Inventory of pollutants in urban stormwater – documentation report. D4RUNOFF deliverable 1.3

This report represents work carried out in the Horizon Europe project “Data driven implementation of hybrid nature-based solutions for preventing and managing diffuse pollution from urban water runoff – D4RUNOFF”, work package 1 “Novel detection methods for urban runoffs pollutants characterization”, task 1.3 “Screening for CECs, pathogenic indicators, and microbial resistance in urban runoff”.

Together with a draft pollutant inventory, this report constitutes deliverable 1.3 “Library of pollutants from urban runoff in Nature Based Solutions”. The inventory covers identified pollutants in stormwater sampled at the project’s case study stations and other stormwater stations across Europe. The purpose of the documentation report is to document the methodological- and analytical approaches for sampling urban stormwater and quantifying pollutants and other parameters reported in the inventory to aid users of the inventory with respect to data interpretation. The report gives detailed data on different types of urban stormwater origins such as inner-city street runoff, highway runoff, roof- and façade runoff, artificial football field drainage, overflow from combined sewers, by-pass of mixed stormwater at wastewater treatment plants etc. Thorough descriptions of all sampled stations are given in annex 3.

Antibiotic resistance genes in source stormwater were quantified by digital droplet PCR (ddPCR). This method was supported by counts of cultivable antibiotic-resistant Enterobacterales that covers a range of pathogenic or opportunistic pathogenic gut bacteria. The highest antibiotic resistance levels were found in combined sewer overflow and wastewater treatment plant bypass, but antibiotic resistance genes were found in low concentration at most stations. The highest variation was seen for sulfonamide resistance genes that varied more than five orders of magnitude.
Organic micropollutants were analyzed with reversed-phase liquid high-resolution mass spectrometry (RPLC-HRMS, University of Copenhagen) and hydrophilic interaction liquid high-resolution mass spectrometry (HILIC-HRMS, GEUS). Quantitative analyses showed the presence of pollutants that indicate specific pollution sources such as domestic sewage, rubber/tires, and traffic. Suspect screening furthermore indicated the occurrence of various quaternary ammonium compounds and a wide range of additional suspect compounds. Suspect screening is searching for compounds in the HRMS-data based only on mass spectra and retention times (i.e. no standards) by comparison to a list of predefined suspect pollutants.

At the time of report publication, the inventory will be present only in a draft version as some of the analytical methods and interpretation of HRMS data will be refined during the remaining part of task 1.3. The final inventory will be open access when complete.

D4RUNOFF was funded by the European Union’s Horizon Europe research and innovation programme under grant agreement No. 101060638.