Preface ...................................................... xiii
1. Contaminated Rivers: An Overview ............................ l
1.1. Introduction .......................................... 1
1.2. Types of Contaminants ................................. 3
1.2.1. Organic Contaminants .......................... 3
1.2.2. Inorganic Contaminants ........................ 8
1.3. National Assessments of River Health ................. 11
1.3.1. The National Water Quality Inventory ......... 12
1.3.2. The National Sediment Quality Survey ......... 14
1.3.3. The National Water-Quality Assessment
Program ...................................... 17
1.3.4. Sources of Contamination ..................... 18
1.4. The Dissolved Versus Particulate Load ................ 21
1.5. Site Characterization, Assessment, and Remediation ... 23
1.6. The Geomorphological-Geochemical Approach ............ 27
1.7. Summary .............................................. 30
1.8. Suggested Readings ................................... 31
2. Sediment-Trace Metal Interactions .......................... 33
2.1. Introduction ......................................... 33
2.2. Physical Partitioning of Trace Metals in Sediment .... 34
2.3. Chemical Partitioning of Trace Elements in
Sediment ............................................. 39
2.3.1. Mechanistic Associations ..................... 39
2.3.2. Chemically Reactive Substrates ............... 53
2.4. Elemental Speciation ................................. 60
2.5. Chemical Remobilization .............................. 63
2.6. Summary .............................................. 66
2.7. Suggested Readings ................................... 67
3. Basin Processes ............................................ 69
3.1. Introduction ......................................... 69
3.2. Hillslope Hydrology .................................. 70
3.2.1. Direct Runoff Generation ..................... 70
3.2.2. Flood Hydrographs ............................ 76
3.3. Contaminant Transport Pathways ....................... 80
3.3.1. The Controlling Factors ...................... 80
3.3.2. Transport via Hortonian Overland Flow ........ 84
3.3.3. Mapping Spatial Variations in Metal
Sources ...................................... 85
3.4. Hillslope Erosion .................................... 88
3.4.1. Basic Mechanics .............................. 88
3.4.2. Measurement of Erosion Rates ................. 89
3.4.3. Prediction of Erosion Rates .................. 91
3.5. Summary ............................................. 101
3.6. Suggested Readings .................................. 102
4. The Water Column - Concentration and Load ................. 103
4.1. Introduction ........................................ 103
4.2. Temporal Variations in Concentration ................ 104
4.2.1. Dissolved Constituents ...................... 104
4.2.2. Particulate and Particulate-Borne
Contaminant Concentrations .................. 113
4.3. Sediment and Contaminant Loads ...................... 118
4.3.1. Load Estimation ............................. 118
4.3.2. The Effective Transporting Discharge ........ 123
4.4. Summary ............................................. 125
4.5. Suggested Readings .................................. 126
5. The Channel Bed - Contaminant Transport and
Storage ................................................... 127
5.1. Introduction ........................................ 127
5.2. Sediment Transport .................................. 128
5.2.1. Modes of Transport .......................... 128
5.2.2. Channelized Flow ............................ 129
5.2.3. Entrainment ................................. 132
5.3. Processes of Contaminant Dispersal .................. 136
5.3.1. Hydraulic Sorting ........................... 136
5.3.2. Dilution and Exchange with the Floodplain ... 138
5.3.3. Sediment Storage and Exchange Mechanisms .... 140
5.3.4. Geochemical Processes and Biological
Uptake ...................................... 142
5.4. Downstream Patterns ................................. 144
5.4.1. Impoundment Failures ...................... 148
5.5. Deposition and Storage along a Reach ................ 151
5.5.1. Channel Patterns ............................ 152
5.5.2. Trace Metal Partitioning Mechanisms ......... 162
5.5.3. Implications to Sampling .................... 168
5.6. Physical and Mathematical Manipulations ............. 170
5.7. Temporal Variations in Concentration ................ 173
5.8. Summary ............................................. 175
5.9. Suggested Readings .................................. 176
6. Floodplains ............................................... 177
6.1. Introduction ........................................ 177
6.2. Floodplains: Definition ............................. 178
6.3. The Formative Processes ............................. 180
6.4. Floodplain Sediments ................................ 185
6.4.1. Floodplain Deposits ......................... 187
