Safeguarding The Security Of Public Water Supplies Using Early Warning Systems: A Brief Review

Water distribution systems are vulnerable to aquaterrorism (terrorism attacks on the water supply) because they are extensive, relatively unprotected, accessible, and often isolated (USEPA 2002, 2003a, Grayman, 2002; Mays, 2004). An emerging activity in the water security arena is developing methods to minimize the public health and economic impacts of a large-scale attack. An intense effort is currently underway to improve analytical monitoring and detection of biological, chemical, and radiological contaminants in drinking water systems as part of the overall effort to secure drinking water supplies (USEPA, 2003b). One approach for avoiding or mitigating the impacts from contamination of a distribution system is to perform monitoring in the context of an Early Warning System (EWS). At present, federal agencies, academic communities, and private companies are working together to develop practical and effective early warning systems. The goal of an early warning system is to reliably identify lowprobability/high-impact contamination events in a distribution system’s finished water, or in source water, in time to permit an effective local response that reduces or avoids entirely the adverse impacts that may result from such an event. The core of an EWS is a monitoring technology that, ideally, would detect or screen for a variety of toxic substances or infectious microorganisms (Brosnan 1999; USEPA 2002). This article briefly reviews the essential elements of an EWS, the relevant plans for developing and implementing an EWS, and the current status and potential for an EWS to ensure the security of drinking water supplies and systems.