Registration Dossier

Data platform availability banner - registered substances factsheets

Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Environmental fate & pathways

Bioaccumulation: aquatic / sediment

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

The substance not expected to bioaccumulate due to a rapid biotransformation and excretion.

Key value for chemical safety assessment

Additional information

Tolls et al. (2000) determined the bioconcentration of alcohol ethoxylate constituents in flow-through experiment. The BCFs, reported in the publication ranged between <5 and 387.5 L/kg. For the uptake rate constant (k1) a range of 330 - 1660 (L/kg per day) was reported; the determined elimination rate constant (k2) ranged from 3.3 - 59 L/kg per day. According to the authors, the uptake rate constant and the BCF increase with increasing chain length of alkyl chain and decreasing length of the ethoxylate chain. Whereas a decrease in the elimination rate constant was correlated with increasing alkyl chain length and decreasing ethoxylate chain length. The results indicate a rapid biotransformation of alcohol ethoxylates.

The reported BCF-values for alcohol ethoxylates with alkyl-chain length and ethoxylation degree of 12EO8 and C14EO4 were 12.7 and 237 L/kg respectively. For C13EO4 and C16EO8 BCFs of 232.5 and 387.5 L/kg were reported respectively.

In a further publication of Dyer et al. (2008) biotransformation of two surfactants: C12-2-LAS and C13EO8 were tested in subcellular and cellular hepatic systems. The subcellular systems tested were liver homogenates and microsomes from the common carp (Cyprinus carpio) and rainbow trout (Oncorhynchus mykiss). Cellular systems consisted of primary hepatocytes from the common carp (Cyprinus carpio) and PLHC-1 cells, and hepatocarcinoma cells from the desert topminnow (Poeciliopsis lucida). All in vitro systems were exposed to radiolabelled test compounds and assayed for biotransformation using liquid scintillation and thin layer chromatographic methods. Predicted BCF-values corresponded closely to measured values in several fish species, verifying the utility of in vitro systems in refining Kow-only-based BCFs via the inclusion of biotransformation rates.

Resulting from that study biotransformation of C13EO8 could be demonstrated with both, primary hepatocytes and PLHC-1 cells, although with different metabolic profiles. First-order in vitro clearance rates based on exposure of C13EO8 to rainbow trout and carp microsomes and primary hepatocytes from carp lead to predicted BCF-values which were below 98 for all test systems.

In a recent publication of Munoz (2010), in vivo experiments were described which were carried out with pure homologues of linear alcohol ethoxylates. The authors studied the uptake and elimination kinetics, bioconcentration (BCF), biotransformation (identification of the metabolites generated by an organism), and depuration at different exposure levels. Steady state BCF-values ranged from 99.4 to 130 L/kg/d for the tested alcohol ethoxylates. For C12EO6 the rate of uptake (k1) ranged from 63.2 to 122.6 L/kg/d. The rate of uptake was not affected by the exposure concentration. For the rate of elimination (k2) the results showed a very slight decrease with increasing exposure level. As internal degradation products in fish, the glucuronic conjugate of alcohol ethoxylates was detected. The results suggest that predominant biotransformation process for alcohol ethoxylates is a phase II biotransformation. Although the depuration percentage was very high at the beginning of the elimination phase, a slight increase was observed over time. Alcohol ethoxylates were considered to have a delayed elimination and potential of short term bioaccumulation according to Beek (2000).

 

The common principle of the biotransformation of surfactants is either an enzymatic cleavage of the two surfactant molecule moieties (forming a fatty alcohol/acid and a hydrophilic product) or is a terminal oxidation and subsequent stepwise degradation of the alkyl chain (leaving again a hydrophilic product). The metabolism of the surfactant alkyl chain through a combination of omega- and beta-oxidations with subsequent excretion of a short chain derivative has been demonstrated for several fish species (Newsome et al., 1995; Van Egmond et al. 1999).

 

In conclusion, bioconcentration factors of alcohol ethoxylates in the aqueous phase are below the level of concern, and for some nonionic surfactants can be quantitatively related to the length of the hydrophobic and hydrophilic components. There is also evidence that overall molecular size may place constraints on biological uptake. The various studies cited raise no concerns with respect to long-term retention of accumulated surfactant material in tissue, and indeed they present considerable evidence that alcohol ethoxylates are rapidly eliminated and metabolised. Although the fate of metabolites of AE has not been thoroughly studied, rapid biodegradation of alcohol ethoxylates in the aquatic environment is considered to be a mitigating aspect, since the rate of biodegradation of alcohol ethoxylates are significantly faster than the uptake rates of bioaccumulation.

 

 

References:

Dyer, S. D., Bernhard, M. J., Cowan-Ellsberry, C. C., Perdu-Durand, E., Demmerle, S. and Cravedi, J.-P. (2008): In vitro biotransformation of surfactants in fish. Linear alkylbenzene sulfonate (C12 -LAS) and alcohol ethoxylate (C13EO8).Chemosphere 72, 850 -862.

Munoz DA, Gomez-Parra A and Gonzalez-Mazo E (2010) Influence of the molecular structure and exposure concentration on the uptake and elimination kinetics, bioconcentration, and biotransformation of anionic and nonionic surfactants, Environ. Toxicol. Chem, 29 (8): 1721-1734

Newsome, C. S., Howes, D., Marshall, S. J. and Van Egmond, R. A. (1995): Fate of some anionic and alcohol ethoxylate surfactants in Carassius auratus. Tenside Surfact. Deter. 32, 498 -503.

Van Egmond, R., Hambling, S. and, S. (1999): Bioconcentration, biotransformation, and chronic toxicity of sodium laurate to zebrafish (Danio rerio).