What is the desirable range of alkalinity in water?

Alkalinity in water is an important parameter that serves as a measure of the water's capacity to neutralize acids. It is generally caused by the presence of bicarbonate, carbonate, and hydroxide ions, which play a critical role in maintaining pH stability and supporting aquatic life. The desirable range for alkalinity in water, particularly in the context of drinking water and aquatic ecosystems, is typically recognized to be between 30 to 100 mg/l.

This range is preferable because it helps to buffer the water against pH fluctuations, thus protecting aquatic organisms from harmful changes in acidity. Alkaline waters (within this range) support healthy biological processes and are generally more conducive to aquatic life, whereas values significantly lower or higher than this range can lead to issues such as increased acidity or excessive hardness, which can adversely affect both the environment and human health.

In this context, the second option, which specifies an alkalinity range of 30 to 100 mg/l, is most aligned with the criteria set by environmental health guidelines and ensures a balanced ecosystem.