High-Resolution Mass Spectrometric Profiling of Stormwater in an Australian Creek

Abstract

Urban stormwater runoff is a major source of pollutants into receiving water bodies. The pollutant profile of stormwater samples collected from an Australian creek during a major storm event in 2020 was investigated using high-resolution mass spectrometry and chemometric tools. The samples were solid phase-extracted and analyzed by liquid chromatography coupled to a quadrupole time-of-flight mass spectrometer (LC-QToF-MS/MS). The detected features were prioritized using two independent but complementary workflows to identify the highly abundant stormwater-related compounds. A total of 174 features were detected at elevated levels during the storm. Four compounds were identified to a confidence level of 1 and 11 at level 2, including nonpolymeric surfactants, plastic additives, rubber and resin-related products, and natural products. Forty two percent were characterized as oligomers such as poly(ethylene glycol) (PEG)-related compounds and octylphenol ethoxylates. Due to a lack of database experimental data, many compounds remained unidentified. Compounds belonging to the same class were clustered using Global Natural Product Social (GNPS) Molecular Networking analysis, highlighting the benefit of this platform in environmental analysis. The prioritization workflow used here is characterized as an effective tool for assessing key stormwater-related compounds and identifying which should receive attention in assessing the environmental effects of stormwater-related chemicals.