MEASUREMENT OF ALKYL ETHOXYLATE SURFACTANTS IN NATURAL-WATERS

Alkyl ethoxylate alcohols (AE) are used in a wide variety of household cleaning products. In order to monitor environmental levels of AE and to determine AE removal during wastewater treatment, an analytical procedure that provides total AE concentration resolved by alkyl chain length for various environmental matrices (influent, effluent, and river water) was developed. The method utilizes a reverse-phase column to extract and concentrate AE from surface waters and wastewaters and utilizes strong anionic and cationic exchange columns to remove potential interferences. AE were reacted with hydrogen bromide to form corresponding alkyl bromide derivatives that were analyzed by capillary gas chromatography with mass selective detection. Recovery of AE from influent, treatment plant effluent, and river water was quantitative (65-102%) over a range of concentrations for all matrices. AE removal was 99% at two activated sludge treatment plants and 92% at two trickling filter plants. Total AE in low dilution (effluent to river water) surface waters downstream from wastewater treatment plants were less than 0.037 mg/L.