Preface ....................................................... iii
Executive Summary ............................................... 1
Extended Summary ................................................ 7
Motivation for this Report ................................... 7
Scope of the Report .......................................... 8
Properties and Sources of Cesium-137 ........................ 11
Cesium-137 Contamination at Three DOE Sites in the United
States ...................................................... 13
Savannah River Site ...................................... 13
Oak Ridge Reservation .................................... 15
Hanford Site ............................................. 17
Behavior of Cesium-137 in Terrestrial Ecosystems ............ 19
Behavior of Cesium-137 in Aquatic Ecosystems ................ 24
Managing Contaminated Ecosystems ............................ 30
1 Introduction ................................................ 38
2 Properties of Cesium Isotopes ............................... 45
2.1 Physical, Chemical and Biological Properties of
Cesium Isotopes ........................................ 45
2.2 Processes Affecting General Distribution Patterns
of Radiocesium ......................................... 48
3 Radiocesium in the Global Environment ....................... 51
3.1 Sources of Radiocesium in the Environment .............. 51
3.1.1 Nuclear Weapon Detonations ...................... 51
3.1.1.1 Atmospheric Testing ......................... 51
3.1.1.2 Underground Testing ......................... 53
3.1.1.3 Shallow Underground Testing ................. 54
3.1.2 Fuel Reprocessing and Waste Disposal ............ 54
3.1.3 Reactor Releases ................................ 57
3.1.3.1 Releases During Routine Operations ......... 57
3.1.3.2 Reactor Accidents: Emphasis on Chernobyl ... 58
3.1.4 Releases from Medical Uses of Cesium-137 ........ 65
3.2 Geographic Distribution Patterns of Cesium-137
Deposition ............................................. 65
4 Primary Sites of Local Cesium-137 Contamination in the
United States ............................................... 70
4.1 Savannah River Site .................................... 70
4.1.1 Climate and Setting ............................. 72
4.1.2 Sources of Radiocesium .......................... 73
4.1.3 Release History ................................. 74
4.1.4 Environments .................................... 75
4.1.4.1 Aquatic Environments ........................ 77
4.1.4.1.1 Water: Levels and Trends ................ 78
4.1.4.1.2 Sediment: Levels and Trends ............. 81
4.1.4.1.3 Biota: Levels and Trends ................ 85
4.1.4.2 Terrestrial Environments .................... 89
4.1.4.2.1 Soils: Levels and Trends ................ 90
4.1.4.2.2 Biota: Levels and Trends ................ 91
4.1.5 Unique Pathways, Parameters and Conditions ...... 94
4.1.6 Future Management Issues ........................ 94
4.2 Oak Ridge Reservation .................................. 95
4.2.1 Climate and Setting ............................. 96
4.2.2 Sources of Cesium-137 ........................... 98
4.2.3 Release History ................................ 100
4.2.4 Aquatic Environments ........................... 100
4.2.4.1 Retention Ponds and Settling Basins ........ 100
4.2.4.2 White Oak Creek Watershed and Melton
Valley ..................................... 101
4.2.4.3 White Oak Lake ............................. 102
4.2.4.4 Clinch River ............................... 103
4.2.4.5 Levels and Trends of Cesium-137 in
Aquatic Systems ............................ 105
4.2.4.5.1 Water .................................. 105
4.2.4.5.2 Sediments .............................. 106
4.2.4.5.3 Aquatic Biota .......................... 108
4.2.5 Terrestrial Environments ....................... 109
4.2.5.1 Experimental Sites ......................... 109
4.2.5.2 White Oak Creek Floodplain ................. 112
4.2.5.3 White 0ak Lake Bed ......................... 112
4.2.5.4 Levels and Trends of Cesium-137 in
Terrestrial Systems ........................ 112
4.2.5.4.1 Accumulation in Plants ................. 112
4.2.5.4.2 Accumulation in Animals ................ 113
4.2.6 Unique Pathways, Parameters and Conditions ..... 118
4.2.7 Future Management Issues ....................... 118
4.3 Hanford Site ......................................... 120
4.3.1 Climate and Setting ............................ 120
4.3.2 Sources of Cesium-137 .......................... 123
4.3.3 Release History ................................ 125
4.3.4 Environments ................................... 126
4.3.4.1 Aquatic Environments ....................... 126
4.3.4.1.1 Water: Levels and Trends ............... 128
4.3.4.1.2 Sediment: Levels and Trends ............ 129
4.3.4.1.3 Biota: Levels and Trends ............... 130
4.3.4.2 Terrestrial Environments ................... 132
4.3.4.2.1 Soils: Levels and Trends ............... 134
4.3.4.2.2 Biota: Levels and Trends ............... 135
4.3.5 Unique Pathways, Parameters and Conditions ..... 137
4.3.6 Future Management Issues ....................... 139
5 Behavior and Transport in Terrestrial Ecosystems ........... 141
5.1 Chemistry and Sorption Properties of Cesium ........... 142
5.1.1 Chemistry and Speciation ....................... 142
