Characteristics of Bottom Sediments in Polish Lakes with Different Trophic Status

An analysis of the chemical parameters of bottom sediments in selected Polish lakes was made, based on historical and recent data demonstrating the chemical composition of profundal sediments. The analysed lakes belong to a broad environmental spectrum, being different in the hydrological regime (seepage, flow-through), trophic state (mesotrophic, eutrophic, dystrophic), mixing type (polymictic, holomictic, meromictic), stratification (stratified, non-stratified) and sewage input presence (in the past or now). Moreover, some have been restored using technical methods (artificial mixing with and without destratification, phosphorus inactivation).