For these reasons we assume two distinctive scenarios: In the first, DDT formulation directly reaches the lake sediment, e.g., because of drift during application on fields and forests, or through intended dumping into the lake. In this scenario, mainly DDT is deposited and while minor parts may be transformed to DDE during deposition, most of the DDT is afterwards transformed to DDD anaerobically. In the second scenario, DDT reaches the sediment indirectly via erosion of topsoil some time after agricultural or forest application. The proportion of DDT in the eroded material will be higher at first, but with ongoing dwell time and, thus, transformation in the mostly aerobic soil, DDE concentrations will increase until they finally surpass those of DDT, if no additional DDT formulation is applied (lakes CR, OR, SL). Depending on the capacity of reservoirs capable of storing DDT surrounding the lakes, a more or less constant leakage input is imaginable, leading to steadily low concentrations in the profiles (Lake TF). Such a behavior of persistent chlorinated pollutants was observed in boreal forests of Norway by . In reality, these two scenarios will most probably occur coincidentally to different extents in different points of time.