LINEAR ALKYLBENZENE SULFONATE (LAS) - UNEP Chemicals

OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS)
Dominating species (genera) are: Scenedesmus, Selenastrum, Daphnia,
Gammarus, Lepomis, Pimephales and Carassius (71% of the 586 records).
34 of the 93 species are marine species.
-LAS does not have a specific mode of action for different species. The
variability in the sensitivity between species is comparable to the variability
within a species.
-The acute to chronic ratio is approximately a factor 5.
-The mean LC50 of all species is 5.5 mg/L.
-The mean NOEC (chronic) of all species is 0.8 mg/L.
-A quantitative structure activity relationship for chain length was determined
for fish and crustaceans, longer chain lengths corresponding to higher
toxicity. The bioavailability of adsorbed LAS molecules for aquatic
organisms as midge larvae, daphnids and fish is assumed to be low, because
observed toxicity thresholds in the presence of adsorbing material correspond
to the calculated concentration of the fraction LAS dissolved and the toxicity
data for the completely dissolved substance (Pittinger et al., 1989).
Reference: 1) BKH. 1993. The use of existing toxicity data for estimation of the
Maximum Tolerable Environmental Concentration of Linear Alkyl Benzene
Sulfonate, Part I: Main report; Part II: Data base. Study carried out for
ECOSOL, BKH Consulting Engineers, Delft, NL.
2) Hand, V.C., Rapaport, R.A., Pittinger, C.A. 1990. First validation of a
model for the adsorption of linear alkylbenzene sulfonate to sediment and
comparison to chronic effects data. Chemosphere 21(6):741-750.
3) Pittinger, C.A., Woltering, D.M., and Masters, J.A. 1989. Bioavailability
of sediment sorbed and aqueous surfactants to Chironomus riparius (midge).
Environm. Toxicol. Chem. 8:1023-1033.
Reliability: 4 Not assignable
(b)
Results: Neither LAS nor its sulfophenylcarboxylate degradation products displayed
any estrogenic effects.
Remarks: A recombinant yeast estrogen screen using Saccharomycea cerevisiae was
employed to determine the potential estrogenic activity of LAS and its
degradation products.
Reference: Routledge, E.J. and Sumpter, J.P. 1996. Estrogenic activity of surfactants
and some of their degradation products assessed using a recombinant yeast
screen. Environ. Toxicol. Chem. 15:241-248.
Reliability: 2 Valid with restrictions
(c)
Type: Endocrine Disruption
Results: In the yeast screen, no statistical differences in absorbance were induced in
any concentration of either of the three substances. In the hepatocyte assay,
no increase in the concentration of Vg over the concentration of the controls
was observed for LAS or any other three test substances. Results of both
assays indicate that no estrogenic effects occurred after exposure to LAS or
two of its biodegradation intermediates (SPC5 and SPC11).
Method: LAS, SPC5, or SPC11 were prepared in sterile distilled water and added to
the culture media. Two in vitro screening assays for measurement of
estrogenic activity were used: 1) the ER assay, with the recombinant yeast
screen, and 2) the vitellogenin assay, with hepatocytes. ER was used as the
positive control. Serial dilutions of the test compounds were used, with the
maximum concentrations used in the hepatocytes assay were 150 µM (50
mg/L) for LAS, 25 µM (7.4 mg/L) for SPC5, and 200 µM (72.8 mg/L) for
SPC11.
Test Substance: 1) LAS-C11, 47% a.i., supplied by Petroquimica Espanola S.A.
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