Risk Assessment of Groundwater Organic Pollution Using Hazard, Intrinsic Vulnerability, and Groundwater Value, Suzhou City in China

There is growing evidence of increasing pollution threats to groundwater caused by anthropogenic activities. Risk assessment has proven a useful tool for groundwater management, environmental planning, and decision making in numerous research projects. Based on the origin-pathway-target model, a quantitative evaluation model was established in this study. This study shows that most areas of Suzhou are under medium-to-very high vulnerability to organic pollution, for which the media of the aquifer and the depth of groundwater are responsible. The risk-assessment map shows that the very high-risk areas were mostly distributed in the southeast along with small areas on the northern bank of the river. However, on the groundwater value-weighted risk map, the very high-risk regions were concentrated in the north. Human activities in the industrial area strongly influenced the-risk of organic pollution to groundwater as the areas with very high risks were found mainly in the industrial area. Areas containing very high groundwater value and basic risk class generated a very high value-weighted groundwater contamination risk class. The result of the validation showed that this model was appropriate for groundwater risk assessment for organic pollution in this area. It should be noted that the value-weighted risk map was completely different from the one of the risk map.