What is the MCL for chlorine in drinking water?

The maximum contaminant level (MCL) for chlorine in drinking water is established to ensure the safety of public water supplies. The correct value is 4.0 mg/L. This level is set considering the need to balance effective disinfection practices with potential health risks associated with high chlorine levels.

Chlorine is commonly used in water treatment to kill pathogens, thereby making water safe for consumption. However, excessive levels can lead to undesirable health effects, such as respiratory issues or skin irritations. Therefore, while 1.0 mg/L might seem like a reasonable level for disinfection, the established MCL actually allows for more chlorine use to ensure that water is both safe and meets disinfection requirements.

The chosen answer does not reflect the regulatory guidelines for safe drinking water standards, which are informed by comprehensive research on health impacts and effective treatment practices. Understanding these regulations is crucial for water treatment operators and ensures the delivery of safe drinking water to the public.