Bioconcentration of linear alkylbenzene sulfonates and their degradation intermediates in marine algae

Abstract

Sorption experiments using different homologues of linear alkylbenzene sulfonate (LAS) and sulfophenylcarboxylic acid (SPC) on several marine microalgae have been carried out. The steady state seems to be reached in the first 4 hours. Longer exposure times lead to biodegradation of the compound and, therefore, to an overestimation of the bioconcentration factor. Sorption coefficients are higher for Nannochloropsis gaditana, for example, 1,293 Lkg^–1 for C₁₁-LAS and 525 Lkg^–1 for C₁₁-SPC versus 727 Lkg^–1 for C₁₁-LAS and 28 Lkg^–1 for C₁₁-SPC for Dunaliella salina. For both algae an increase in the sorption coefficient is observed when the polarity of the compound decreases (C₅-SPC<C₁₁-SPC<C₁₁-LAS≈C₁₂-LAS). The sorption of C₁₁-LAS on D. salina is fitted to a linear Freundlich isotherm (K=176±0.02, n=0.964±0.02)