Acute Toxicity of LAS Homologues in Marine Microalgae: Esterase Activity and Inhibition Growth as Endpoints of Toxicity

The toxicity of two linear alkylbenzene sulfonate (LAS) homologues (C10 and C13) was evaluated in four marine microalgae (Nannochloropsis gaditana, Tetraselmis suecica, Rhodomonas salina, and Isocrysis galbana), using growth inhibition rate and esterase activity (measured by flow cytometry) as endpoints. The inhibitor effect was higher for the C13 LAS homologue than for C11, in both responses analyzed. When both endpoints were compared, the growth inhibition rate was between 2 and 5 times more sensitive than esterase activity. Among microalgae species, R. salina exhibited the highest sensitivity.