What is included in the definition of total suspended solids (TSS)?

Total suspended solids (TSS) refers to the solid particles that are suspended in water and can include a wide range of materials, such as silt, sediment, organic matter, and other particulate substances that do not dissolve in water. The key aspect of TSS is that it specifically pertains to particles that remain in suspension, which can be quantified in various water samples, including effluent from treatment processes.

This is why the correct answer focuses on particles that remain in suspension in the effluent. These particles can impact water quality and are a significant consideration in environmental management, wastewater treatment, and pollution control.

Other options do not accurately reflect the definition of TSS. For instance, dissolved organic materials in water are not included in TSS, as TSS specifically pertains to suspended solids rather than dissolved substances. Settled sediments, while relevant to water quality, are not suspended and are therefore not part of TSS; they refer to materials that have already settled out of the water column. Lastly, while pesticides and chemicals may be present in water, they do not form the particulate matter that TSS measures, as they are also often dissolved in water rather than being solid components suspended in it.