Bioaccumulation of LAS in feral fish studied by a novel LC-MS/MS method

The extent of bioaccumulation of linear alkylbenzene sulfonate (LAS) in feral organisms is presently unknown. To enable LAS determination in biota samples, LAS and its coproducts (methylbranched LAS, dialkyltetralin sulfonates) are extracted from tissues using matrix solid-phase dispersion, isolated by strong anion exchange chromatography and determined by HPLC-electrospray-tandem mass spectrometry. All analytes were quantified in sediment dwelling Tubifex sp. with the sum of the concentrations exceeding 1 micromol/g. Since a portion of LAS was present adsorbed to solids in the guts, the actual body residue was lower than reported lethal LAS body residues. The concentrations of individual constituents in bream muscle samples from the river Saar and fathead minnows caged in the river Arrone ranged up to 2 nmol/g. The apparent bioaccumulation factors in the caged fish are consistently higher than laboratory data, presumably due to a combination of LAS present in the guts adsorbed to suspended material, coingestion of LAS with bacterial detritus, and depressed metabolic activity due to sublethal effects. Given the small deviation between laboratory and field bioaccumulation data and the high detection frequency (> 90%) of C(13)-2- and C13-iso-LAS, the latter two constituents are suitable markers for LAS contamination in fish.