PPM and PPB are abbreviations used in the field of chemistry and environmental science to measure the concentration of substances in water and other solutions. PPM stands for parts per million and PPB stands for parts per billion, and they represent the ratio of the amount of one substance (the solute) to the amount of the entire solutions (including the solvent) in terms of either millionths or billionths. As an example, PPM is a unit of concentration where the amount of the solute is expressed as a proportion of one million parts of the solution and often used when the concentration of a substance is relatively high. 1 PPM is equivalent to 1 milligram of solute per litre of solution (mg/L), for example, if you have 100mg of salt dissolved in 100,000mL (100L) of water, the concentration of salt is 1,000 parts per million (PPM). As for parts per billion, PBB is a unit of concentration where the mount of the solute is expressed as a proportion of one billion parts of the solution which is used when the concentration of a substance is very low or when high precision if required. 1 PPB is equivalent to 1 microgram of solute per litre of solution (µg/L), for example, if you have 1 µg of contaminant in 1,000,000 mL (1,000L) of ground water, the concentration of the contaminant if 1 PPB.
PPM and PPB are both valuable units for being able to measure the concentration of various substances in water, such as pollutants, minerals, chemical and contaminants. They are regularly and commonly used in water quality testing, environmental monitoring, and regulatory standards to ensure that water meets specific quality and safety criteria.