Research on the particle-mediated transport of “bound pollutants” tends to be conducted in the absence of a proper definition of particle and with a minimal consideration of colloidal phenomena. Recent developments in the use of transmission electron microscopy to monitor water fractionation schemes are providing a technology to correct this situation. This review summarizes the current status of the routine application of TEM in monitoring such schemes and in extending them into new areas of water research. It summarizes new findings on DOC relating to the extensive interpenetration of aggregated DOC “particles” with their aquatic milieu. Also, it relates colloidal phenomena to artifact generation in filter cascade schemes and in "particle-pollutant" interaction experiments. The usefulness of TEM in defining the ultrastructure of carbon-rich particulate materials and in elucidating colloid-particle interactions is demonstrated, as is the relevance of such measures to understanding pollutant dispersion.