BIOCONCENTRATION OF LAS - EXPERIMENTAL-DETERMINATION AND EXTRAPOLATION TO ENVIRONMENTAL MIXTURES

Linear alkylbenzenesulfonate (LAS) is the most widely used synthetic s urfactant. Environmental risk assessment of LAS requires quantitative information on the bioconcentration properties which, as yet, are unav ailable. Here,we present compound-and isomer-specific bioconcentration data for n-(p-sulfophenyl)alkanes, the constituents of LAS, determine d in flow-through experiments. BGF values ranged between 2 and 1000 L kg(-1). We derived bioconcentration-hydrophobicity relationships and o bserved that bioconcentration factors as well as uptake rate constants increase with increasing log K-OW (estimated) while the elimination r ate constants do not vary with log K-OW. In an attempt to account for the variability of the composition of LAS mixtures, we found the avera ge length of the alkyl chain of the LAS mixture unsuitable for estimat ion of the bioconcentration potential. In contrast, an estimation base d on the composition of the mixture of LAS and the bioconcentration fa ctors of the individual constituents overpredicts measured values by l ess than a factor of 1.5. rising the composition of two LAS mixtures, one typical for LAS in detergents and one representing LAS in rivers, we calculated the respective bioconcentration potentials to be 91 and 22 L kg(-1). This indicates that environmental processes decrease the bioconcentration potential of LAS mixtures.