SUBMICRON PARTICLES IN THE RHINE RIVER .2. COMPARISON OF FIELD OBSERVATIONS AND MODEL PREDICTIONS

The particle size distribution in the Rhine River near Basle (Switzerl and) was measured for a period of over 1 year. Peaks in the measured s ize distributions were consistently observed in the ranges of 100-200, 300-700 nm and 1-3 mum. The size distributions observed did not vary greatly with time or flow rate. Predictions of a classical coagulation /sedimentation model agreed well with these field observations. This a greement between model predictions and field measurements indicated th at the unknown (and probably dynamic) ''initial'' particle distributio n may have been quickly transformed, either in the river or in the int erstitial soil solution, through coagulation and sedimentation into th e characteristic and relatively stable shape experimentally observed.