What does testing for coliform primarily check for in water quality?

Testing for coliform primarily checks for potential fecal contamination in water sources. Coliform bacteria are a group of microorganisms typically found in the intestines of warm-blooded animals, including humans. Their presence in water is an indicator that fecal material may be present, which can lead to the introduction of harmful pathogens that are dangerous to human health.

When water testing reveals coliform bacteria, it raises concerns about the sanitation and safety of the water supply due to the possibility of contamination from sewage or animal waste. This specific monitoring is critical for ensuring that drinking water is safe and free from pathogens that can cause illness.

In contrast, the other options refer to different types of contaminants. Harmful microorganisms encompass a broader range of pathogens beyond coliforms, while chemical pollutants and physical contaminants pertain to non-biological issues in water quality. Thus, the focus of coliform testing directly aligns with concerns over potential fecal contamination rather than those other factors.