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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
371

Peat Deposits of Moreton Bay:Natural Archives of Environmental Pollution

Jiajia Zheng Unknown Date (has links)
Two ombrotrophic peat bogs (NC2 and BL2) from North Stradbroke Island, Australia, were precisely dated using 210Pb and analyzed by scanning electron microscopy. Sub-samples were total digested and sequentially leached for trace and major elements concentrations using ICP-MS and ICP-OES. Total Pb concentrations in both profiles increased with the time. PAAS normalized REE patterns were characterized by relatively flat patterns, with slight enrichment in LREE, and a significant negative Eu anomaly. The temporal changes in metal concentrations, 206Pb/207Pb ratios, REEs, and ash content observed in the two profiles suggest three different periods with distinct conditions in terms of dust provenance and atmospheric pollution: (1) Pre-anthropogenic (pre-1842); (2) Early industrial (from 1840s to 1920s); (3) Industrial (post-1930s). Ombrotrophic peat bogs may be reliable archives of environmental pollution, but also shows that adjacent sites may provide contrasting evidence. Despite their close proximity, the two sites show different trends in metal deposition. Metals in NC appear to be largely bound to minerals and inorganic materials, while in BL they are mainly organic-related. Indeed the peculiar behaviour of Pb in the BL profile suggests that biological process may cause Pb isotopic fractionation. Ash contents, texture, Pb isotopic compositions, Sb/Pb values, patterns of selected trace elements (Pb, Cu, Zn, Cd, Cr, Co, Sb, Ni, Se, As, Be and Mo), and their leaching behaviours suggests that NC and BL are chemically different types of peat bogs. NC peat bog is an open sink for elements, and can be used to define regional anthropogenic impacts. In contrast, the BL site appears to be influenced by local natural and anthropogenic processes and activities, such as changes in land use. Furthermore, it demonstrated that only some of the environmental-related trace elements preserve their original depositional record. Arsenic, Be, Co, and Zn are highly mobile under weak acid conditions, and are therefore not suitable for assessing temporal trends of pollution. Cadmium, Ni, and V may also be highly mobile under certain conditions. In contrast, Pb, Cu, Cr, Mo, and Sb are not subject to vertical migration, and are useful for establishing the pollution record of ombrotrophic peat bogs.
372

Cadmium in newborns : bioavailability from infant food studied in a rat pup, a piglet and a human intestinal cell line model /

Eklund, Gunilla, January 2003 (has links) (PDF)
Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv., 2003. / Härtill 4 uppsatser.
373

Organic vs. inorganic selenium in farm animal nutrition with special reference to supplementation of cattle /

Ortman, Kerstin, January 1900 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 5 uppsatser.
374

Nutrition and immune response in periparturient dairy cows : with emphasis on micronutrients /

Meglia, Guillermo Esteban, January 2004 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2004. / Härtill 4 uppsatser.
375

Nutrient and trace element flows and balances at the Öjebyn dairy farm : aspects of temporal and spatial variation and management practices /

Bengtsson, Helena, January 2005 (has links) (PDF)
Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv. / Härtill 4 uppsatser.
376

Competitive binding of metal ions by humic substances in model systems and in freshwaters /

Mandal, Rupasri, January 1900 (has links)
Thesis (Ph.D.) - Carleton University, 2002. / Includes bibliographical references (p. 188-198). Also available in electronic format on the Internet.
377

Paleoenvironmental recostruction of James and Granite Lakes in the Temagami region of Northeastern Ontario : from the retreat of the Laurentide ice sheet to the present /

Boudreau, Robert E. A. January 1900 (has links)
Thesis (Ph. D.)--Carleton University, 2004. / Includes bibliographical references. Also available in electronic format on the Internet.
378

Metal speciation in natural water: evaluating kinetics versus equilibrium /

Al-Fasfous, Ismail January 1900 (has links)
Thesis (Ph.D.) - Carleton University, 2005. / Includes bibliographical references (p. 292-309). Also available in electronic format on the Internet.
379

Biogeochemical characterization of a wetland impacted by alkaline mine tailings located in North Cobalt, Ontario /

Kelly, Jenifer, January 1900 (has links)
Thesis (M.Sc.) - Carleton University, 2006. / Includes bibliographical references (p. 142-146). Also available in electronic format on the Internet.
380

Binding of metals to macromolecular organic acids in natural waters : does organic matter? /

van Schaik, Joris W. J., January 2008 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 4 uppsatser.

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