Lecture
This lecture covers the concept of complexation in bio-geochemical systems, focusing on the speciation of metal ions and ligands in chemical equilibrium. It discusses examples of complexation in aqueous systems, mineral surfaces, and biological environments. The distribution of species and the importance of speciation in understanding toxicity, bioavailability, and mobility are highlighted. Various examples, such as copper complexation with carbonates and organic acids, are presented. The lecture also explores the role of complexation in soil, plants, and the human body, using selenium as a case study. It concludes by emphasizing the significance of species sensitivity in the transport, uptake, and toxicity of metal(loid) elements.