Lai, Yuk Fo. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 169-191). / Abstracts in English and Chinese. / Abstract --- p.i / Abstract (in Chinese) --- p.iv / Dedication --- p.v / Acknowledgement --- p.vi / Table of contents --- p.viii / List of tables --- p.xii / List of figures --- p.xiii / List of plates --- p.xv / List of symbols and abbreviations --- p.xvi / Chapter Chapter One --- Introduction / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Research background --- p.1 / Chapter 1.2.1 --- Wetlands and water quality --- p.1 / Chapter 1.2.2 --- The role of sediments in eutrophication control --- p.3 / Chapter 1.2.3 --- Wetlands in ecological mitigation --- p.4 / Chapter 1.2.4 --- Previous studies of wetland pollution in Hong Kong --- p.6 / Chapter 1.3 --- Conceptual framework --- p.8 / Chapter 1.4 --- Objectives of the study --- p.12 / Chapter 1.5 --- Significance of study --- p.13 / Chapter 1.6 --- Organization of the thesis --- p.14 / Chapter Chapter Two --- Literature Review / Chapter 2.1 --- Introduction --- p.15 / Chapter 2.2 --- Quantification of phosphorus retention in wetlands --- p.16 / Chapter 2.2.1 --- Input-output concentration approach --- p.16 / Chapter 2.2.2 --- Mass balance approach --- p.18 / Chapter 2.2.3 --- Phosphorus removal efficiency --- p.19 / Chapter 2.3 --- Phosphorus sorption by wetland sediments --- p.20 / Chapter 2.3.1 --- Sorption and its significance --- p.20 / Chapter 2.3.2 --- Phosphorus sorption maxima --- p.22 / Chapter 2.3.3 --- Adsorption-desorption equilibrium --- p.23 / Chapter 2.3.4 --- Phosphorus sorption kinetics --- p.24 / Chapter 2.4 --- Phosphorus exchange across the sediment-water interface --- p.24 / Chapter 2.4.1 --- Phosphorus mobilization and transport mechanisms --- p.25 / Chapter 2.4.2 --- Phosphorus flux from aquatic sediments --- p.26 / Chapter 2.5 --- Phosphorus fractionation in wetland sediments --- p.29 / Chapter 2.5.1 --- Major sediment phosphorus fractions --- p.29 / Chapter 2.5.2 --- Phosphorus fractionation methods --- p.30 / Chapter 2.5.3 --- Relationships between phosphorus fractions and bioavailability . --- p.32 / Chapter 2.6 --- Factors affecting sediment-water phosphorus exchange --- p.33 / Chapter 2.6.1 --- pH --- p.34 / Chapter 2.6.2 --- Redox potential --- p.34 / Chapter 2.6.3 --- Temperature --- p.35 / Chapter 2.6.4 --- Salinity --- p.35 / Chapter 2.6.5 --- Sediment properties --- p.36 / Chapter Chapter Three --- Methodology / Chapter 3.1 --- Overall study approach --- p.38 / Chapter 3.2 --- Geographical setting of Hong Kong --- p.41 / Chapter 3.2.1 --- Climate --- p.42 / Chapter 3.2.2 --- Geology and landform --- p.44 / Chapter 3.2.3 --- Soil --- p.45 / Chapter 3.2.4 --- Vegetation --- p.45 / Chapter 3.3 --- Study sites --- p.46 / Chapter 3.3.1 --- Site selection --- p.46 / Chapter 3.3.2 --- Site description --- p.48 / Chapter 3.3.2.1 --- The Hong Kong Wetland Park --- p.48 / Chapter 3.3.2.2 --- Mai Po Marshes Nature Reserve --- p.50 / Chapter 3.4 --- Sampling strategy --- p.53 / Chapter 3.4.1 --- Sampling locations --- p.53 / Chapter 3.4.2 --- Sampling dates --- p.57 / Chapter 3.4.3 --- Sample collection and treatment --- p.58 / Chapter 3.5 --- Sample analysis --- p.60 / Chapter 3.5.1 --- Analysis of sediment samples --- p.61 / Chapter 3.5.1.1 --- Sediment texture --- p.61 / Chapter 3.5.1.2 --- Sediment pH --- p.61 / Chapter 3.5.1.3 --- Redox potential --- p.61 / Chapter 3.5.1.4 --- Sediment moisture --- p.62 / Chapter 3.5.1.5 --- Organic matter --- p.62 / Chapter 3.5.1.6 --- Total Kjeldahl nitrogen --- p.63 / Chapter 3.5.1.7 --- "Total Fe, Al, and P" --- p.63 / Chapter 3.5.1.8 --- "Oxalate-extractable Fe, Al, and