To better understand the geochemical, biological, and toxicological impacts of sediment resuspension on lake ecosystems, this study focuses on questions where, why, when, how much, and what kind of sediment is resuspended and how the resuspended material is distributed in the water column. With data from a Sea Tech transmissometer and data from sediment traps it is shown that internal seiche activities are likely to be responsible for sediment resuspension in deeper areas of stratified lakes. Sediment traps were also used to develop a simple method which allows to quantify the proportion of resuspended settling particulate matter in lakes, and to distinguish organic resuspended settling particulate matter from newly produced planktonic settling particulate matter. In all 9 studied lakes, the dominant source of settling particulate matter was sediment resuspension, and in 4 of the 9 lakes sediment resuspension was even the dominant source of organic settling particulate matter.

Since settling particulate matter in the studied lakes usually consisted to a major part of resuspended particulate matter, even during phytoplankton blooms, the vertical distribution of resuspended and total settling particulate matter in the water column was similar during all seasons. Resuspended settling particulate matter was accumulated in hypolimnetic traps by a factor of up to 45 during the period of stratification (arithmetic mean: 9.5; median: 6.0). However, as soon as the period of stratification was over, resuspended settling particulate matter was almost evenly distributed in the water column. In contrast to this sedimentation pattern, the flux of newly produced planktonic settling particulate matter reaching the hypolimnion was not affected by stratification.

With the above knowledge and from a literature review, relationships between sediment resuspension and lake water pollution were compiled and discussed in connection with processes such as sorption and desorption, biouptake, and pollution dynamics - chronic versus pulse inputs.

Finally, a model was developed which can be used to determine (1) the minimum, mean and maximum flux of settling particulate matter in lakes, (2) daily variations in the flux, origin, and distribution of settling particulate matter both during stratification and mixing of the water column, (3) the boundary depth between accumulation and erosion/transportation bottoms, (4) the yearly sediment accumulation rates at different water depths, and (5) sediment focusing.