorenade områden i Jönköpings län. Den mest förorenade delen av sjön, fiberbanken, är belägen utanför Munksjö AB som tidigare släppt ut stora mängder fibermaterial och kvicksilver med sitt processvatten från papperstillverkningen. Analyserna har omfattat syreförbrukning och svavelinnehåll. Sedimentprovertogs från fyra lokaler i olika områden och djup. Metoden för syreförbrukningenarbetades fram genom olika försök för att få en linjär hastighet som motsvarar sjöns naturliga tillstånd. Den slutliga metoden utfördes med E-kolvar där botten täcktes med sediment och flaskan sedan fylldes med Milli-Q-vatten till kanten och förslöts med en gummipropp. Mätningar utfördes varje vardag med syrgaselektrod i två veckor, och därefter utfördes en mätning efter ytterligare en vecka. Metoden för svavelinnehåll innebar natriumhydroxidfusion och spektrofotometrisk analys. Resultatet för syreförbrukningen visade att områden kring fiberbanken har enhögre syreförbrukningshastighet än den södra, mindre förorenade, delen avsjön. Den högsta syreförbrukningshastigheten, 4,07*10-3 mg O2 per gram och timme, uppmättes på sedimentet från området närmast fiberbanken. Den lägsta hastigheten, 1,61*10-3 mg O2 per gram och timme, uppmättes i södra delen av sjön. Syreförbrukningshastigheten bestämdes också per cm2. Resultatet för svavelinnehållet visade att en lokal vid djupområdet i sjön hade högst svavelinnehåll, 15,2 g/kg torrsubstans. Eftersom den ligger nära fiberbanken är det höga svavelinnehållet bra, då det binder till sig förekommande metaller så att de inte påverkar de levande organismerna i sjön. / The project was based on analyses of the sediments of Lake Munksjön in Jönköping, Sweden. Lake Munksjön is located in central Jönköping and has for many decades been surrounded by environmentally damaging enterprises. This has resulted in the lake being so strongly polluted that it is placed first on a list from The County Administrative Board over priority objects in the regional programme for inquiry, investigation and intervention of polluted areas in Jönköping County. The most heavily polluted part of the lake, the fibre bank, is situated outside Munksjö Inc. which has previously emitted large amounts of fibre and mercury with the process water from the paper mill’s manufacturing process. The analyses have covered oxygen consumption rate and sulphur content. Sediment samples were taken from four sampling points in different areas andat different depths. The method for measuring oxygen consumption rate was developed through several tests to achieve a linear velocity that also corresponds to the natural condition of the lake. The final method was performed using E-flasks were the bottom was covered with sediment and the flask filled with Milli-Q-water and stopped with a rubber plug. Measurements were taken every weekday with an oxygen electrode for two weeks, with one extra measurement after another week. The method for analysing sulphur content included sodium hydroxide fusion and spectrophotometric analysis. The result for oxygen consumption showed that the areas around the fibre bank have a higher oxygen consumption rate than the area in the southern, less polluted, part of the lake. The highest oxygen consumption rate, 4.07*10-3 mg O2 per gram dry substance and hour, was found in the sediment from the area closest to the fibre bank. The lowest rate, 1.61*10-3 mg O2 per gram dry substance and hour, was found in the sediments from the southern part of the lake. Oxygen consumption per cm2 and hour was also determined. The result for sulphur content showed that a sampling point by the deep area of the lake had the highest sulphur content, 15.2 g/kg dry substance. Due to the close proximity of the fibre bank the high sulphur content is good, as sulphides bind metals so they do not affect the living organisms in the lake.

