1) Substantial quantities of water polluting mineral oil components find their way into the sediments of surface waters. Hydrocarbons settle if they get attached to settling particulate material (biological debris, clays, CaCO3, metal oxides, etc.) by adsorption and by agglomeration (coagulation) of colloidal droplets with suspended matter. 2) Formation of dispersed oil droplets from an oil film or oil layer depends strongly on the water turbulence (velocity gradient) and on the interfacial tension of the oil-water interface which in turn is affected by surfactants (emulsifiers) incipiently present in the oil. 3) Agglomeration of oil droplets with other suspended solids typically present in the water is a prerequisite for substantial oil sedimentation. A simple model based on surface charge densities and mass densities of the hetero-colloids coagulating predicts the conditions under which dispersed oil becomes agglomerated and evaluates whether the agglomerates formed will settle or rise.