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(38-68) Ecotoxicity of sediment associated Linear Alkylbenzene Sulphonate (LAS) to Lumbriculus variegatus and Caenorhabditis elegans. Webb, Simon*,1, Comber, Sean2, Marshall, Stuart3, Höss, Sebastian4, 1 Procter & Gamble, Stombeek-Bever, Belgium2 WRcNSF3 Unilever4 ECOSSA ABSTRACT- LAS is a major anionic surfactant employed in household products. A fraction of the residual LAS released from wastewater treatment plants tends to be associated with sediments in river systems. The present study assesses the effects of LAS (mean chain length C11.4) to sediment-dwelling organisms. Chronic ecotoxicity studies were conducted with Lumbriculus variegatus (Oligochaete) and Caenorhabditis elegans (Nematode) using spiked sediments. A 28 day chronic study with Lumbriculus variegatus was conducted using sediment spiked with a mixture of cold and radio-labeled material. Nominal exposure concentrations ranged from 50 to 600 mg/kg dw. The lowest NOEC value for survival, reproduction & growth was 81 mg/kg dw based on the mean of day 0 and day 28 measured sediment concentrations. A 3 day chronic study with Caenorhabditis elegans was conducted using sediment spiked with cold-material. Nominal concentrations ranged from 10 to 1,000 mg/kg dw. The NOEC for egg production was 100 mg/kg dw (nominal). Data from these studies in conjunction with other sediment effects data from other species (Chironomus riparius NOEC 319 mg/kg dw) have been used to derive a predicted-no-effect-concentration for LAS in the sediment compartment. A PNEC value of 8.1 mg/kg dw can be derived based on the application of an assessment factor of 10 to the lowest of the three available chronic endpoints. Key words: Sediment, LAS, Lumbriculus, Caenorhabditis |
