Bioconcentration of LAS:  Experimental Determination and Extrapolation to Environmental Mixtures

Abstract

Linear alkylbenzenesulfonate (LAS) is the most widely used synthetic surfactant. Environmental risk assessment of LAS requires quantitative information on the bioconcentration properties which, as yet, are unavailable. Here, we present compound- and isomer-specific bioconcentration data for n-(p-sulfophenyl)alkanes, the constituents of LAS, determined in flow-through experiments. BCF values ranged between 2 and 1000 L kg-1. We derived bioconcentration−hydrophobicity relationships and observed that bioconcentration factors as well as uptake rate constants increase with increasing log K OW (estimated) while the elimination rate 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 average length of the alkyl chain of the LAS mixture unsuitable for estimation of the bioconcentration potential. In contrast, an estimation based on the composition of the mixture of LAS and the bioconcentration factors of the individual constituents overpredicts measured values by less than a factor of 1.5. Using 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.

Bioconcentration, biotransformation, and chronic toxicity of sodium laurate to zebrafish (Danio rerio)

“…Chem. 18,1999 469 L laurate that died after 4 to 6 d of exposure had a body burden of 754 mg/kg (3.8 mmol/kg). Fish that survived to the 28-d test showed increasing body burdens with increasing exposure concentrations.…”

“…Many toxicity tests on soap have been carried out using concentrations that exceed the water solubility (estimated solubility of 3 mg/L for C 12 to 0.0006 mg/L for C 18 in hard water) of the soap in the test medium [1]. In tests in which concentrations exceed the solubility limit, interpretation of effects may be difficult because undissolved material is unlikely to contribute significantly to toxicity [3].…”

Assessment of the Use of Partitioning and Interfacial Tracers To Determine the Content and Mass Removal Rates of Nonaqueous Phase Liquids

“…Hexadecane (99%) was obtained from Acros (Geel, Belgium). Pure samples of 5-n-(p-sulfophenyl)undecane and 5-n-(p-sulfophenyl)dodecane were kindly provided by Dr. J. Tolls (16). Silica 60 (Merck), sea sand (Merck), controlled pore glass (CPG-10-3000, Electro Nucleonics Inc., Fairfield, NJ), fine glass beads (ABCR, Karlsruhe, Germany), and coarse glass beads (Fisher Scientific, Den Bosch, The Netherlands) were used as model matrices ( Table 1).…”

Laundry Detergents, 4. Ecology and Toxicology

“…While in some cases a bioaccumulation in fish can be definitely excluded (e.g., alcohol sulfates), in other cases only the bioconcentration of the radioactivity in the piscine body was determined without differentiation between the parent compound and the biotransformation products. A detailed investigation of the bioconcentration behavior of several n-(p-sulfophenyl)alkanes, i.e., constituents of LAS, revealed that these chemical structures are not or only moderately bioaccumulative not the least due to the action of biotransformation processes [55]. Table 7, they easily fulfill the legal requirements of a minimum primary biodegradability of 80 % BiAS removal and are ''readily biodegradable'' in the OECD tests on ultimate biodegradability.…”