Degradation of streams in urban-rural fringe regions occurs through complex interactions between hydrological, physical, chemical and biological mechanisms of the stream environment and surrounding landscape. Biological monitoring using macroinvertebrates may capture the complex and cumulative influences of land activity on the stream environment. The Salmon River catchment in the township of Langley, British Columbia, Canada straddles urban and rural environments in the Lower Fraser Valley. To date the Salmon River catchment has been subject to several environmental surveys. Following these earlier investigations, this study quantified relationships between the stream environment and changing land activity, across multiple scales, from 1975 to 2005, using macroinvertebrates as environmental integrators. Current and historical water, sediment, and macroinvertebrate information along with land use and land-cover evaluations were used to quantify relationships between the macroinvertebrate community and land activity in the catchment. Spatial and seasonal results for specific conductivity (a total dissolved ion indicator) and NO������-N and PO����� (nutrient indicators) traced groundwater and overland inputs to the stream environment. Nitrate guideline exceedances occurred at groundwater-influenced sites. Elevated sediment trace metal concentrations and Zn guideline exceedances occurred mid-reach in the catchment. Peak total macroinvertebrate and sensitive taxa abundance occurred mid-reach in the catchment in 2005, while richness and proportional sensitive abundance peaks were seen at groundwater-influenced sites. The dominance of tolerant to moderately pollution tolerant taxa occurred throughout. Despite historical water quality concerns at groundwater-influenced sites, greater shifts in community composition occurred in headwaters regions. Patterns of land use and land cover changed in sensitive areas (i.e. above aquifer and in the headwaters). A greater number of correlations between land activity and macroinvertebrate measures occurred at streams sites with 100 m buffers. The abundance of sensitive taxa positively correlated with the amount of agricultural land use, while rarefaction declined. Several Macroinvertebrate functional feeding groups correlated positively to forest cover, while sensitive taxa abundance and Zn concentrations declined. Results suggest continued water quality and sediment trace metal concerns, while macroinvertebrate results point to nutrient enrichment and greater historical variability in headwaters regions. Agricultural activity appears to have a stronger influence on aspects of the stream environment despite the presence of urban-rural land activity.

The aim of this study was to get a better knowledge of the metal pollution and the mining history of the Falun area. It adds new information on the geochemistry of the lakes and the beginning of mining in the Falun region, together with the influence of early land use. The main focus is on three lakes Hagtjärnen, Stugutjärnen and Nästjärnen, which were previously dated and analyzed regarding acidification by Anna Ek. Additional supporting information is provided from records from 10 other lakes, which are located at distances between 0-27 km from the Falun Copper mine. Another specific focus is on the lake Tisken, which has been assumed over the past 50 years to represent faithful historical record of mining in the Falun area. In this study this lake record was dated and analyzed, too. The analyses of all the lakes included resulted in four significant phases of environmental change, indicating the start of agriculture and mining, the development of each sector, as well as the sharp increase in pollution in the modern time period. Phase I covers the time period A.D. 700-1000 and represents the time of the early beginning of land use and small scale mining activities. Phase II represents the time between A.D. 1200 to 1450, which is dominated by an ongoing development of mining and a sharp increase in metal concentrations and occurrence of cultivated plants and plants favored by disturbance from A.D. 1450 onwards. The third phase, representing the year A.D. 1540, clearly displays another period of sharp increases among the metal concentrations, which coincides with a peak in Cu production volumes. Phase IV covers the time period A.D. 1750-1900, referred to as Modern time, and features a clear increase in Pb pollution, which is linked to the introduction of tetra ethyl Pb in the 1970s. Other metals increase also, together with cultivated plants like cereals, indicating an ongoing expansion of mining and agriculture. The results also indicate that Cu was not emitted as far as other elements, like for example Pb, which led to great pollution only in the lakes close to the Falun mine. Another important finding is that the lake Tisken does not represent a continual historical record, because the sediment is not a chronological sequence and instead likely represents mostly a catastrophic input of debris of mixed age. The C-14 dating shows, that the sediment is mixed and disturbed in Tisken. As a consequence, the long-standing interpretation of Tisken’s sediment record as an archive for the historical start and late development of mining at the Falun copper mine is incorrect

Radiocarbon datings in a previous study suggested that Moshyttan in Nora bergslag is the oldest blast furnace in Sweden and Europe. The aim of this study was specifically to study the origin of the Moshyttan blast furnace to answer the question: when was the blast furnace at Moshyttan established? To this end, a 2.5 m sediment record was collected from Fickeln, a lake 600 m downstream of Moshyttan, in March 2012. The geochemical properties of the sediment record were analyzed for major and trace elements using XRF. The organic content was calculated from the ash residue following the mercury analyses as a proxy for organic matter. Pollen and charcoal were analyzed using a standardized method. A age- depth model was created based on four radiocarbon datings of the sediment profile. The pollen data suggest that early land use consisted of forest grazing from about AD 220, and agriculture from about AD 880. An increase in Pb and charcoal particles about AD 880 indicates early metallurgy in the area. The first significant evidence of the establishment of a blastfurnace was between AD 1020 and AD 1090 marked by a decrease in organic content combined with a strong increase of ore related metals such as Pb, Zn, Cu and a strong increase of charcoal particles. Within the uncertainty of the age-depth modeling, the results from this study offers support to Wetterholms radiocarbon datings, thus making Moshyttan the oldest known blast furnace in Sweden and Europe.