What is equivalent to 5 milligrams per liter?

• A. 5 parts per billion
• B. 5 parts per million
• C. 5 percent concentration
• D. 5 grams per liter

Answer: (B)

5 milligrams per liter is equivalent to 5 parts per million (ppm) because both units express the same concentration of a substance in a solution. In the context of water treatment and environmental monitoring, 1 milligram per liter is defined as 1 part per million, since 1 liter of water weighs approximately 1,000 grams. Therefore, when considering a concentration of 5 milligrams in a liter of water, it translates directly to 5 parts per million.

Understanding this relationship is crucial in wastewater management and environmental science, as it allows professionals to accurately assess pollutant levels and their potential impact on water quality.