Freshwater is a scarce but essential resource, and its quality is of utmost importance as increasing numbers of people and living organisms depend on it for survival. While water scarcity from lack of quantity often receives more attention, water quality becomes more critical than quantity when available water is degraded or polluted. Water quality is important in the ways that it affects human health, livelihoods, agriculture, industry, recreation, and ecosystem services.

Lack of water quality can thus jeopardize socioeconomic development and environmental sustainability, and the availability of clean and good quality water is increasingly recognized as a key factor for sustainable development. Water quality issues are a serious problem in much of the developing world, where lack of access to clean and safe water leads to ...