by Tsui Tsz Ki, Martin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 119-138). / Abstracts in English and Chinese. / Acknowledgements --- p.I / Abstract --- p.III / Table of Contents --- p.VII / List of Tables --- p.XII / List of Figures --- p.XIV / Abbreviations --- p.XVI / Chapter Chapter 1 --- General Introduction / Chapter 1.1 --- Research Background --- p.1 / Chapter 1.1.1 --- General description of glyphosate --- p.1 / Chapter 1.1.2 --- Physical and chemical properties of glyphosate --- p.2 / Chapter 1.1.3 --- Commercial formulations based on glyphosate --- p.3 / Chapter 1.1.4 --- Overview of ecotoxicological studies of glyphosate-based formulations --- p.4 / Chapter 1.1.4.1 --- Aquatic toxicity of glyphosate-based formulations --- p.4 / Chapter 1.1.4.2 --- Environmental fate of glyphosate-based formulations in waters --- p.12 / Chapter 1.1.5 --- Interaction of glyphosate and other substances --- p.14 / Chapter 1.2 --- Overview of Aquatic and Sediment Toxicology --- p.16 / Chapter 1.2.1 --- Aquatic toxicology --- p.16 / Chapter 1.2.2 --- Introduction to sediment toxicology --- p.19 / Chapter 1.3 --- "Significance, Outline and Objectives of the Present Study" --- p.20 / Chapter 1.3.1 --- Significance of the research --- p.20 / Chapter 1.3.2 --- Thesis outlines and research objectives --- p.22 / Chapter Chapter 2 --- Aquatic Toxicity of Glyphosate-based Herbicides to Different Organisms and the Effects of Environmental Factors / Chapter 2.1 --- Introduction --- p.25 / Chapter 2.2 --- Materials and Methods --- p.26 / Chapter 2.2.1 --- Test organisms --- p.26 / Chapter 2.2.2 --- Test chemicals --- p.27 / Chapter 2.2.3 --- Comparison between different organisms --- p.27 / Chapter 2.2.4 --- Environmental factors in modifying Roundup® toxicity --- p.30 / Chapter 2.2.5 --- Analysis of glyphosate concentration --- p.31 / Chapter 2.2.6 --- Validity of tests and statistical analyses --- p.32 / Chapter 2.3 --- Results --- p.32 / Chapter 2.3.1 --- Comparison between different groups of organisms --- p.32 / Chapter 2.3.2 --- Environmental factors in modifying Roundup® toxicity to C.dubia --- p.35 / Chapter 2.4 --- Discussion --- p.36 / Chapter 2.4.1 --- Toxicity of glyphosate to photo synthetic organisms --- p.36 / Chapter 2.4.2 --- pH-associated toxicity of glyphosate --- p.37 / Chapter 2.4.3 --- High potency of surfactant --- p.38 / Chapter 2.4.4 --- Effects of environmental factors on Roundup® toxicity --- p.38 / Chapter 2.5 --- Conclusions --- p.39 / Chapter Chapter 3 --- "Toxicity of Rodeo®, Roundup® Biactive and Roundup® to Water-column and Benthic Organisms and the Effect of Organic Carbon on Sediment Toxicity" / Chapter 3.1 --- Introduction --- p.41 / Chapter 3.2 --- Materials and Methods --- p.43 / Chapter 3.2.1 --- Test chemicals --- p.43 / Chapter 3.2.2 --- Test organisms --- p.43 / Chapter 3.2.3 --- Toxicities to water-column and benthic organisms --- p.44 / Chapter 3.2.4 --- Effect of sediment organic carbon --- p.45 / Chapter 3.2.5 --- Statistical analyses --- p.48 / Chapter 3.3 --- Results --- p.48 / Chapter 3.3.1 --- Toxicities to water-column and benthic organisms --- p.48 / Chapter 3.3.2 --- Effect of sediment organic carbon --- p.49 / Chapter 3.4 --- Discussion --- p.54 / Chapter 3.4.1 --- Different sensitivities between water-column and bethic animals --- p.54 / Chapter 3.4.2 --- Relative toxicities of three herbicides --- p.56 / Chapter 3.4.3 --- Route of exposure of herbicides in sediment to organisms --- p.57 / Chapter 3.4.4 --- Sediment toxicity of glyphosate-based formulations --- p.58 / Chapter 3.4.5 --- Effect of organic carbon on partitioning and toxicity --- p.60 / Chapter 3.5 --- Conclusions --- p.61 / Chapter Chapter 4 --- Joint Toxicity of Glyphosate and Several Selected Environmental Pollutants to Ceriodaphnia dubia / Chapter 4.1 --- Introduction --- p.63 / Chapter 4.2 --- Materials and Methods --- p.65 / Chapter 4.2.1 --- Test organisms and toxicity tests --- p.65 / Chapter 4.2.2 --- Test chemicals --- p.66 / Chapter 4.2.3 --- Experiment I: Joint acute toxicity of Roundup® and nine toxicants --- p.66 / Chapter 4.2.4 --- Experiment II： Effect of IPA salt of glyphosate alone at EEC on toxicities of heavy metals --- p.67 / Chapter 4.2.5 --- Basic water properties and chemical analyses --- p.69 / Chapter 4.2.6 --- Statistical analyses --- p.70 / Chapter 4.3 --- Results --- p.70 / Chapter 4.3.1 --- General conditions and recovery for spiked chemicals --- p.70 / Chapter 4.3.2 --- Experiment I: Joint acute toxicity of Roundup® and nine toxicants --- p.71 / Chapter 4.3.3 --- Experiment II: Effect of IPA salt of glyphosate alone at EEC on toxicities of heavy metals --- p.73 / Chapter 4.4 --- Discussion --- p.75 / Chapter 4.4.1 --- Interactions of Roundup® and other toxicants --- p.75 / Chapter 4.4.2 --- Joint toxicity of dissimilar chemicals --- p.77 / Chapter 4.4.3 --- Complexation of glyphosate with metals interactions between liquid/solid phases --- p.79 / Chapter 4.5 --- Conclusions --- p.83 / Chapter Chapter 5 --- Environmental Fate of Glyphosate and its Nontarget Impact: a Case Study in Hong Kong / Chapter 5.1 --- Introduction --- p.85 / Chapter 5.2 --- Materials and Methods --- p.87 / Chapter 5.2.1 --- Description of study sites --- p.87 / Chapter 5.2.2 --- Physicochemical characteristics of different matrices --- p.88 / Chapter 5.2.3 --- Continuous weather monitoring --- p.89 / Chapter 5.2.4 --- Herbicide applications --- p.89 / Chapter 5.2.5 --- Experimental designs --- p.90 / Chapter 5.2.5.1 --- Estuarine enclosure experiment --- p.90 / Chapter 5.2.5.2 --- Freshwater pond experiment --- p.92 / Chapter 5.2.6 --- Schedule of sample collection and sample storage --- p.92 / Chapter 5.2.7 --- Sample preparation --- p.94 / Chapter 5.2.7.1 --- Water samples --- p.94 / Chapter 5.2.7.2 --- Sediment samples --- p.94 / Chapter 5.2.8 --- Sample determination --- p.95 / Chapter 5.2.8.1 --- Pre-column derivatization --- p.95 / Chapter 5.2.8.2 --- High performance liquid chromatography analyses --- p.95 / Chapter 5.2.8.3 --- Calibration of glyphosate and AMPA --- p.95 / Chapter 5.2.8.4 --- Recovery of glyphosate in spiked samples --- p.96 / Chapter 5.2.9 --- Statistical analyses --- p.96 / Chapter 5.3 --- Results --- p.96 / Chapter 5.3.1 --- Site characteristics --- p.96 / Chapter 5.3.2 --- Weather conditions during herbicide application --- p.99 / Chapter 5.3.3 --- Chemical analyses --- p.100 / Chapter 5.3.4 --- In-situ toxicity tests --- p.104 / Chapter 5.4 --- Discussion --- p.106 / Chapter 5.4.1 --- Site-specific factor affecting the environmental fate --- p.106 / Chapter 5.4.1 --- Site-specific factor affecting the environmental fate of glyphosate --- p.106 / Chapter 5.4.2 --- Glyphosate in water and sediment --- p.106 / Chapter 5.4.3 --- Homogeneity of glyphosate in surface water and sediment --- p.109 / Chapter 5.4.4 --- Effect of weather conditions on environmental fate of glyphosate --- p.109 / Chapter 5.4.5 --- Biological impact of Roundup® --- p.110 / Chapter 5.5 --- Conclusions --- p.112 / Chapter Chapter 6 --- General Conclusions --- p.113 / References --- p.119