Predicted No-effect Concentrations and Risk Characterization of Four Surfactants: Linear Alkyl Benzene Sulfonate, Alcohol Ethoxylates, Alcohol Ethoxylated Sulfates, and Soap

Assessment of aquatic effects requires the derivation of a predicted no-effect concentration (PNEC). In the framework of the Dutch ‘‘Plan of Action Laundry and Cleaning Products,’’ PNECs were derived for linear alkyl benzene sulfonate (LAS), alcohol ethoxylates (AE), alcohol ethoxylated sulfates (AES), and soap. All stages in an aquatic effects assessment were used: initial (assessment factors based mainly on short-term toxicity data), refined (statistical extrapolation based on long-term toxicity data), and comprehensive (field studies). Where necessary (i.e., where other structures had been tested in toxicity tests), the toxicity data were normalized to these structures using quantitative structure–activity relationships (QSARs) for short-term toxicity. Results from statistical extrapolation were compared with field no observed effect concentrations (NOECs), and a final PNEC was derived. Final PNECs for LAS, AE, AES, and soap were 250, 110, 400, and 27 "g/L, respectively. These PNECs were compared with predicted environmental concentrations (PECs) in surface water that were derived from monitoring results of removal of these surfactants in seven representative wastewater treatment plants. It is concluded that for LAS, AE, and AES, the PECs in the environment are about 50 to 100 times lower than the PNECs. The PEC for soap is about equal to the PNEC that is based on acute toxicity data. However, because the available chronic toxicity data for soap demonstrate that this substance is not more toxic than the other three surfactants, there is no reason for concern. On the basis of the results of the risk characterization, it has been concluded in the Netherlands that in properly functioning wastewater treatment plants, the risks for the aquatic compartment from the use of LAS, AE, AES, and soap are low. Keywords—Surfactants Linear alkyl benzene sulfonate Alcohol ethoxylate Alcohol ethoxylated sulfates Soap