Part I. Sampling and Characterization of Atmospheric Particles. 1. Source Apportionment of Atmospheric Particles. 2. Acid-Base Equilibria of Aerosols and Gases in the Atmosphere. 3. Characterization of Individual Environmental Particles by Beam Techniques. 4. Characterization of the Cr(VI)/Cr(III) Ratio in Aerosols. Part II. Sampling and Characterization of Particles of Aquatic Systems. 5. The Use of Filtration and Ultrafiltration for Size Fractionation of Aquatic Particles, Colloids, and Macromolecules. 6. Evaluation of Electron Microscopic Techniques for the Description of Aquatic Colloids. 7. Characterization of Particle Surface Charge. 8. Iron Particles in Freshwater. 9. Characterization of Oceanic Biogenic Particles. Part III. Reaction and Transport of Particles in Aquatic Systems. 10. The Role of Particles and Colloids in the Transport of Radionuclides and Trace Metals in the Oceans. 11. Sorption of Trace Elements on Natural Particles on Oxic Environments. 12. Ion Binding by Natural Heterogenous Particles. 13. Dynamic Aspects of Metal Speciation in Aquatic Colloidal Systems. Index.