Abstract-Concentrations of linear alkylbenzene sulfonates (LAS), dialkyltetralin sulfonates (DATS), and their biodegradation intermediates are reported for the influents and effluents of 10 U.S. domestic wastewater treatment plants as well as upstream and downstream river waters and sediments. Three types of treatment facilities in 10 U.S. states were sampled and analyzed. Removals were calculated based on initial concentrations of LAS and DATS. A derivatization electron capture/gas chromatography/mass spectrometry method was employed. Its increased sensitivity and selectivity permitted the determination of environmental levels of LAS, DATS, and their biodegradation intermediates at low micrograms per liter (ppb) concentrations. The removal from four activated sludge and five trickling filter wastewater treatment facilities averaged 99.5% and 82.9% for LAS and 99.1% and 97.3% for LAS intermediates, respectively, for the activated sludge and trickling filter facilities. In the same plants, percent removals for DATS averaged 95% and 63.2% and DATS intermediates 59.1% and 58.7%, respectively. The removals obtained by a rotating biological contactor were similar to those observed in the activated sludge wastewater treatment facilities.

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Linear alkylbenzene (LAB), the parent material from which the detergent surfactant linear alkylbenzene sulfonate (LAS) is manufactured, has the potential to enter the environment from several sources. Solubility, vapor pressure and soil partition measurements indicate that LAB would be distributed in air or adsorbed to soil or sediment. The material does not accumulate to significant levels in fish (BCF = 35) or undergo chemical or photochemical degradation in screening studies. LAB is readily biodegradable in natural waters with half‐lives for various isomers and homologs in the 4‐ to 9‐day range. LAB is not acutely toxic to a variety of aquatic species, other than Daphnia magna, within its water solubility range. For Daphnia, chronic studies in clean water systems indicate both growth and reproduction to be affected in the 10 to 20 μg/L range. LAB is substantially removed by typical sewage treatment plants. Receiving waters collected from sites receiving low sewage effluent dilution generally contain less than 1 μg/L. Based on the ratio of the chronic no‐effect level for Daphnia to the environmental concentration, the conservative nature of selected monitoring sites i.e., providing low sewage effluent dilution) and the fact that LAB partitions strongly to particulates in the water column, adequate environmental safety margins exist for LAB.