published_or_final_version / Applied Geosciences / Master / Master of Science

The present study aimed to determine whether stable isotope techniques can be universally applied to detect landfill leachate contamination in aquatic systems. Results of analysis of ��C in dissolved inorganic carbon ([delta]��C-DIC), deuterium and �⁸O in water ([delta]D-H₂O and [delta]�⁸O-H₂O), and �⁵N of dissolved inorganic nitrogen components ([delta]�⁵N-NH₄⁺ and [delta]�⁵N-NO₃⁻) were presented for leachate, surface, and ground water samples collected from seven landfills located throughout New Zealand between 2003 and 2006. The unique conditions within a landfill lead to measurable fractionations in the isotopic ratios of the products of degradation. Results of isotope and ancillary parameter analyses enabled the discernment of different types of leachate, resulting from different microbial processes within the landfill environment. The isotopic characterisation of leachate enabled improved interpretation of geochemical data from potentially impacted surface and ground waters, and provides useful insight to landfill development for landfill operators. A general isotopic fingerprint delineated by [delta]��C-DIC and [delta]D-H₂O values showed leachate to be isotopically distinct from uncontaminated surface and ground water for samples analysed in the present study. However, not all water samples identified as leachate-impacted via site-specific assessments exhibited isotopic values that overlapped with the general leachate fingerprint. This highlights the need to investigate each site individually, within the context of a possibly global leachate isotope signature. Site-specific investigations revealed the effectiveness of applying [delta]�⁸O-H₂O and [delta]�⁵N-NH₄⁺ or [delta]�⁵N-NO₃⁻, in addition to [delta]��C-DIC and [delta]D-H₂O analyses, to the detection of leachate impact on aquatic systems. Furthermore, ancillary parameters such as alkalinity and ammonium concentration enabled the construction of simple isotope mixing models for an estimate of the quantity of leachate contribution. Results of isotopic investigations of stream biota suggested potential for the development of bio-indicators to monitor leachate influence on aquatic ecosystems in landfill-associated streams. The present study demonstrated the probative power of stable isotope techniques applied to investigations of leachate impact on landfill-associated aquatic systems.

Thesis (M. Phil.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 119-123).

Thesis (DTech. degree in Environmental management.)-Tshwane University of Technology, 2008. / Aims to determine the presence and levels of common polybrominated diphenyl ethers primarily in landfill leachates, but as well as sediment and groundwater (boreholes / wells around the landfill) from selected landfill sites in order to provide baseline data required to protect water resources against such chemicals.

published_or_final_version / Civil Engineering / Master / Master of Philosophy

My research uses a case study of Hemudu culture (7,000-5,000 BP) in eastern China to explore technological constraints of earth-working implements as a factor to explain the prolonged processes towards Neolithic agricultural land use and sedentary settlements. Early Hemudu populations lived in small villages and cultivated rice in the lowlands. They employed earth-working implements made from water buffalo scapulae; however, these implements were replaced with stone variants after 6,000 BP. These phenomena invited the following questions: (1) how did bone earth-working implements become a tradition and persist until 6,000 BP; (2) why was use of these artifacts replaced by use of stone spades; and (3) how did the choices of earth-working implements affect land use? Following ideas from Human Behavioral Ecology, Dual-Inheritance Theory, and Behavioral Archaeology, I examined bone implements' use contexts, raw material availability and procurement, costs and benefits in manufacture, techno-functional performance characteristics, and the Hemudu people's social learning strategies. These investigations involved soil science, bone and stone technologies, use-wear analysis, and zooarchaeology, along with many controlled experiments. Multiple sources of evidence led to the conclusion that the early adoption of bone spades was encouraged by scapulae's convenient morphology and acquisition, and they fulfilled the functional needs at the beginning of Kuahuqiao (8,200-7000 BP) and Hemudu exploitation of lowland environments. Frequency-dependent bias helped ensure the persistence of bone spades in Hemudu even when raw material became scarce and other artifacts would have provided marginal functional advantages. This tradition imposed significant technical and conceptual constraints that inhibited the communities from adopting other forms of agriculture and settlement construction. My research has broad implications to archaeological theories and methods for studying technological choices and our understanding of the pathways to agriculture and sedentism. It shows that although Human Behavioral Ecology and Dual-Inheritance Theory are useful for studying and interpreting technological choices, applying the framework proposed by Behavioral Archaeology helped lead to a stronger argument. Many of the analytical tools that I developed in this project can be used to investigate relevant questions in other times and cultures. My experimental designs can also be used as templates in future research.

