Groundwater contamination risk assessment using intrinsic vulnerability, pollution loading and groundwater value: a case study in Yinchuan plain, China.

Groundwater contamination risk assessment is a useful tool for groundwater pollution prevention and control. Previous study has evaluated groundwater contamination risk at Yinchuan Plain, China, according to aquifer vulnerability. The present study enriches the assessment of contamination risk by adding pollution loading, which represents the hazard from human activities, and groundwater value, which represents the economic loss as a result of groundwater pollution. An approach that combines toxicity, release possibility, and the potential release quantity of pollutants on the ground surface was used to estimate the pollution loading. An integrated approach that considered both the in situ and extractive values was used to estimate groundwater value. In addition, a basic risk map was constructed by overlying the vulnerability and pollution loading maps showing the potential probability of pollution, while a value-weighted risk map was produced by overlying the basic risk and value map indicating the urgency of protection. The validation by specific contaminants shows the reliability of the basic risk assessment. Both the basic and value-weighted risk maps indicate a very high groundwater contamination risk in Yinchuan City, and the southern part of Yinchuan Plain exhibited a relatively high contamination risk. As a result of not only high vulnerability but also very high pollution loading and groundwater value, Yinchuan City is the most urgent area requiring groundwater protection. The produced maps provide effective information for decision-making regarding the optimization of monitoring network, preferential treatment, and allocating future potentially hazardous.