chapter  10
38 Pages

Biogeochemistry and Cycling of Lead

ByWilliam Shotyk and Gae¨l Le Roux

Institute of Environmental Geochemistry, University of Heidelberg, Im Neuenheimer Feld 236, D-69120 Heidelberg, Germany

1. Introduction 240

2. Chemistry of Lead and Behavior in the Environment 242

2.1. Summary of Basic Chemical Properties 242

2.2. Abundance and Occurrence 243

2.3. Measuring Lead Concentrations 244

3. Lead Isotopes and Their Measurement 245

3.1. Stable Isotopes 245

3.2. Measurements of Stable Lead Isotopes 246

3.3. Intermediate Decay Products of U-Th Decay Series 247

4. Ancient and Modern Uses of Lead 247

4.1. Ancient and Medieval Uses 247

4.2. Modern Uses 248

5. Emissions of Lead to the Environment 250

5.1. Lead in Natural vs. Anthropogenic Atmospheric Particles 251

5.2. Atmospheric Lead from Alkyllead Fuel Additives 251

6. Inputs and Fate of Anthropogenic Lead in the Biosphere 252

6.1. Lead Concentrations in Soils 252

6.2. Cumulative Impact of Anthropogenic, Atmospheric Lead 253

6.3. The Fate of Anthropogenic Lead in Soils 254

6.4. Lead Concentrations in Solution 255

7. Temporal Trends in Atmospheric Lead Deposition 255

7.1. Lead in Sediments 255

7.2. Lead in Bryophytes 256

7.3. Lead in Tree Rings and Bark Pockets 256

7.4. Peat Bog Archives 256

7.5. Relative Importance of Gasoline Lead vs. Other Sources

of Industrial Lead 257

7.6. The Cumulative Input of Anthropogenic Lead 257

7.7. Lead in Polar Snow and Ice 259

7.8. Lead in Atmospheric Aerosols Today 260

8. Environmental Lead Exposure and Human Health 263

8.1. Blood Lead Levels (BLLs) and Their Significance 263

8.2. Mechanism of Lead Poisoning 264

8.3. Predominant Sources of Lead Exposure 264

8.4. Other Sources of Lead Exposure 265

9. Summary and Conclusions 267

Acknowledgments 267

Abbreviations 268

References 268

1. INTRODUCTION

The environmental geochemistry of Pb has probably stimulated more scientific

interest than all other metallic elements combined. According to Jaworski [1],

“the local, regional, and global biogeochemical cycles of lead have been affected

by man to a greater degree than those of any other toxic element”. Why? The

main reasons are simple-lead is an extremely useful metal and is relatively

simple to work with. Because it melts at a relatively low temperature (3278C), however, it is easily emitted to the atmosphere during smelting and refining.

And because it has been used since Antiquity, environmental contamination by

Pb is probably as old as civilization itself.