If coliform bacteria are present in the water supply, which of the following may also be present?

The presence of coliform bacteria in a water supply indicates potential contamination, which could also include pathogens. Coliform bacteria, particularly fecal coliforms, serve as indicators of water quality and the possible presence of other harmful microorganisms, such as viruses, parasites, and bacteria that can cause diseases. This is because coliforms are often found in the intestines of warm-blooded animals and can enter the water supply through fecal contamination.

When coliform bacteria are detected, it is essential to consider that the same sources contributing to their presence—like sewage or runoff from agricultural areas—may also introduce pathogens into the water supply. Testing for coliforms is a primary means of monitoring microbial water quality, particularly in drinking water systems.

In contrast, while harmful chemicals, heavy metals, and radioactive substances may also contaminate water supplies, their presence is not inherently linked to the presence of coliform bacteria in the same way that pathogens are. These contaminants generally originate from different sources, such as industrial discharges, mining activities, or agricultural runoff, rather than from biological contamination. Therefore, the likelihood of pathogens being present alongside coliform bacteria identifies a specific concern regarding the safety of the water for human consumption.