Ala Lombolo
- One of Sweden's most polluted lakes

Since pollutants tend to bind to small fractions and organic content it is likely to find them in large concentrations in calm aquatic environments where smaller grains can settle. If the energy in the water is too high for the settling of these particles the polluted sediments will be transported with the water and settle in a more quiet environment. The energy levels of water bodies can change with the seasons, resulting in the spreading of polluted sediments during some periods of the year while there will be no spreading during other parts of the year. The realation between sedimentation or erosion of grains and the flow velocity of e.g a river is shown in a so called "Hjulström diagram" which is shown below.

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As mentioned in the section 'Ala Lombolo', sub-heading 'The pollution', the bottom environment in Ala Lombolo is calm enough for fine material to settle, except for during periods of extreme flow or storm conditions. Upstream from Ala Lombolo, the smaller lake Yli Lombolo is seated, which surprisingly exhibits lower concentrations of pollutants. The reason is Yli Lombolo's shallow nature, which in combination with the flow velocity creates an erosion/transport bottom environment, preventing finer grains to settle and instead beeing transported with the stream to Ala Lombolo where the conditions favour sedimentation.