6.5. Trace Metal Storage and Distribution ................ 193
6.5.1. Grain Size Variations ....................... 196
6.5.2. Residence Time and Deposit Age .............. 198
6.5.3. Sediment Mixing and Homogenization .......... 200
6.5.4. Post-Depositional Processes ................. 200
6.6. Overbank Sediments .................................. 202
6.6.1. Depositional Rates and Patterns ............. 203
6.6.2. Geographical Patterns in Contaminant
Concentrations .............................. 209
6.6.3. Documenting Pollution Histories ............. 214
6.7. Sediment and Contaminant Source Determination ....... 219
6.7.1. Non-point Source Multivariate
Fingerprinting Methods ...................... 220
6.7.2. Isotopic Tracing Methods .................... 222
6.8. Physical Remobilization ............................. 227
6.8.1. Bank Erosion Processes ...................... 228
6.9. Summary ............................................. 232
6.10. Suggested Readings .................................. 234
7. River Metamorphosis ....................................... 235
7.1. Introduction ........................................ 235
7.2. The Balanced Condition .............................. 235
7.3. Thresholds, Complex Response, and Process
Linkages ............................................ 241
7.4. Adjustments in Channel Gradient, Shape, and
Pattern ............................................. 248
7.5. Effects of River Metamorphosis ...................... 252
7.6. Terraces ............................................ 254
7.6.1. Definition and Formative Processes .......... 254
7.6.2. Trace Metal Distributions ................... 258
7.7. Quantifying Extent and Magnitude of Contamination ... 262
7.8. Summary ............................................. 269
7.9. Suggested Readings .................................. 270
8. Remediation and Remediation Standards ..................... 271
8.1. Introduction ........................................ 271
8.2. Setting Remediation Standards ....................... 273
8.2.1. Background Concentrations ................... 276
8.2.2. Health and Risk Based Standards ............. 282
8.3. Prioritizing Cleanup ................................ 285
8.4. Summary ............................................. 287
8.5. Suggested Readings .................................. 288
9. Ex Situ Remediation and Channel Restoration ............... 289
9.1. Introduction ........................................ 289
9.2. Ex Situ Remediation Techniques ...................... 291
9.2.1. Excavation .................................. 292
9.2.2. Dredging .................................... 294
9.3. Ex Situ Treatments .................................. 302
9.3.1. Dewatering and Particle Separation .......... 303
9.3.2. Soil Washing ................................ 305
9.3.3. Other Treatment Alternatives ................ 308
9.4. River Restoration and Rehabilitation ................ 310
9.4.1. Goals and Objectives ........................ 310
9.4.2. Channel Reconstruction ...................... 313
9.4.3. In-stream Structures, Bank Protection,
and Habitat Formation ....................... 317
9.5. Summary ............................................. 324
9.6. Suggested Readings .................................. 325
10. In Situ Remediation ....................................... 327
10.1. Introduction ........................................ 327
10.2. In Situ Extraction .................................. 328
10.2.1. Soil Flushing ............................... 328
10.2.2. Electrokinetic Separation ................... 330
10.2.3. Phytoremediation ............................ 334
10.3. In Situ Containment ................................. 338
10.3.1. In Situ (Subaqueous) Capping ................ 338
10.3.2. Soil and Sediment Capping ................... 341
10.3.3. In Situ Solidification and Stabilization .... 342
10.3.4. Phytostabilization and Immobilization ....... 343
10.4. Monitored Natural Recovery .......................... 346
10.5. Summary ............................................. 350
10.6. Suggested Readings .................................. 350
Appendix A. Dating Techniques ................................. 351
A.1. Introduction ........................................ 351
A.2. Short-Lived Radionuclides (Pb-210 and Cs-137) ....... 352
A.3. Radiocarbon (C-14) .................................. 357
A.4. Luminescence Techniques (TL, IRSL, and OSL) ......... 358
A.5. Marker Beds (Tephra, Trace Metals) .................. 359
A.6. Dendrochronology .................................... 361
Appendix B. Unit Conversions and Elemental Data ............... 365
References .................................................... 369
Glossary ...................................................... 399
Credits ....................................................... 405
Index ......................................................... 413
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