Influence of the molecular structure and exposure concentration on the uptake and elimination kinetics, bioconcentration, and biotransformation of anionic and nonionic surfactants

Abstract

In vivo experiments with fish (sole) were performed for pure homologs of linear alkylbenzene sulfonates (LAS) and alcohol ethoxylates (AEO), the most widely used anionic and nonionic surfactants. The surfactant concentration measured in the organism was higher than in the experimental water, and increased with the exposure concentration for both compounds. At the exposure levels tested the bioconcentration factors (BCF) for AEO were one order of magnitude higher than for LAS. Two linear relationships for hydrophobicity were established, one with BCF and the other with uptake rate. The influence of the exposure concentration on the uptake (k(1)) and elimination (k(2)) velocities was researched. The value obtained for k(1) for AEO was higher than for LAS, while k(2) was very similar for both compounds, indicating differences in the incorporation and but not in the depuration rate. For the first time, internal degradation products of LAS were identified and quantified in fish and water and the glucuronic conjugate of AEO was detected in an organism. The predominant biotransformation process for these compounds may be different: the results suggest a phase I biotransformation for LAS and phase II for AEO, due to their different molecular structures.

Global Metabolite Profiling Reveals Transformation Pathways and Novel Metabolomic Responses inSolea senegalensisafter Exposure to a Non-ionic Surfactant

“…Previous work has shown that exposure of S. senegalensis to C 12 EO 6 under the same conditions resulted in steady-state concentrations within the fish after 2–3 days of exposure, with a BCF for the whole fish that was 10-fold higher than that reported for liver in our study . Generally, the BCF values reported for AEOs in whole fish are low and reported to be between 13 and 50 L kg –1 for homologues such as C 12 EO 8 and C 13 EO 8 .…”

“…Previous work has shown that exposure of S. senegalensis to C 12 EO 6 under the same conditions resulted in steady-state concentrations within the fish after 2−3 days of exposure, with a BCF for the whole fish that was 10-fold higher than that reported for liver in our study. 20 Generally, the BCF values reported for AEOs in whole fish are low and reported to be between 13 and 50 L kg −1 for homologues such as C 12 EO 8 and C 13 EO 8 . 23 The elimination percentages were calculated from the decrease in the concentration of the surfactant in the tissues at the end of the 3 day depuration phase (see Table S1 of the Supporting Information).…”

“…8 The marine flat fish Solea senegalensis was selected as the target organism because it is commonly used in marine ecotoxicology studies and has been shown to rapidly accumulate C 12 EO 6 , reaching steady-state concentrations in juvenile whole fish after 2−3 days of exposure. 20 Juvenile fish were exposed to C 12 EO 6 at concentrations of 2-and 6-fold below the NOEC levels. The primary goal of this work was to investigate the nature of the endogenous metabolic changes in fish gills, liver, and blood as a result of surfactant exposure.…”

“…The linear AEO, C 12 EO 6 , was used as the test compound because this is the most abundant AEO homologue in the composition of many cleaning products, is present in dispersant formulations, and is a common homologue detected in surface waters and sediments . The marine flat fish Solea senegalensis was selected as the target organism because it is commonly used in marine ecotoxicology studies and has been shown to rapidly accumulate C 12 EO 6 , reaching steady-state concentrations in juvenile whole fish after 2–3 days of exposure . Juvenile fish were exposed to C 12 EO 6 at concentrations of 2- and 6-fold below the NOEC levels.…”

In Vivo Bioconcentration of 10 Anionic Surfactants in Rainbow Trout Explained by In Vitro Data on Partitioning and S9 Clearance

“…In a second review from 2007, 38 measured BCF values for anionic surfactants representing 10 C 10 –C 13 LASs and 7 perfluoroalkyl acids were judged to be quantitatively reliable . There have since been several other BCF values published for LASs. − Furthermore, BCF values from several unpublished industry studies have been reported, whereby few details are available on the methodology employed . Among the 45 anionic surfactants with a production volume >100 tonnes year –1 registered under REACH, only seven report in vivo BCF data (Table S1).…”