A Review of Sensing Systems and Their Need for Environmental Water Monitoring.

Water is a valuable natural resource and is needed to sustain human life. Water pollution significantly jeopardizes clean drinking water supplies, it is hazardous to human health, and it inhibits economic development. Well-designed sensors that can continuously monitor water quality during transport and identify contaminants in the watershed help effectively control pollution and thereby manage water resources. However, the commercially available sensors are expensive and require frequent maintenance. These limitations often make these sensors inadequate for continuous water monitoring applications. This review evaluates many sensors based on colorimetric, electrochemical, and optical sensors. Sensors suitable for estimating the amount of dissolved oxygen, nitrates, chlorine, and phosphates are presented. A review of recently developed high quality sensors for measuring the previously mentioned components of water is also presented. Future directions in this area of developing high quality sensors for water monitoring are discussed.