Recent improvements in methodology for the determination of alcohol ethoxylates (AE) in effluents now enable measurement of the full range of AE components, at ng/L levels, in the same analysis. This approach was deployed in effluent monitoring of biofilm and activated sludge wastewater treatment plants from Europe (n ¼ 12) and Canada (n ¼ 8) receiving predominantly municipal effluent. Individual component or ‘‘environmental fingerprint’’ analyses for alkyl carbon numbers C12–C18 and ethoxylate numbers 0–18 were conducted using a derivatization procedure with liquid chromatography/mass spectrometry determination. The AE results were very similar with an overall mean level of 5.7 mg/L (range 1.0–22.7 mg/L). The major contribution to the total AE content was from fatty alcohol, which constituted, on average, 43% of the total. The exposure data can then be corrected to account for alcohol derived from sources other than AE and for sorption to particulate matter to determine AE concentrations in undiluted effluents.
These data can be used with site-specific dilution information to estimate river water exposure in mixing zones and then to determine aquatic risk by integrating normalized AE effect concentrations determined through quantitative structure–activity relationships.