Assessment of Ethoxylated Surfactants in Wastewater, Stormwater, and Ambient Water of San Francisco Bay, CA

Ethoxylated surfactants are a broad class of ubiquitous organic environmental contaminants used in a variety of commercial and industrial applications. These compounds have received continued attention over the past several decades, particularly as manufacturing rates increase worldwide and certain sub-classes such as alkylphenol ethoxylate surfactants and their metabolites show acute and chronic toxicity concerns, including estrogenic effects. Presence of these compounds in surface water is primarily considered the result of contaminated wastewater effluent, however, other sources such as stormwater runoff have not been comprehensively evaluated. This evaluation is especially important for large urban waterbodies that received multiple point and non-point source inputs. This study quantified various alcohol and alkylphenol ethoxylated surfactants in San Francisco Bay area stormwater runoff, wastewater effluent, and ambient Bay water to determine concentrations and primary pathways of contamination. Methods focused on quantification of long chain polyethoxylates for the various ethoxylated surfactants to 1) compliment previous studies in the Bay area focused on shorter-chain compounds and 2) provide general context for long chain polyethoxylate concentrations, as these are rarely quantified in ethoxylated surfactant studies. High concentrations of ethoxylated surfactants were detected in wastewater effluent, with one site with detected concentrations an order of magnitude higher than other sites. Generally, similar sum ethoxylated surfactant concentrations were observed in stormwater runoff, and contamination was more pervasive, with nearly all target sites having detected ethoxylated surfactant concentrations. Analysis revealed that ambient Bay water contamination, which was relatively low compared to wastewater effluent and stormwater runoff concentrations and limited to only two Bay sites, is likely the result of both stormwater runoff and wastewater effluent inputs to San Francisco Bay.