To meet the continuous growth of urbanised areas with the ever-increasing demand for safe water supplies, the implementation of new scientifically based methodologies can represent a key support for preventing groundwater quality deterioration.

In this study, a new combined approach based on the application of the Weights of Evidence and the Null-Space Monte Carlo particle back-tracking methods was set up to assess tetrachloroethylene (PCE) contamination due to Point Sources in the densely urbanised north-eastern sector of the Milano FUA (Functional Urban Area). This combined approach offers the advantage of further enhancing the power of each individual technique by integrating both the advective transport mechanism, neglected by the Weights of Evidence, and the influence of specific factors, such as the land use variation, not considered by the Null-Space Monte Carlo particle tracking. To accurately test and explore the performance of this new approach, the analysis was carried out based on the simulation of synthetic PCE plumes using a groundwater numerical model already implemented in a previous study. The Weights of Evidence method revealed that the areas characterised by a groundwater depth lower than 17 m, a groundwater velocity higher than 2.6×10⁻⁶ m/s, a recharge higher than 0.26 m/y and a significant variation of the industrial activities extent are the most susceptible to groundwater pollution. The Null-Space Monte Carlo particle back-tracking has proved to be effective in delineating the potential source zones and contaminant travel path.

The proposed approach can offer additional insights for the protection of groundwater resource. The end-product provides crucial information on the zones that require to be prioritised for investigations and can be easily understood by non-expert decision-makers constituting an advanced tool for enhancing groundwater protection strategies.

为了满足城市化地区不断增长的安全水供应需求，新的以科学为基础的方法的实施可以为防止地下水质量恶化提供重要支持。

在这项研究中，建立了一种基于证据权重和零空间蒙特卡洛粒子回溯方法的新组合方法，以评估人口稠密的东北城市东北地区由于点源引起的四氯乙烯（PCE）污染米兰FUA（功能性市区）的部门。这种结合的方法的优势在于，通过整合被证据权重所忽略的对流传输机制和特定因素（例如土地使用变化等）的影响（Null-Null不考虑），进一步增强了每种技术的功能。太空蒙特卡洛粒子追踪。为了准确测试和探索这种新方法的效果，分析是基于PCE合成烟羽的模拟，使用先前研究中已经实现的地下水数值模型进行的。证据权重法显示，该地区的地下水深度低于17 m，地下水流速高于2.6×10^-6 m / s，高于0.26 m / y的补给量和工业活动程度的显着变化最容易受到地下水污染。Null-Space Monte Carlo粒子回溯已被证明可有效地描绘出潜在的源区和污染物的传播路径。

所提出的方法可以为保护地下水资源提供更多的见解。最终产品提供了有关需要优先进行调查的区域的重要信息，并且非专家决策者可以轻松理解这些信息，从而可以构成增强地下水保护策略的先进工具。