Identification of a PCE Contamination Source in an Intergranular Aquifer Using a Simulation–Optimisation Framework: A Case Study of Ljubljana Polje, Slovenia

Identification of contamination sources is critical for effective remediation planning in contaminated aquifers. This study presents a simulation–optimisation framework that was developed to reconstruct the release history and identify the potential source location after tetrachloroethene (PCE) concentrations that exceeded regulatory limits were detected in production and monitoring wells at the Hrastje well field. The approach integrates a physically based groundwater flow and solute transport model with an evolutionary algorithm to estimate unknown source parameters. The method was tested under realistic field conditions, accounting for the complexity and uncertainty of the subsurface environment. In the optimisation procedure, parameter values converged towards optimal estimates, and the simulated PCE concentrations in monitored wells showed good agreement with the observed values. The delineated source location and the reconstructed temporal and spatial dynamics of PCE contamination in the aquifer provide essential guidance for decision makers in designing and prioritising remediation strategies. By narrowing the potential source area, more targeted and cost-effective field investigations can be planned. The developed model offers a practical tool for evaluating alternative remediation scenarios, supporting adaptive water resource management and safeguarding the drinking water supply.