Regular monitoring of fecal coliform is necessary to prevent:

Regular monitoring of fecal coliform is crucial because it serves as an indicator of potential health hazards in water sources. Fecal coliform bacteria are found in the intestines of warm-blooded animals and their presence in water indicates that it may be contaminated with fecal matter, which can carry pathogens causing diseases. When fecal coliform levels are elevated, there is a significant risk of waterborne illnesses, which can affect public health, especially in populations relying on untreated or inadequately treated water. Therefore, maintaining safe levels of fecal coliform helps ensure the water is safe for drinking, recreation, and other uses, protecting public health from outbreaks of gastrointestinal and other infectious diseases associated with contaminated water.

The other options do not directly relate to the primary concern of fecal coliform monitoring. For instance, while fish populations and water temperature may be influenced by overall water quality, they are not the primary reasons for monitoring fecal coliform, which is specifically tied to health risks.