Suspect Screening and Chemical Profile Analysis of Stormwater Runoff Following 2017 Wildfires in Northern California
By Miaomiao Wang, Juliet Kinyua, Ting Jiang, Meg Sedlak, Lester J McKee, Richard Fadness, Rebecca Sutton, and June-Soo Park
Environ Toxicol Chem
May 10, 2022
The combustion of structures, household materials, and firefighting during wildfires leads to releases of potentially hazardous chemicals directly onto the landscape. Subsequent stormwater 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 stormwater discharging to San Francisco Bay and the coastal marine environment, we analyzed stormwater collected after the Northern California wildfires (October 2017) using a non-targeted analytical (NTA) approach. Liquid chromatography quadrupole time-of-flight mass spectrometric (LC-QTOF-MS) analysis was completed on stormwater samples (n=20) collected from Napa County (impacted by Atlas and Nuns fires), the City of Santa Rosa, and Sonoma County (Nuns and Tubbs fire) during storm events that occurred 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 stormwater 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 stormwater, including surfactants, per- and polyfluoroalkyl substances (PFAS), chemicals from consumer and personal care products (PCPs). Homologues of polyethylene glycol (PEGs) were found to be the major contributor to the contaminants, followed by other widely used surfactants. Nonylphenol ethoxylates (NPEs), typically used as surfactants, were detected and much higher in samples collected after storm event 1 relative to storm event 2. The current study provides a comprehensive approach for examining wildfire-impacted stormwater contamination of related contaminants, of which we found many with potential ecological risk. This article is protected by copyright.