Use of pollutant release and transfer register (PRTR) to assess potential risk associated with chemicals in a drinking water supply facility

Drinking water safety is a serious public health issue. Although the drinking water supply is monitored according to drinking water guidelines, the chemicals released from factories or spills can raise concerns about the quality of drinking water produced at purification facilities. To increase the public trust in drinking water, the reliable control of the source water quality is called for in the framework of catchment management. This paper addresses the problem of the potential risk to a drinking water supply facility from chemical accidents in a basin. The potential risk is defined and assessed as a function of the amount of chemicals transferred, along with their toxicity and distance. Data on the amount of chemical substances transferred to waste treatment facilities are taken from the pollutant release and transfer register, which is an environmental inventory of potentially harmful chemicals. The NFPA-704 health index, which is a standard system from the US National Fire Protection Association, is used for the toxicity. The relative distance between the drinking water supply facility and the location of the transferred chemical is considered. The top-10 chemicals most frequently released in the Nakdong River Basin in South Korea are analyzed using deterministic and stochastic approaches, and cities with high potential risks are identified and prioritized for the efficient monitoring and management of chemicals. Yangsan City, a city located in the southern part of South Korea, is found to have the highest potential risk using these two approaches. This framework can provide decision-makers with useful information for the efficient management of source water in densely populated and highly industrialized catchment areas.