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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.
1

Heavy Metal Contamination from Landfills in Coastal Marine Sediments: Kiribati and New Zealand.

Redfern, Farran Mack January 2006 (has links)
Landfill leachates are a concern in the Pacific Region where they may contribute contaminants to the coastal marine environment. Poor waste management and pollution of coastal waters are amongst the major environmental problems in Kiribati, particularly in South Tarawa. An investigation of areas adjacent to coastal landfill sites; Betio, Kiribati and Auckland, New Zealand was undertaken. The Kiribati case study investigated metal contamination in marine sediments at an operational landfill while the New Zealand study was adjacent to a coastal landfill decommissioned in the 1970s. Surficial sediments (top 15 cm) were collected along transects. At both the New Zealand and Kiribati sites, 3 transects adjacent to the landfill and 1 control transect were sampled. The sediments were analyzed for particle size distribution, organic matter content, and Cd, As, Cr, Cu, Pb, Hg, Ni and Zn concentrations. The pH was also measured. The Kiribati study site had a groundwater pH of 7.14 - 8.85, and sediment materials were dominated by sand with a low organic matter content (1.60 - 2.21 %). At the Kiribati sites Cd, As, and Ni were below the detection limits. The Cr, Cu, Pb and Zn concentrations were lower at the Kiribati control transect than the landfill transects. Cr level decreased away from the landfill indicating the landfill as a possible source. However, Cu and Zn did not show any distribution pattern suggesting other potential sources (port and shipwrecks) may have contributed to the elevated levels. At the Kiribati landfill and control transects the Cr, As, Cd, Cu, Pb, Ni, and Zn concentration were below the Effects Range-Low (ERL) and the threshold Effects levels (TEL) of the Sediment Quality Guidelines (SQCs) of the National Oceanographic and Atmospheric Administration (NOAA) and the Florida Department of Environmental Protection, indicating no potential adverse ecological effects on the biota. At the Kiribati control site the Cr, As, Cd, Cu, Pb, Ni and Zn concentrations were within the background ranges published for clean reef sediment but the concentration at the landfill transects exceeded the background ranges. The concentration of mercury at both the control and landfill transects in Kiribati exceeded the Effects Range-Median (ERM) and the Probable Effects Level (PEL) of the SQGs indicating potential adverse ecological effects on the local benthic communities. The New Zealand study site sediments had a pH of 6.22 - 7.24, and comprised up to 90 % clay/silt, with an organic matter content of 5 - 22 %. At the New Zealand landfill transects Arsenic concentrations decreased away from the landfill indicating the landfill as a possible source. Other metals such as Cr did not show a pattern of distribution along the transects, or with depth, suggesting that the landfill was not the only source of these metals. There was a weak correlation between organic matter content, particle size distribution, and metal enrichment. At the New Zealand site, there were no marked differences in metal concentrations between the landfill and control transects suggesting the landfill was not the only source of metals and that the wider urban or industrial run-off may have contributed. All the metal concentrations, except Hg and Zn, exceeded the ERL and the TEL values indicating the potential for adverse ecological effects of metals on the benthic communities. At the New Zealand site the Hg and Zn concentrations exceeded both the ERM and PEL of the SQGs and are considered highly contaminated.
2

Oil Spills in New Zealand's Territorial Waters: Fence at the Top of the Cliff?

Hoeberechts, Veronica Anne January 2006 (has links)
Over the last four decades, there have been many catastrophic oil spills in the marine environment and these larger oil spills have often caused environmental devastation especially if they occurred in the coastal marine area. Serious ecological damage can also be caused from operational discharges, ballast and bilge water, from ships within territorial waters. Until now New Zealand has only had relatively minor oil spillages in its coastal waters, primarily from ships' discharge or accidental leaks in port. The possibility however of a major oil spill occurring within our coastal area is considerably higher today than 20 years ago as there has been a significant increase of all types of oil tankers/bulk carriers/container ships to New Zealand. New Zealand is an island nation that relies heavily on the marine environment for commercial operations such as fisheries and tourism and many New Zealanders enjoy recreational, aesthetic and spiritual ties to the coastal marine area. The sustainability of our territorial sea is therefore of paramount importance. A major oil spill could cause widespread ecological damage, cripple or destroy marine/tourism operations and ensure that the human values associated with the coast are lost, possibly for many years. The research reported here addresses the issue of oil spill preparedness and response in New Zealand's waters. A combination of a review of New Zealand's international commitments and domestic legislation and two case studies of high profile oil spills: the Poor Knights Islands Marine Reserve and the Jody F Millennium are used. The research identifies whether the present environmental legislation, that promotes sustainable management, is proactive in the prevention of a major oil spill and concludes that the New Zealand approach reflects a relatively strong Sustainable Imperative position rather than one of Sustainable Development. In implementation it relies heavily on co-management integrated at the regional council level.

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