Comprehensive characterization of microcontaminants in urban runoff: Unveiling chemical signatures using wide-scope target screening by LC-HRMS
M. Isabel Cadena-Aizaga, E. García-Gómez, Pablo Gago-Ferrero, Sergi Sabater, Mira Petrović
Abstract
Urban runoff represents a non-point source of emerging contaminants (ECs) to aquatic ecosystems, indicating a potential risk to aquatic organisms. In this study, runoff from three cities was analysed during four rainfall episodes between 2023 and 2024, complemented by one simulated rainfall experiment conducted across different industrial and residential areas. Wide-scope target screening methodology was successfully applied to analyse a wide variety of ECs, encompassing 759 unique compounds. These include tyre-related and other industrial compounds, antibiotics, personal care products, pesticides, pharmaceuticals and their transformation products and metabolites, among others. From the screened target analytes, a total of 255 compounds were identified, of which 92 were quantified. Tyre-related and other industrial compounds emerged as the most frequently detected and abundant substances in urban runoff samples. ECs profiles were similar across all study locations, although notable variations in concentrations were observed, with peak levels occurring at the onset of rain episodes. Among the ECs detected, the tyre-related compound 1,3-diphenylguanidine (DPG) was detected at high frequencies and concentrations in all analysed sites, suggesting its reliability as an indicator of traffic-related pollution. Additionally, compounds such as DPG and the pesticide imidacloprid exceeded their Predicted No-Effect Concentrations (PNEC) levels by several orders of magnitude, highlighting the environmental impact of urban runoff as a transport mechanism for ECs into aquatic environments. • Suspect and wide-scope target screening approaches were applied to determine emerging microcontaminants. • Emerging microcontaminants were identified and quantified in urban runoff from multiple Spanish cities. • Tyre-related compounds were frequently detected across all study sites. • 1,3-Diphenylguanidine showed highe concentrations and detection rates, indicating its potential as a traffic pollution tracer. • Several compounds exceeded ecological safety thresholds based on their Predicted No-Effect Concentrations (PNECs).