To elucidate the actual state of cadmium pollution, we should solve some problems in advance, such as the analytical method that will enable us to measure the background contents of cadmium in surface waters, the concentration mechanism of zinc and cadmium in the soil of paddy field, and the physiological behaviour of cadmium in Graminae or especially in Oryza sative L.. Material balance-sheet may be applied to the area in question, to find a clue to pollution problems not only of cadmium but also of other materials. In some cases, it takes time for polluting material to accumulate, as has been revealed with the accumulation of strontium 90 after experiments of nuclear bombs in the stratosphere. In such cases, the accumulation will be still increased after the cessation of the cause of pollution. The increase of carbon dioxide contents in the atmosphere, though it has only a potential harm at present, brings out another question. Is it possible for mankind to stop the use of fossil fuels, the cause of the carbon dioxide increase? From the geoscientific point of view, those pollution problems occupy but a small part of the results from spoiling the harmony of nature by mankind. In soils of cultivated area, natural harmony of material balance has been destroyed, but still there is some possibility to recover it. As to the mineral resources, we have excavated so much metals and fossil fuels that it is impossible for us to recover the natural balance with them. We schould establish a new harmony which is not natural but fully controlled by us, and that will contribute to the eradication of pollution problems. Some ideas concerning the foundation of man-controlled harmony are presented.