PPM stand for Parts-per-million,it is the measurement of chemical, or contaminated mass in unit per volume of water.PPM can also be expressed as m/L ( milligrams per Liter).Compared to Parts-per-Billion is it used for the same purpose but in different measurement.Parts-per-Billion is the “weight to weight ratio used to describe concentrations of contaminants.Parts per billion is the ccnumber of units of mass of a contaminant per 1000 million units of total mass also know as µg/L, or micrograms per liter”(GreenFacts).”These measurements refer to exposure standards, and guidelines created to protect the public from harmful substances that can cause serious health effects. Exposure standards and guidelines are created from risk assessments that