P" --- p.63 / Chapter 3.5.2 --- Analysis of water samples --- p.64 / Chapter 3.5.2.1 --- "Water pH, conductivity, salinity, turbidity, temperature and DO" --- p.64 / Chapter 3.5.2.2 --- Orthophosphate --- p.64 / Chapter 3.5.2.3 --- Total nitrogen and phosphorus --- p.65 / Chapter 3.5.3 --- Determination of phosphorus exchange characteristics --- p.65 / Chapter 3.6 --- Statistical analysis --- p.65 / Chapter Chapter Four --- Phosphorus Fractionation in Wetland Sediments in Hong Kong / Chapter 4.1 --- Introduction --- p.67 / Chapter 4.2 --- Methodology --- p.68 / Chapter 4.2.1 --- Sample collection and analysis --- p.68 / Chapter 4.2.2 --- Phosphorus fractionation --- p.69 / Chapter 4.2.3 --- Statistical analysis --- p.72 / Chapter 4.3 --- Results and discussion --- p.72 / Chapter 4.3.1 --- Physico-chemical properties of sediments --- p.72 / Chapter 4.3.2 --- Physico-chemical properties of overlying water --- p.78 / Chapter 4.3.3 --- Phosphorus fractionation in sediments --- p.82 / Chapter 4.3.3.1 --- Phosphorus fractions in sediments of the Hong Kong Wetland Park --- p.82 / Chapter 4.3.3.2 --- Phosphorus fractions in sediments of the Mai Po Marshes --- p.89 / Chapter 4.3.3.3 --- Phosphorus fractions in relation to mobility and bioavailability --- p.96 / Chapter 4.4 --- Conclusions --- p.100 / Chapter Chapter Five --- Phosphorus Sorption by Wetland Sediments in Hong Kong / Chapter 5.1 --- Introduction --- p.103 / Chapter 5.2 --- Methodology --- p.104 / Chapter 5.2.1 --- Sample collection and analysis --- p.104 / Chapter 5.2.2 --- Batch incubation experiments --- p.105 / Chapter 5.2.3 --- Sorption kinetics --- p.106 / Chapter 5.2.4 --- Effects of selected environmental factors on phosphorus sorption --- p.106 / Chapter 5.2.5 --- Estimation of sorption parameters --- p.107 / Chapter 5.2.6 --- Statistical analysis --- p.109 / Chapter 5.3 --- Results and discussion --- p.109 / Chapter 5.3.1 --- Phosphorus sorption parameters of wetland sediments --- p.109 / Chapter 5.3.1.1 --- Phosphorus adsorption isotherms --- p.109 / Chapter 5.3.1.2 --- The role of sediments in phosphate buffering --- p.116 / Chapter 5.3.1.3 --- Relationships between phosphorus sorption parameters and physico-chemical properties of sediments --- p.121 / Chapter 5.3.2 --- Kinetics of phosphorus adsorption --- p.124 / Chapter 5.3.3 --- Effects of environmental factors on phosphorus sorption --- p.128 / Chapter 5.3.3.1 --- Effects of pH --- p.128 / Chapter 5.3.3.2 --- Effects of salinity --- p.131 / Chapter 5.3.3.3 --- Effects of temperature --- p.133 / Chapter 5.4 --- Conclusions --- p.136 / Chapter Chapter Six --- Phosphorus Flux from Wetland Sediments in Hong Kong / Chapter 6.1 --- Introduction --- p.139 / Chapter 6.2 --- Methodology --- p.140 / Chapter 6.2.1 --- Sample collection and analysis --- p.140 / Chapter 6.2.2 --- Core incubation experiments --- p.141 / Chapter 6.2.3 --- Estimation of phosphorus flux --- p.142 / Chapter 6.2.4 --- Statistical analysis --- p.142 / Chapter 6.3 --- Results and discussion --- p.143 / Chapter 6.3.1 --- Phosphorus flux from wetland sediments --- p.143 / Chapter 6.3.1.1 --- Phosphorus flux from sediments in the Hong Kong Wetland Park --- p.143 / Chapter 6.3.1.2 --- Phosphorus flux from sediments in the Mai Po Marshes --- p.147 / Chapter 6.3.2 --- Effects of redox conditions on sediment phosphorus flux --- p.152 / Chapter 6.4 --- Conclusions --- p.156 / Chapter Chapter Seven --- Conclusion / Chapter 7.1 --- Introduction --- p.159 / Chapter 7.2 --- Summary of major findings --- p.159 / Chapter 7.3 --- Limitations of study --- p.166 / Chapter 7.4 --- Suggestions for future study --- p.166 / References --- p.169