5.1.2 Influence of Mineralogy on Sorption of Cesium .. 143
5.1.3 Soil/Sediment Partition Coefficient Values
for Cesium ..................................... 150
5.2 Biogeochemical Transport Processes for Cesium ......... 156
5.2.1 Deposition from the Atmosphere ................. 157
5.2.1.1 Dry Deposition ............................. 159
5.2.1.2 Wet Deposition ............................. 162
5.2.1.3 Combined Deposition ........................ 163
5.2.2 Weathering from Plant Surfaces ................. 164
5.2.3 Foliar Absorption .............................. 166
5.2.4 Soil Processes ................................. 168
5.2.5 Soil-to-Plant Transfer ......................... 176
5.2.5.1 Concentration Ratios ....................... 177
5.2.5.2 Regression Approaches ...................... 185
5.2.5.3 Temporal Trends in Plant Uptake ............ 188
5.2.5.4 Nutritional Uptake Models .................. 191
5.2.5.5 Resuspension and Soil Loading .............. 192
5.2.6 Translocation within Plants .................... 195
5.2.7 Microbial Impacts on Cesium Mobility ........... 206
5.2.8 Plant-to-Animal Transfers ...................... 208
5.2.9 Soil-to-Animal Transfers ....................... 212
5.2.10 Transfers in Animal Food Chains ................ 212
5.2.11 Assimilation and Retention in Animals .......... 214
5.3 Modeling Approaches for Radiocesium in Terrestrial
Ecosystems ............................................ 217
5.3.1 General Approaches ............................. 217
5.3.2 Model Validation ............................... 222
5.3.3 Uncertainty and Sensitivity Analyses ........... 224
6 Behavior and Transport in Freshwater Ecosystems ............ 228
6.1 Sediment-Water Partitioning of Cesium-137 ............. 229
6.1.1 Partition Coefficient .......................... 229
6.1.1.1 Particle Size .............................. 230
6.1.1.2 Particle Composition ....................... 230
6.1.1.3 Water Chemistry ............................ 231
6.1.1.4 Sorption Kinetics .......................... 231
6.1.1.5 Relative Abundances of Solution and Solid
Phases ..................................... 232
6.1.2 Settling and Sedimentation ..................... 232
6.1.3 Remobilization ................................. 233
6.1.4 Burial ......................................... 233
6.2 Modeling Sediment/Water Processes for Cesium-137 ...... 234
6.3 Bioaccumulation of Cesium-137 in Aquatic Food Webs .... 235
6.3.1 Uptake of Cesium-137 by Aquatic Organisms ...... 235
6.3.1.1 Direct Uptake from Water ................... 235
6.3.1.2 Uptake Through Ingestion of Food ........... 237
6.3.2 Elimination of Cesium-137 by Aquatic
Organisms ...................................... 238
6.3.2.1 Elimination of Cesium-137 by Aquatic
Primary Producers .......................... 238
6.3.2.2 Elimination of Cesium-137 by Aquatic
Invertebrates .............................. 239
6.3.2.3 Elimination of Cesium-137 by Fish .......... 239
6.4 Modeling the Bioaccumulation of Cesium-137 in
Aquatic Food Webs ..................................... 242
6.4.1 Concentration Ratio Models ..................... 242
6.4.1.1 Physicochemical and Trophic Factors ........ 243
6.4.1.2 Biomagnification ........................... 245
6.4.2 Hybrid Models .................................. 248
6.4.3 Dynamic Models ................................. 248
6.4.3.1 Cesium Mass Balance Models for Fish ........ 249
6.4.3.2 Implications of Seasonality ................ 252
6.5 Towards Whole Ecosystem Modeling ...................... 255
7 Managing Contaminated Ecosystems ........................... 256
7.1 The No-Action Alternative ............................. 257
7.2 Remediation Techniques ................................ 259
7.2.1 Biological Remediation ......................... 259
7.2.1.1 Microbiological Effects .................... 260
7.2.1.2 Phytoextraction ............................ 260
7.2.1.3 Phytostabilization ......................... 264
7.2.2 Chemical Remediation ........................... 265
7.2.3 Physical Remediation ........................... 266
7.3 Countermeasures Based on the Chernobyl Experience ..... 269
7.3.1 Relocation of People from the Most Heavily
Contaminated Areas ............................. 270
7.3.2 Limiting Consumption of Contaminated Food ...... 270
7.3.3 Agricultural Countermeasures ................... 271
7.3.4 Urban Countermeasures .......................... 274
7.3.5 Aquatic Countermeasures ........................ 275
7.3.5.1 Cesium-137 Contamination of the Pripyat-
Dnieper River System ....................... 275
7.3.5.2 Transport from Terrestrial Ecosystems to
Surface Waters ............................. 276
7.3.5.3 Engineering and Remediation Measures in
Aquatic Systems ............................ 278
7.4 Benefit-Cost Analyses ................................. 280
Glossary ...................................................... 283
Abbreviations, Acronyms and Symbols ........................... 301
References .................................................... 302
The NCRP ...................................................... 354
NCRP Publications ............................................. 364
Index ......................................................... 374
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