Question: how much oxygen is in 1 liter of water?
Answer: 4.2 Solubility of oxygen As indicated earlier, the atmospheric air has 20.9% (209 ml/1) of oxygen. Relatively the amount (volume) of DO in water is much less, 5.3 ml in a litre of air-saturated water at 30°C i.e. about 0.5% - by weight the proportion is still less - 7.6 mg in a litre or kg of water (see Fig. 2).