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-eff ect concentration (PNEC). In the framework of the Dutch "Plan of Action Lau ndry and Cleaning Products," PNECs were derived for linear alkyl benzene su lfonate (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 (sta tistical extrapolation based on long-term toxicity data), and comprehensive (field studies). Where necessary (i.e., where other structures had been te sted in toxicity tests), the toxicity data were normalized to these structu res using quantitative structure-activity relationships (QSARs) for short-t erm toxicity. Results from statistical extrapolation were compared with fie ld 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 mu g/L, respectively. These PNECs were compared with predicted environmental concen trations (PECs) in surface water that were derived from monitoring results of removal of these surfactants in seven representative wastewater treatmen t plants. It is concluded that for LAS, AE, and AES, the PECs in the enviro nment are about 50 to 100 times lower than the PNECs. The PEC for soap is a bout equal to the PNEC that is based on acute toxicity data. However, becau se the available chronic toxicity data for soap demonstrate that this subst ance 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 wastewat er treatment plants, the risks for the aquatic compartment from the use of LAS, AE, AES, and soap are low.