Creating Risk Indexes to Evaluate Major Water Pollution Sources

by Chloe Soltis

Water pollution is an issue that affects nearly every country with industrial development. This hazard is not only toxic to the environment but also dangerous to citizens’ health. Yet realistically, no society has unlimited resources or funds to address this concern. Therefore, the creation of a risk indexes (RI) that can systemically identify major sources of water pollution allows countries to more effectively prevent further damage and focus their cleanup efforts at the most hazardous sites. Yao et al. (2015) use a combination of two mathematical models and an expert consultation method to produce integrated risk indexes (RI) that categorizes the risk of different water pollution sources in the Taihu Basin of China. Their study area encompasses Shanghai and the Jiangsu and Zhejiang provinces. The basin struggles specifically with surface water pollution since none of its water samples have met national standards.

Based upon historical environmental issues in the region, Yao et al. determine the five main water pollution sources as waterway transportations, production enterprises, chemical storage sites, waste disposal sites, and non-pointsources. The team identified 2716 pollution sites and evaluated each site for 52 different characteristics. Then, they processed these data through their model, which consists of a piecewise linear function, expert consultation, and a fuzzy integral function. These functions essentially give more or less weight to the 52 different characteristics depending on their environmental importance in addition to normalizing all of the values. The fuzzy integral function is specifically involved in determining risk for these sites. The end result of this process is a risk index (RI) that assigns a number to each pollution site. These numbers allow the team to identify the most hazardous sites for each of the five risk sources.

The Yao team concludes that 52 pollution sites are high-risk, and their study would allow local government officials or policy makers to immediately address the water pollution issues affecting those sites. Risk indexes are unique environmental management tools because they allow countries to prioritize and address the most pressing water pollution issues with their available resources.


Yao, H., Li, W., Qian, X., 2015. Identification of Major Risk Sources for Surface Water Pollution by Risk Indexes (RI) in the Multi-Provincial Boundary Region of the Taihu Basin, China. International Journal of Environmental Research and Public Health 12, 10150-10171.

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