Deuterium depleted water, sometimes called “light water”, is a water in which deuterium is found in a smaller concentration than in naturally occurring water.
Water with a deuterium molecule concentration of 1 to 120 parts per million can be considered deuterium depleted water or DDW, briefly. In average, deuterium is found in a concentration of 150 parts per million, in normal water. That is a rate of 1 deuterium atom for 6400 hydrogen atoms.
The deuterium content of waters in Europe is of 150 ppm (parts per million), with small fluctuations. The waters at the Equator have 155 ppm deuterium, while waters in northern Canada have 130-140 ppm deuterium. The deuterium quantity found in waters of a certain region is proportional to the deuterium concentration within the organisms living in that region.