&Ccedil / ayirhan soil is a collapsible soil. Collapsible soils are generally unsaturated, low-density soils with high voids between grains where the binding agents are sensitive to saturation. When exposed to water, binding agents break, soften or dissolve such that the soil grains shear against each other and reorient in denser configurations. This reconfiguration causes a net decrease in the soil mass, resulting in large and often unexpected settlements, which can totally destroy roads, underground utilities, and structures and alter surface drainage. Uses of collapsible soils as a natural construction material in fills or embankments also may cause serious stability problems. In this study, an extensive research program was carried out to investigate some geotechnical properties such as compaction, triaxial strength, bearing ratio and permeability of collapsible soil, found in &Ccedil / ayirhan Thermal Power Plant area, by treating with Class C fly ash and desulphogypsum (thermal power plant by-products that are to be handled for environmental reasons) in various proportions. The study has revealed that 20% and 25% fly ash or 5% desulphogypsum treatments (by dry weight of the mixture) improve the strength and bearing characteristics of &Ccedil / ayirhan soil.

The present study aimed to determine whether stable isotope techniques can be universally applied to detect landfill leachate contamination in aquatic systems. Results of analysis of ��C in dissolved inorganic carbon ([delta]��C-DIC), deuterium and �⁸O in water ([delta]D-H₂O and [delta]�⁸O-H₂O), and �⁵N of dissolved inorganic nitrogen components ([delta]�⁵N-NH₄⁺ and [delta]�⁵N-NO₃⁻) were presented for leachate, surface, and ground water samples collected from seven landfills located throughout New Zealand between 2003 and 2006. The unique conditions within a landfill lead to measurable fractionations in the isotopic ratios of the products of degradation. Results of isotope and ancillary parameter analyses enabled the discernment of different types of leachate, resulting from different microbial processes within the landfill environment. The isotopic characterisation of leachate enabled improved interpretation of geochemical data from potentially impacted surface and ground waters, and provides useful insight to landfill development for landfill operators. A general isotopic fingerprint delineated by [delta]��C-DIC and [delta]D-H₂O values showed leachate to be isotopically distinct from uncontaminated surface and ground water for samples analysed in the present study. However, not all water samples identified as leachate-impacted via site-specific assessments exhibited isotopic values that overlapped with the general leachate fingerprint. This highlights the need to investigate each site individually, within the context of a possibly global leachate isotope signature. Site-specific investigations revealed the effectiveness of applying [delta]�⁸O-H₂O and [delta]�⁵N-NH₄⁺ or [delta]�⁵N-NO₃⁻, in addition to [delta]��C-DIC and [delta]D-H₂O analyses, to the detection of leachate impact on aquatic systems. Furthermore, ancillary parameters such as alkalinity and ammonium concentration enabled the construction of simple isotope mixing models for an estimate of the quantity of leachate contribution. Results of isotopic investigations of stream biota suggested potential for the development of bio-indicators to monitor leachate influence on aquatic ecosystems in landfill-associated streams. The present study demonstrated the probative power of stable isotope techniques applied to investigations of leachate impact on landfill-associated aquatic systems.

Thesis (M.S.)--University of Texas at El Paso, 2008. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.

Thesis (M.P.A.)--University of Hong Kong, 1999. / Includes bibliographical references (leaves i-v).