MELIMEX,an experimental heavy metal pollution study: Particle size distributions in limno-corrals

The particle size distributions in three limno-corrals, located in Baldeggersee, Switzerland, have been determined by means of a Zeiss Micro-Videomat image analyzer as a function of depth and time. The distributions were measured biweekly over a period of 1 year at depths of 0 m, 2.5 m, 5 m, 7.5 m and 10 m (=above bottom). Two of the limno-corrals were charged with heavy metals, whereas the third was uncharged and served as a reference. The shape of the distributions as well as the particle concentrations in the uncharged container did not differ from the ones in the charged limno-corrals. The distributions were found to be self-preserving and independent on heavy metal load, time, depth and particle concentrations. As an average, the dependence of the distributions on the particle diameter was found to be ?1.5 to ?2.5.