Lindborg, A. R.; Overdahl, K. E.; Vogler, B.; Lin, D.; Sutton, R.; P. Ferguson, L. 2023. Assessment of Long-Chain Polyethoxylate Surfactants in Wastewater Effluent, Stormwater Runoff, and Ambient Water of San Francisco Bay, CA. SFEI Contribution No. 1126. American Chemical Society.

Ethoxylated surfactants are ubiquitous organic environmental contaminants that have received continued attention over the past several decades, particularly as manufacturing rates increase worldwide and as toxicity concerns grow regarding alcohol ethoxylates. Presence of these compounds in surface water has been considered primarily the result of contaminated wastewater effluent by ethoxylated surfactant degradates; as a result, monitoring has focused on the small subset of short-chain ethoxylates in wastewater effluent and receiving waters. This study quantified long-chain alcohol and alkylphenol ethoxylated surfactants in San Francisco Bay area stormwater runoff, wastewater effluent, and ambient Bay water to determine concentrations and inform potential pathways of contamination. We employed high-performance liquid chromatography coupled to high-resolution mass spectrometry to quantitate long-chain polyethoxylates, which are rarely monitored in ethoxylated surfactant studies. Similar total ethoxylated surfactant concentrations were observed in stormwater runoff (0.004–4.7 μg/L) and wastewater effluent (0.003–4.8 μg/L, outlier of 45 μg/L). Ambient Bay water contamination (0.0001–0.71 μg/L) was likely the result of both stormwater and wastewater inputs to San Francisco Bay. These results suggest that a broader focus including long-chain compounds and stormwater pathways may be needed to fully characterize the occurrence and impacts of ethoxylated surfactants in urban surface waters.