Trace metals in seawater occur in many different chemical and physical forms, or species. The bioavailability and toxicity of metals depends on the speciation, and several studies have shown that most organisms are sensitive only to some subfraction of dissolved metals. For this reason, it is important to know how metals partition between particles and solution, in order to better understand the potential impact on aquatic organisms. This report summarizes measurements conducted during the past year of trace metal concentrations and partitioning in the waters of six Texas estuaries.