Which compound is commonly measured for its turbidity in water quality tests?

Turbidity in water quality tests is primarily measured due to the presence of suspended particles. These particles can include sediments, organic material, microorganisms, and other matter that can scatter and absorb light. When water contains a high concentration of suspended particles, it appears cloudy or murky, which indicates increased turbidity.

The measurement of turbidity is crucial because it can affect aquatic life, water treatment processes, and the efficacy of disinfection methods. High turbidity can also indicate potential contamination, making it an important parameter in assessing water quality.

In contrast, the other substances listed—such as calcium carbonate, silica, and fluoride ions—do not directly contribute to turbidity in the same way. Calcium carbonate and silica are more associated with hardness and mineral content, while fluoride ions relate to water fluoridation and dental health, rather than cloudiness or visibility of water. Thus, suspended particles are the most relevant indicator when discussing turbidity in water quality testing.