A multi-metric framework integrating source-pathway-receptor factors for groundwater safety assessment of toxic organic pollutants in operating enterprises

Groundwater safety assessment of toxic organic pollutants (TOPs) remains largely concentration-based, limiting its ability to capture risks from operating enterprises and to support proactive management. We proposed a multi-metric framework integrating source-pathway-receptor factors for groundwater safety assessment in operating enterprises, incorporating enterprise emission characteristics (source), hydrogeological and hydroclimatic conditions controlling pollutant migration (pathway), and groundwater protection targets and exposure risks (receptor). To reduce subjectivity, the criteria importance through intercriteria correlation method was combined with the analytic hierarchy process, and the framework was coupled with the DRASTIC model. Non-concentration-based indicators were incorporated to enable prospective assessment under evolving industrial activities. The framework was applied to 327 groundwater monitoring wells across 22 industrial parks in the middle-lower Yangtze River, detecting twenty TOPs, including chlorinated hydrocarbons (CH, n = 2), benzene series (BTEX, n = 3), and polycyclic aromatic hydrocarbons (PAHs, n = 15). TOP occurrence was strongly associated with enterprise production characteristics, with distinct sector-specific patterns. The pollutants in the petroleum, coal, mining, and power industries were mainly PAHs and CH, while those in rubber, plastic, and chemical enterprises were mainly BTEX. 18.15% and 6.86% of enterprises had low and extremely low safety levels, respectively, mostly located along rivers in vulnerable hydrogeological areas with high pollution loads. It was consistent with that of the distribution characteristics of enterprises with high health and cancer risks, although risk classification was stricter. This framework links enterprise sources, migration pathways, and receptor vulnerability, providing a transferable tool for forward-looking groundwater safety assessment and management.