Groundwater Pollution Prevention Zoning in Coastal Industrial Regions Based on a Quantitative Risk Index: A Case Study of the Eastern Hebei Plain, China

In response to the requirements for groundwater pollution risk identification and zoning-based management in typical coastal industrial agglomeration areas, this study takes the coastal industrial zone of the Jidong Plain as the research area and. It develops an integrated evaluation framework for groundwater pollution prevention zoning. The framework is quantitatively centered on pollution source load assessment and groundwater vulnerability analysis, and applies the Analytic Hierarchy Process (AHP) solely as an interpretative and decision-support tool. In this study, the Linear Weighted Function (LWF) method and the DRASTIC model are employed to quantitatively characterize pollution source load intensity (PI) and groundwater system vulnerability (DI), respectively. By constructing a prevention and control index (R) in the form of the product of pollution source load and groundwater vulnerability, the framework achieves an integrated representation of pollution input intensity and the carrying capacity of the groundwater system. The AHP is not directly involved in indicator weighting or zoning calculations; instead, it is applied as a post hoc analytical approach to identify the relative importance of different evaluation factors in groundwater pollution prevention zoning, thereby supporting the interpretation of the zoning results and management priority setting. The results indicate that the overall pollution source load in the study area is relatively low, with low-to-moderately low load zones accounting for 68.7% of the area. In comparison, high-load zones account for only 1.43% and are mainly concentrated in the southeastern coastal industrial belt. Shallow groundwater generally exhibits high vulnerability, with highly vulnerable zones covering 86.56% of the area and predominantly distributed in the northeastern Quaternary unconsolidated sedimentary regions. Based on the prevention and control index (R), the study area is classified into prevention zones and remediation zones. Prevention zones account for 94.47% of the total area, whereas remediation zones account for 5.53%. High-risk areas are mainly concentrated in coastal industrial belts and highly vulnerable cultivated areas. The results demonstrate that the proposed integrated evaluation framework effectively couples pollution source load and groundwater vulnerability, and, on the basis of the finalized zoning results, enhances the interpretability and management specificity of the zoning outcomes through post hoc decision-support analysis, thereby providing a scientific basis and methodological reference for groundwater pollution prevention zoning and differentiated management in coastal industrial regions.