For the municipality of the same name in Gloucester County, see Monroe Township, Gloucester County, New Jersey.
How to measure dissolved oxygen. Dissolved oxygen is measured using a dissolved oxygen meter. The best method is to take the measurement in the field at the same time each day because DO concentrations can vary throughout a 24 hour period.issolved oxygen (DO) is a measure of the quantity of free oxygen molecules in water.
Dissolved oxygen is measured in milligrams per liter (mg/L). One milligram (mg) is 1/1000 (one thousandth) of a gram or 1/1000000 (one millionth) of a kilogram. 1 kilogram of water weighs 1 kilogram and occupies a volume of 1 liter (L).Therefore, expressing dissolved oxygen in mg/L is the same as using units of parts per million (ppm).Twelve parts per million (12 mg/L) is the highest amount of oxygen that can be dissolved in water under standard barometric pressures (sea level); 12 mg/L is known as the saturation point.Zero parts per million (0 mg/L) is the lowest amount of dissolved oxygen in water.ince, the amount of oxygen dissolved in water is small compared to the weight of water, it isn't appropriate to describe the level of dissolved oxygen in terms of a percentage.