Multi-Methodological Integrated Approach for the Assessment of Diffuse Pollution Background Levels (DPBLs) in Functional Urban Areas: The PCE Case in Milano NW Sector

Abstract

The Milano Metropolitan Area [named FUA (functional urban area)] has a history of heavy industrialization causing a large portion of area being affected by significant diffuse contaminations of soil and groundwater. Among the various contaminants, chlorinated solvents (e.g., tetrachloroethylene and trichloroethylene) are the most used in industrial processes and represent the major cause of groundwater pollution within the FUA. The background diffuse contamination generated by these pollutants is so persistent and widely spread that makes it extremely challenging to identify the sources responsible for their release. Such background contamination originates from the overlapping of both known sources (point sources), associated to specific high release of contamination, and unknown small sources (multiple point sources), clustered within a large area, whose release is low but persistent. The aim of this article is to present the methodology, developed within the framework of the AMIIGA Project (Interreg Central Europe Grant N • CE32), which combines multivariate statistical analysis and groundwater numerical modeling in order to separate the point sources contribution from the background diffuse contamination, and supporting public authorities in the management of groundwater remediation. A methodological workflow is proposed guiding local and regional institutions to use the methodology (i.e., exploratory analysis of big dataset, simulation of groundwater flow and transport, multivariate and geostatistical analysis) to assess diffuse pollution background levels in large urbanized areas.

Stochastic Particle Tracking Application in Different Urban Areas in Central Europe: The Milano (IT) and Jaworzno (PL) Case Study to Secure the Drinking Water Resources

“…This can prevent the huge costs that Water Managers would have to cover in case the contamination enters on the water supply network. In this context, the outcomes of this method are certainly comparable to a transport model (including advection-dispersion) as the extension of non-zero probability areas is quite similar to the plume simulations as presented in [9].…”

“…Functional Urban Areas (FUA, [3]), i.e., large areas composed by an urban core and its commuting zone, compose a unique contamination core where the groundwater is affected by many different kinds of sources, and therefore are difficult to manage. In general, the causes of groundwater contamination can be classified in three different classes [4,5]: (a) Point Sources (PS), hot spots of contamination corresponding to areas releasing plumes of high concentration [6]; (b) Multiple Point Sources (MPS) which are unknown and for which the problem can be faced by using a multi-methodological approach as developed in [7][8][9]; (c) Non-Point Sources (NPS), where the contaminant load comes from the development of anthropogenic activities on large areas (for example pesticides from agricultural practices [10]). In urban contexts, PS contamination (i.e., brownfield, old chemical plant, refineries) are more frequent than NPS (i.e., leakages from agricultural areas [5]).…”

Calculation of Visual Background Values of Major Groundwater Components Taking Karamay City as an Example

“…Currently, there are many methods for analyzing the background value of groundwater [7,13,14], among which mathematical statistics and the pre-selection method are the most used and the most intuitive ways to reflect the background value. Daniele Parrone et al [15] used the pre-selection method to study the volcano-sedimentary aquifers in Central Italy, and the regional NO 3 − concentration was used as an indicator substance to exclude the influence of human activities.…”

Groundwater quality changes in peri-urban areas of the Walloon region of Belgium

“…High population growth and industrial development has increased the demand for freshwater resources during last years and they are expected to become increasingly scarce in the future, partly due to climate change (Aslam et al, 2018). Urban aquifers are more and more considered as a valuable resource for water supply but also for industrial purposes in many countries such as Belgium (SPW-DGO3, 2016), Switzerland (Minnig et al, 2017),Germany (; Hellauer et al 2018) or Italy (Colombo et al, 2020;Pollicino et al, 2021), among others.…”

“…In urban and industrial areas, pollution sources are of various types such as: atmospheric deposition, urban runoff, industrial or domestic wastewater discharges, industrial solid or liquid wastes, gas stations, landfill leakage, septic systems and road de-icing salts, among others (Zhang et al, 2004;Vázquez-Suñé et al, 2010). The addition of point sources close to each other, diffuse pollution and multiple source pollution can also induce widespread contamination of groundwater resources (Rivett et al, 1990, Jamin et al 2012Sorichetta et al, 2012;Colombo et al, 2020;Pollicino et al, 2021).…”