ISBN: 354065755X
TITLE: Mercury in the Biogeochemical Cycle
AUTHOR: Lucotte, Marc; Schetagne, Roger; Therien, Normand; Langlois, Claude; Tremblay, Alain (Eds.)
TOC:

Rsum et synthse (French summary)1
1 Introduction 23
1.1 The Mercury Issue in Northern Qubec 23
1.2 Geographic Setting 24
1.2.1 Drainage Basin and Relief 24
1.2.2 Climate and Hydrology 25
1.2.3 Vegetation and Wildlife 26
1.2.4 Water Quality and Fish 26
1.2.5 Human Settlements 27
1.3 Hydroelectric Devlopments 27
1.3.1 Reservoirs 27
1.3.2 Other Modified Environments 31
1.4 Evolution of the Biophysical Environment 31
1.4.1 Water Quality 32
1.4.2 Plankton and Benthos 32
1.4.3 Fish 32
1.5 Contents and Rationale 35
2 Analysis of Total Mercury and Methylmercury In Environmental Samples 41
Abstract 41
2.1 Introduction 41
2.2 Total Mercury Measurements.42
2.2.1 Total Mercury by Cold Vapor Atomic Absorption Spectrophotometry 42
2.2.1.1 Organisms and Sediment Samples 42
2.2.1.2 Water Samples 43
2.2.2 Total Mercury by Atomic Fluorescence Spectrophotometry 44
2.2.2.1 Organisms and Sediment Samples 45
2.2.2.2 Water Samples 45
2.3 Methylmercury Measurements 48
2.3.1 Organisms and Sediment Samples 49
2.3.2 Water Samples 50
2.4 Conclusions 51
Acknowledgcmcnts 52
Mercury and Methylmercury in Natural Ecosystems of Northern Qubec
3 Mercury in Natural Lakes and Unperturbed Terrestrial Ecosystems of Northern Qubec 55
Abstract 55
3.1 Introduction 56
3.2 Materials and Methods 57
3.2.1 Aquatic Systems 57
3.2.2 Terrestrial Systems 58
3.2.3 Analyses 58
3.3 Results and Discussion 59
3.3.1 Mercury in Natural Lakes of Northern Qubec 59
3.3.1.1 Presence and Diagenesis of Mercury in Lake Sediments 59
3.3.1.2 Historic Interpretation of the Presence of Mercury in Sediments 61
3.3.1.3 Sedimentary Mercury and Terrigenous Organic Matter 62
3.3.1.4 Mercury in the Water Column of Natural Lakes
3.3.1.5 Mercury in Aquatic Macrophytes and in Riparian Plants 66
3.3.2 Mercury in Terrestrial Systems of Northern Quebec 67
3.3.2.1 Mercury in Terrestrial Vegetation of Northern Qubec 69
3.3.2.2 Distribution of Mercury in Forest Soils and Peatlands of the Boreal Domain 72
3.3.2.3 Anthropogenic Fraction of Mercury in Soils of Northern Qubec 77
3.3.3 Patterns of Atmospheric Mercury Deposition throughout Northern Qubec 81
3.4 Conclusions 85
Acknowledgements 86
4 Bioaccumulation of Mercury and Methylmercury in Invertebrates from Natural Boreal Lakes 89
Abstract 89
4.1 Introduction 89
4.2 Materials and Methods 90
4.2.1 Study Areas 90
4.2.2 Sampling 93
4.2.2.1 Insects 93
4.2.2.2 Plankton 93
4.2.3 Analyses 94
4.3 Results and Discussion 94
4.3.1 Total Mercury and Methylmercury Concentrations in Invertebrates 94
4.3.2 Bioavailability of Total Mercury and Methylmercury for Insect Larvae 101
4.3.3 Environmental Factors Influencing Mercury Bioavailbility 102
4.3.4 Biomagnification of Methylmercury along the Food Web 104
4.3.5 Diversity, Biomass and Mercury Burdens 109
4.4 Conclusions 112
Acknowledgements 112
5 Mercury in Fish of Natural Lakes of Northern Qubec 115
Abstract 115
5.1 Introduction 115
5.1.1 Study Area 116
5.2 Materials and Methods 120
5.3 Results 121
5.4 Discussion 125
5.5 Conclusions 129
