How is concentration in a solution often quantified in water quality?

Concentration in a solution, especially in the context of water quality, is most commonly quantified in parts per million (ppm). This unit represents the mass of a solute in a given mass of solution and is particularly useful for expressing very dilute solutions. For instance, one part per million indicates one milligram of a substance in one liter of water, making it easy to understand and compare the amount of contaminants or nutrients in water samples.

This measurement is crucial in water quality assessments because many pollutants or substances of interest, such as heavy metals, nutrients, or microorganisms, often exist in very low concentrations. Using ppm allows professionals and researchers to convey these small quantities effectively and ensures they can monitor and regulate water quality to safeguard public health and the environment.