What is the primary role of colliform bacteria in water quality testing?

The primary role of coliform bacteria in water quality testing is to serve as indicators of fecal contamination. Coliforms are a group of bacteria, which include both harmful and harmless species, and their presence in water typically suggests that there may be contamination by fecal matter, which could harbor pathogens harmful to human health. Testing for coliform bacteria is a common practice in assessing the microbiological quality of water sources, such as drinking water or recreational waters.

When coliform bacteria are detected, it prompts further investigation to identify potential sources of contamination and to assess the risk of waterborne diseases. The presence of these bacteria serves as a red flag for water safety, indicating that a more comprehensive analysis may be needed to ensure that the water is clean and safe to consume.

The other options do not align with the primary role of coliform bacteria. They do not indicate pesticides, do not measure water pH levels, and do not detect heavy metals. Each of these functions requires different testing methods and indicators.