Suspect Screening and Chemical Profile Analysis of Storm‐Water Runoff Following 2017 Wildfires in Northern California

Abstract

The combustion of structures and household materials as well as firefighting during wildfires lead to releases of potentially hazardous chemicals directly into the landscape. Subsequent storm‐water runoff events can transport wildfire‐related contaminants to downstream receiving waters, where they may pose water quality concerns. To evaluate the environmental hazards of northern California fires on the types of contaminants in storm water discharging to San Francisco Bay and the coastal marine environment, we analyzed storm water collected after the northern California wildfires (October 2017) using a nontargeted analytical (NTA) approach. Liquid chromatography quadrupole time‐of‐flight mass spectrometric analysis was completed on storm‐water samples (n = 20) collected from Napa County (impacted by the Atlas and Nuns fires), the city of Santa Rosa, and Sonoma County (Nuns and Tubbs fires) during storm events that occurred in November 2017 and January 2018. The NTA approach enabled us to establish profiles of contaminants based on peak intensities and chemical categories found in the storm‐water samples and to prioritize significant chemicals within these profiles possibly attributed to the wildfire. The results demonstrated the presence of a wide range of contaminants in the storm water, including surfactants, per‐ and polyfluoroalkyl substances, and chemicals from consumer and personal care products. Homologs of polyethylene glycol were found to be the major contributor to the contaminants, followed by other widely used surfactants. Nonylphenol ethoxylates, typically used as surfactants, were detected and were much higher in samples collected after Storm Event 1 relative to Storm Event 2. The present study provides a comprehensive approach for examining wildfire‐impacted storm‐water contamination of related contaminants, of which we found many with potential ecological risk. Environ Toxicol Chem 2022;41:1824–1837. © 2022 SETAC

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

“…These chemicals are found in a wide range of commercial and industrial products and used in personal care products, medicines, cleaning products, and polymeric coatings among others. They can also be formed after biodegradation of surfactants and are frequently found in industrial effluents and municipal wastewater. , Furthermore, they were previously identified in surface water associated with storm events. ,,, Finally, as high peak areas of these compounds were detected during the storm and considering the sampling location, the most important source of these compounds is likely road runoff and, thus, can be considered as vehicle-related.…”

“…A feature was tentatively identified only when all experimental fragments (most intense ions) could match predicted ones. In addition, databases from the scientific literature were searched. ,,,,,,− Finally, compounds were classified at different confidence levels …”

“…The main steps have included feature extraction, componentization, and alignment, using specific parameters, such as the total number of features, peak area threshold, blank subtraction, and percentage of occurrence in replicates among others. The features of interest have then been matched against in-house or commercial (open access) databases and evaluated using specific criteria for the identification confidence. ,, Several studies have used HRMS techniques to examine the chemical profile of stormwater and contaminants, with surfactants, additives, plasticizers, pesticides, biocides, flame retardants, vehicle-related compounds, industrial chemicals, and transformation products identified. ,,,,, …”

“…These numerous sources contribute to stormwater with a chemically diverse and complex mixture of compounds. − For instance, the application of pesticides and biocides to green areas and roadside vegetation has been identified as an important source of surface water contamination . Motor vehicles have been reported to be a major source of microplastics, associated with tire wear in creeks, especially following storm events .…”

“…The features of interest have then been matched against in-house or commercial (open access) databases and evaluated using specific criteria for the identification confidence. 5,7,16 Several studies have used HRMS techniques to examine the chemical profile of stormwater and contaminants, with surfactants, additives, plasticizers, pesticides, biocides, flame retardants, vehiclerelated compounds, industrial chemicals, and transformation products identified. 5,7,9,11,16,17 The aim of this work was to investigate the pollutant profile in Australian stormwater (Cubberla Creek, Brisbane) using advanced HRMS techniques and chemometric tools.…”