Comprehensive chemical characterization and innovative approaches to contaminants’ management for a sustainable environment

Environmental pollution remains one of the most pressing issues worldwide, with chemicals of emerging concern posing significant threats to both ecosystem and human health. The need to address challenges related to these chemicals is recognized by the European Commission’s “Chemicals Strategy for Sustainability towards a Toxic-Free Environment”, while the 5th UN Environment Assembly in 2022, concluded with 14 resolutions to strengthen actions for nature to achieve the Sustainable Development Goals. Therefore, there is a critical need for in-depth characterization of environmental samples not only for providing monitoring data that could support pollution prevention but also for promoting water reuse, ensuring safe and sustainable water resources for future generations.

To address these challenges, cutting-edge high-resolution mass spectrometric (HRMS) methodologies have been developed, for the comprehensive chemical characterization of environmental samples. These methodologies encompass both targeted and untargeted workflows, along with advanced chemometric tools. Several sophisticated software tools have been developed to support nontarget screening (NTS). For instance, a Quantitative Structure–Retention Relationship (QSRR) prediction model has been established to predict the retention time of new compounds [1], while the development of Retention Time Indices (RTI) enables the harmonization of retention times across different laboratories and LC conditions globally [2]. Moreover, a new concept to facilitate identification of unknowns via the effect of pH on their elution patten has been introduced [3]. Additionally, an optimized machine learning model has been devised to predict the most appropriate instrumental method (LC-HRMS, GC-HRMS, or both) for chemical analysis [4], thereby enhancing confidence in suspect and NTS identifications. Furthermore, novel semi-quantification methods have been developed to accurately estimate the concentration levels of newly identified chemicals, even in the absence of reference standards, by considering their ionization efficiency [5,6]. Moreover, innovative trend analysis tools have revealed important patterns of chemicals’ occurrence and fate in environmental samples [7,8]. Recently, a harmonized identification scoring system for LC-HRMS-based NTS has been proposed to the research community [9]. These advanced methodologies have been successfully implemented in numerous environmental monitoring studies worldwide, including investigations in the Danube River [10] and the Black Sea [11], as well as biota samples [12] and wastewater epidemiology studies [13,14].

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