Which of the following is a physical contaminant in drinking water?

In the context of drinking water contaminants, physical contaminants refer to substances that can be sensed or measured in a physical manner, such as through appearance or physical state. In this question, coliform bacteria are often categorized under biological contaminants rather than physical.

When identifying a physical contaminant, one looks for materials that are typically solid or particulate in nature, which can include sediment, sand, or other suspended materials that physically alter the appearance or clarity of water. Heavy metals might seem to fit as a physical form, but they are generally classified under chemical contaminants rather than physical because they originate from chemical sources.

Viruses are biological entities and fall into the category of biological contaminants as they require a host to survive and cannot be measured physically in the same way. Chlorine, while a chemical used for disinfection, is typically not classified as a physical contaminant either.

This classification helps to understand the range of possible contaminants in drinking water and informs the methods used for detection and treatment of each type, ensuring safe drinking water for communities.