Turbidity is caused by what kind of material in water?

Turbidity in water is primarily caused by suspended and colloidal materials. These materials include a wide range of particles such as silt, clay, organic matter, and microorganisms that are present in the water column but do not settle quickly to the bottom. The presence of these fine particles scatters light, making the water appear cloudy or turbid.

Dissolved minerals, although they can contribute to water quality, do not cause turbidity because they are below the detection limit of turbidity measurements and remain dissolved in water. Organic compounds may contribute to various water quality issues, but they do not inherently cause turbidity. Similarly, while bacteria contribute to the biological aspects of water quality and can affect turbidity when present in large numbers, they are just one type of suspended material among many that can cause turbidity. Therefore, the correct understanding of turbidity encompasses the presence of a variety of suspended and colloidal materials, leading to the choice being focused on those components specifically.