The major advances in knowledge of the concentrations and distributions of trace metals in the seas and oceans have occurred since the mid 1970s. This progress reflects major breakthroughs in procedures for essentially contamination-free (clean) sampling, the adoption of clean methodologies for handling and analysis of samples, and improvements in the analytical methods themselves. The extent of progress by the early 1980s was demonstrated by the major collection of papers edited by Wong et al. 1 Overviews of the subject have been given by Burton and Statham 2 and Bruland. 3 With the improved knowledge of the true variations in the concentrations of metals within the ocean, many systematic features in their distributions have become apparent. It has been possible to classify their marine geochemical behaviors and to interpret these in terms of the interactions of the dissolved chemical species with particulate material, which reflect the fundamental bonding properties of the elements. 4