Acknowledgements 130
6 Mercury in Birds and Mammals 131
Abstract 131
6.1 Introduction 131
6.2 Study Area 132
6.3 Materials and Methods 133
6.4 Results and Discussion 134
6.4.1 Mercury in Birds 134
6.4.2 Relationship with Geographical and Habitat Distribution 138
6.4.3 Diet Types 138
6.4.4 Eggs 140
6.4.5 Terrestrial Mammals 141
6.4.6 Marine Mammals 142
6.4.7 Freshwater Seals 143
6.5 Conclusions 144
Acknowledgements 144
Mercury Dynamics at the Flooded Soil-Water Interface in the Reservoirs
7 In Vitro Release of Mercury and Methylmercury
from Flooded Organic Matter 147
Abstract 147
7.1 Introduction 147
7.2 Materials and Methods 149
7.2.1 Sample Collection 149
7.2.2 Experimental Set up 149
7.2.3 Analytical Methods 151
7.2.3.1 Total Hg 151
7.2.3.2 MeHg 152
7.3 Results 152
7.4 Discussion 154
7.5 Conclusions 163
Acknowledgements 164
8 Mercury Dynamics at the Flooded Soil-Water Interface in Reservoirs of Northern Qubec: in Situ Observations 165
Abstract 165
8.1 Introduction 166
8.2 Materials and Methods 167
8.2.1 Study Sites 167
8.2.2 Sampling 167
8.2.3 Analyses 169
8.3 Results and Discussion 170
8.3.1 Temporal Evolution of Mercury in Flooded Soils 170
8.3.2 Mercury in the Water Column of Flooded Systems 176
8.3.2.1 Dissolved Fraction 176
8.3.2.2 Particulate Fraction 180
8.3.3 Influence of Flooded Soils on the Biogeochemical Cycle of Mercury in Reservoirs 183
8.3.3.1 Diffusion of Mercury from Flooded Soils 183
8.3.3.2 Burrowing Organisms and Erosion 184
8.3.3.3 Enhanced Biological Production and Methylation of Mercury 184
8.4 Conclusions 186
Acknowledgements 189
Evolution of Mercury Concentrations in Aquatic Organisms from Hydroelectric Reservoirs
9 Bioaccumulation of Methylmercury in Invertebrates from
Boreal Hydroelectric Reservoirs 193
Abstract 193
9.1 Introduction 193
9.2 Materials and Methods 194
9.2.1 Study Area 194
9.2.2 Sampling 194
9.2.2.1 Insects 194
9.2.2.2 Plankton 198
9.2.2.3 Flooded Soils and Lake Sediments 199
9.2.3 Analysis 199
9.3 Results and Discussion 199
9.3.1 Methylmercury Concentrations in Invertebrates 199
9.3.2 Biomagnification of Methylmercury Along the Invertebrate Food Chain 202
9.3.3 Bioavailability of Methylmercury to Insects 205
9.3.4 Bioavailability of Methylmercury to Plankton 208
9.3.5 Biomass and MeHg Burdens 210
9.4 Conclusions 213
Acknowledgements 214
10 Mercury Accumulation in Fish from the La Grande Complex: Influence of Feeding Habits and Concentrations of Mercury
in Ingested Prey 215
Abstract 215
10.1 Introduction 215
10.2 Materials and Methods 216
10.3 Results and Discussion 222
10.3.1 Non-Piscivorous Fish 222
10.3.2 Piscivorous Fish 227
10.4 Conclusions 232
Acknowledgements 233
11 Post-Impoundment Evolution of Fish Mercury Levels at the La Grande Complex, Qubec, Canada (from 1978 to 1996) 235
Abstract 235
11.1 Introduction 236
11.2 Materials and Methods 236
11.3 Results 238
11.3.1 Reservoirs 238
11.3.2 Dwarf Lake Whitefish 234
11.3.3 Rivers with Reduced Flow 234
11.3.4 Diversion Routes 234
11.3.5 Downstream from Reservoirs 245
11.3.5.1 The Caniapiscau River 245
11.3.5.2 The La Grande River 247
11.3.5.3 The Coast of James Bay 248
11.4 Discussion 249
11.4.1 Reservoirs 249
