What do fecal coliform bacteria suggest about water quality?

Fecal coliform bacteria are used as indicators of water quality primarily because their presence suggests that the water has been contaminated by fecal material, typically from warm-blooded animals, including humans. This contamination is an important indicator of potential sewage contamination and the presence of pathogens that can cause waterborne diseases.

When fecal coliform bacteria are detected in a water sample, it raises concerns about the safety of that water for human use, particularly for drinking, swimming, or recreation. Since fecal coliforms are not harmful themselves but indicate the likelihood of more dangerous bacteria and viruses existing alongside them, their presence is linked directly to the risk of contamination by sewage.

In contrast, the other options do not correlate with the specific implications of fecal coliform presence. Harmful chemicals are not directly indicated by fecal coliform levels; while sewage contamination can introduce chemicals, fecal coliforms specifically pertain to microbial safety. Algae blooms are related to nutrient pollution rather than fecal contamination. Low pH levels refer to the acidity of the water and do not relate to fecal coliform bacteria either. Thus, fecal coliform bacteria serve as an essential marker for monitoring and assessing the microbiological quality of water, particularly in terms