1 part per million fluoride is:: (A) 1 mg in 10 L of water, (B) 1 mg in 1 L of water, (C) 10 mg in 1 L of water, (D) 100 mg in 10 L of water
Answer is B. ppm (or ppmm) is used to measure the concentration of a contaminant in soils and sediments. In that case, 1 ppm equals 1 mg of substance per liter of solid (mg/liter).