Turbidity is defined as what?

• A. The cloudiness or haziness of a fluid caused by suspended particles
• B. The color change due to chemical reaction
• C. The salinity of water
• D. The dissolved oxygen content

Answer: (A)

Turbidity describes how cloudy or hazy water is due to particles suspended in the liquid. This property is about light being scattered by those particles, not about color changes from chemical reactions, salt content, or the amount of dissolved oxygen. In practice, turbidity is often measured in nephelometric turbidity units (NTU) and is a key indicator of how much particulate matter is present, which affects treatment effectiveness and can signal potential microbial carryover or contamination. For example, runoff after a rainstorm can raise turbidity, making water appear murkier and potentially complicating disinfection and filtration.