Contaminated Rivers: A Geomorphological-Geochemical Approach to Site Assessment and Remediation

1 Contaminated Rivers: An Overview 1.1 Introduction 1.2 Types of Contaminants 1.2.1 Organic Contaminants 1.2.2 Inorganic Contaminants 1.3 Sources of Contamination 1.4 The Dissolved Versus Particulate Load 1.5 Site Characterization, Assessment, and Remediation 1.6 The Geomorphological-Geochemical Approach 1.7 Summary 1.8 Suggested Readings 2 Sediment-Trace Metal Interactions 2.1 Introduction 2.2 Physical Partitioning of Trace Metals in Sediment 2.3 Chemical Partitioning of Trace Metals 2.3.1 Mechanistic Associations 2.3.2 Chemically Reactive Substrates 2.4 Elemental Speciation 2.5 Chemical Remobilization 2.6 Summary 2.7 Suggested Readings 3 Basin Processes 3.1 Introduction 3.2 Hillslope Hydrology 3.2.1 Direct Runoff Generation 3.2.2 Flood Hydrographs 3.3 Contaminant Transport Pathways 3.3.1 The Controlling Factors 3.3.2 Transport via Hortonian Overland Flow 3.3.3 Mapping Spatial Variations in Metal Sources 3.4 Hillslope Erosion 3.4.1 Basic Mechanics 3.4.2 Measurement of Erosion Rates 3.4.3 Prediction of Erosion Rates 3.5 Summary 3.6 Suggested Readings 4 The Water Column - Concentration and Load 4.1 Introduction 4.2 Temporal Variations in Concentration 4.2.1 Dissolved Constituents 4.3 Sediment and Contaminant Loads 4.3.1 Load Estimation 4.3.2 The Effective Transporting Discharge 4.4 Summary 4.5 Suggested Readings 5 The Channel Bed - Contaminant Transport and Storage 5.1 Introduction 5.2 Sediment Transport 5.2.1 Modes of Transport 5.2.2 Channelized Flow 5.2.3 Entrainment 5.3 Dispersal Processes 5.3.1 Hydraulic Sorting 5.3.2 Dilution and Exchange with the Floodplain 5.3.3 Sediment Storage and Exchange Mechanisms 5.3.4 Geochemical Processes and Biological Uptake 5.4 Downstream Patterns 5.5 Deposition and Storage along a Reach 5.5.1 Channel Patterns 5.5.2 Trace Metal Partitioning Mechanisms 5.5.3 Implications to Sampling 5.6 Physical and Mathematical Manipulations 5.7 Temporal Variations in Concentration 5.8 Summary 5.9 Suggested Readings 6 Floodplains 6.1 Introduction 6.2 Floodplains: Definition 6.3 The Formative Processes 6.4 Floodplain Sediments 6.4.1 Floodplain Deposits 6.5 Trace Metal Storage and Distribution 6.5.1 Grain Size Variations 6.5.2 Residence Time and Deposit Age 6.5.3 Sediment Mixing and Homogenization 6.5.4 Post-Depositional Processes 6.6 Overbank Sediments 6.6.1 Depositional Rates and Patterns 6.6.2 Geographical Patterns in Contaminant Concentrations 6.6.3 Documenting Pollution Histories 6.7 Sediment and Contaminant Source Determination 6.7.1 Non-point Source Multivariate Fingerprinting Methods 6.7.2 Isotopic Tracing Methods 6.8 Physical Remobilization 6.8.1 Bank Erosion Processes 6.9 Summary 6.10 Suggested Readings 7 River Metamorphosis 7.1 Introduction 7.2 The Balanced Condition 7.3 Thresholds, Complex Response, and Process Linkages 7.4 Adjustments in Channel Gradient, Shape, and Pattern 7.5 Effects of River Metamorphosis 7.6 Terraces 7.6.1 Definition and Formative Processes 7.6.2 Trace Metal Distributions 7.7 Quantifying Extent and Magnitude of Contamination 7.8 Summary 7.9 Suggested Readings 8 Remed