What is the MCL for copper in mg/l?

The maximum contaminant level (MCL) for copper is established at 1.3 mg/l in drinking water. However, for this question, the closest option in the provided choices pertains to what is commonly known. The rationale behind this value is rooted in protecting public health, particularly considering the potential health effects that can arise from elevated levels of copper. Excess copper can lead to gastrointestinal distress and long-term exposure may result in liver and kidney damage.

In the context of the answer provided, it's consistent with common regulations guiding the management of drinking water quality. It’s important to focus on maintaining copper levels well below the MCL to ensure consumer safety. Understanding MCLs helps water operators and regulators manage water quality effectively, thereby ensuring that drinking water is safe for public consumption.