ppm

Parts per million (= mg/kg).

Standardized measurement used to describe the level of fluoride in products that contain it (e.g., toothpaste, mouthrinse, and water).

Abbreviation for parts per million; a weight-for-weight (w/w) concentration equal to 1 mg/kg or 1 g/tonne. Used most commonly to express the concentration of toxicants or trace elements in water, feeds, solvents and tissues.