RESUMO

Model experiments carried out in mesocosms placed in the fish pond made it possible to simulate the peculiarities of methane formation at a high concentration of cadmium belonging to the most toxic heavy metals. The concentration of cadmium essentially exceeding its limiting permissible concentration results in the death of hydrobionts and in their gradual destruction and sedimentation to the bottom of mesocosms, which in its turn results in the decrease in the content of oxygen dissolved in the water, and also in the increase in the intensity of anaerobic processes, including methane genesis, both in the water and in bottom sediments.