My research interests include trace metal speciation and particularly Rare Earth Elements (REE), a better understanding of trace metal cycles in natural waters, and an improved knowledge of trace metals transport from rivers to ocean. The determination of inorganic and organic constituents and their impact on water quality requires an in-depth knowledge of the interactive water chemistry relationships. Chemical form and speciation play a significant role on the geochemical, toxicological, transport to the ocean and overall environmental impact on water quality. The development of analytical geochemistry technology to the solution of specific environmental problem requires extensive laboratory and field research and development effort. In this way, aqueous geochemical models have become popular tools for the interpretation of natural water geochemistry. Unfortunately, these models still show deficiencies, the major one being incorrect or inconsistent thermodynamic data. Objectives of my project are to develop, test, evaluate and make field applications of such geochemical models for equilibrium speciation of Rare Earth Elements from river to seawater.