Geochemistry of platinum group elements in the ocean

The review considers the current state of research on the geochemistry of platinum group elements (PGEs) in the ocean. The behavior of PGE in the aquatic environment is determined by their degree of oxidation, the ability to change it, and complexation. The difference in chemical properties of PGEs leads to the fact that in the ocean they do not retain group behavior and fractionate significantly. This is their characteristic feature, along with their ultra-low contents. The paper describes the sources of PGEs entering the ocean, their behavior in the river-sea mixing zone, and their distribution in seawater. The processes of PGE accumulation in sediments, sulfide and ferromanganese sediments of the ocean are considered. Possible mechanisms of PGE accumulation on ferromanganese oxyhydroxides are discussed.