11.4.1.1 Increases of Fish Mercury Levels in Reservoirs 249
11.4.1.2 Factors Explaining Differences Observed Between Reservoirs 250
11.4.1.3 Duration of the Phenomenon in Reservoirs 254
11.4.2 Downstream from Reservoirs 257
11.4.3 Rivers with Reduced Flow 257
11.5 Conclusions 258 
Acknowledgements 258
12 Calculated Fluxes of Mercury to Fish in the Robert-Bourassa Reservoir 259
Abstract 259
12.1 Introduction 259
12.2 Materials and Methods 261
12.2.1 Estimation of Fish Standing Stocks 261
12.2.2 Estimation of Biomass Fluxes 261
12.2.3 Estimation of Hg Fluxes 263
12.2.4 Calculation of Hg Fluxes from Vegetation 264
12.2.5 Resolution of the Major Hg Fluxes 264
12.3 Results and Discussion 265
12.3.1 Biomass and Hg Fluxes 265
12.3.2 Fluxes of Hg from Vegetation 267
12.3.3 Resolution of the Major Mercury Fluxes 268
12.4 Conclusions 271
Acknowledgements 272
Mercury Toxicity for Wildlife Resources
13 Assessement of the Ecotoxic Risk of Methylmercury Exposure in Mink (Mustela vison) Inhabiting Northern Qubec 275 
Abstract 275 
13.1 Introduction 275 
13.2 Materials and Methods 276 
13.3 Results and Discussion 277 
13.3.1 In vitro Exposure to Methylmercury 277
13.3.2 Mercury Concentrations in Tissues Observed in the Wild  279
13.3.3 Ecological, Biological and Ethological Determinants 282
13.3.4 Risk to Wild Mink 283 
13.4 Conclusions 285 
Acknowledgements 285
14 Breeding Success of Osprey under High Seasonal
Methylmercury Exposure 287
Abstract 287
14.1 Introduction 287
14.2 Study Area and Methods 288
14.3 Results 289
14.4 Discussion 291
14.5 Conclusions 292
Acknowledgements 293
15 Synthesis 295
15.1 Mercury in Natural Ecosystems of Northern Qubec 295
15.1.1 Sources of Macury 295
15.1.2 Sediments and the Water Column 296
15.1.3 Invertebrates 296
15.1.4 Fish 297
15.1.5 Aquatic Birds 298
15.1.6 Mammals 298
15.2 The Mercury Issue at the La Grande Hydroelectric Development Complex 299
15.2.1 Methylation and Passive Transfer from the Flooded Soils and Vegetation to the Water Column 300
15.2.2 Mercury Increases in Organisms at the Base of the Aquatic Food Chain 302
15.2.3 Additional Active Transfer from the Flooded Soils to the Aquatic Food Chain 303
15.2.4 Mercury Increases in Fish 304 
15.2.4.1 Reservoirs 304
15.2.4.2 Downstream from Reservoirs 305 
15.2.5 Duration of Increased Mercury Levels in Fish 305
15.2.5.1 Degradation of Terrigenous Organic Matter and Release of Nutrients 306
15.2.5.2 Erosion 306 
15.2.5.3 Active Transfer from Burrowing Insects and Periphyton 307
15.2.6 Morphological and Hydrologic Factors Influencing the Evolution of Mercury Levels in Fish in Reservoirs 307
15.2.6.1 Land Area Flooded to Annual Volume of Water Ratio 308
15.2.6.2 Flooded Land Area in Drawdown Zone 308
15.2.6.3 Filling Time 309
15.2.7 Risk to Wildlife 309
15.2.7.1 Mink Experiment 309
15.2.7.2 Breeding Success of Osprey 310
16 Conclusion and Prospects 313 
16.1 Development of Models Predicting Fish Mercury Levels in Reservoirs 314 
16.2 Potential Mitigation Measures to Reduce the Temporary Increase in Fish Mercury Levels 315
16.3 Environmental Risk 316
References 317
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