Turbidity, measured as NTU or FNU

Overview

Turbidity is a water-quality term that refers to the cloudy appearance of water and is caused by small particles of suspended matter. Turbidity is measured by quantifying the amount of light scattered by particles in the water. Although turbid water is not necessarily harmful, it can be an indicator of more serious problems. Turbidity particles may adsorb other harmful contaminants. Turbidity particles known to be harmful themselves include asbestos, lead, bacteria and viruses, and protozoan cysts such as Giardia and Cryptosiporidium.