Characterization of anionic surfactant-induced toxicity in a primary effluent

A simple and rapid analytical approach was developed that can be used to investigate the anionic surfactant-induced toxicity associated with the primary effluent from the Lions Gate wastewater treatment plant (North Vancouver, BC). Using this approach, the effluent was characterized on two occasions in terms of anionic surfactant concentration and anionic surfactant-induced toxicity. The results suggest that the concentration of anionic surfactants, measured as methylene blue active substances (MBAS), in the primary effluent increased throughout each day and was highest at night (11:30 p.m.). The toxicity, measured using Vibrio fischeri bioassays (i.e., MicroTox™), also increased throughout each day and was the highest at night. The high molecular weight fraction of anionic surfactants was identified as the most toxic fraction although it was present at the lowest concentration. The results of the present study suggest that the concentration of the high molecular weight fraction of anionic surfactants could be used as a good surrogate to easily and rapidly quanitfy the anionic surfactant-induced toxicity of the primary effluent.