What is the maximum contaminant level (MCL) for coliform bacteria in water?

The maximum contaminant level (MCL) for coliform bacteria is significant because it reflects the level of safety for drinking water and other uses. The MCL for coliform is set at 1.0 colony-forming units (CFU) per 100 milliliters in a sample. This standard is established to ensure that water is sufficiently free from pathogens that could cause human illness.

Coliform bacteria are indicator organisms commonly found in the environment, specifically in soil, vegetation, and the intestines of warm-blooded animals. The presence of coliform bacteria in water indicates possible contamination by fecal matter, which can contain harmful pathogens. Thus, maintaining a low MCL such as 1.0 per 100 mls is crucial in water treatment and public health management to ensure the safety of the water supply.

Higher MCL values suggested in other options may imply a lower standard of water quality, which would not align with public health guidelines aimed at minimizing potential health risks.