LINEAR ALKYLBENZENE SULFONATE (LAS) - UNEP Chemicals

OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS)
containers (as described for springtails). Ten female and five male H.
aculeifer (16-19 days old) were added to each test container together with
100 F. fimetaria (16-19 days old) serving as prey for the mites. Incubation
and extraction of mite offspring followed the same procedure as described for
springtails.
A natural sandy, agricultural soil was used for all tests, rather than synthetic
test soil. Nominal concentrations of LAS for some tests were verified by
chemical analysis using HPLC.
GLP: Yes [ ] No [ ] ? [X]
Test substance: C10-13 LAS was obtained as an aqueous sodium salt solution with an active
matter concentration of 16.1% (w/w), average molecular weight = 342 g/mol,
distribution of the linear alkyl chains: C10 14%, C11 34%, C12 31%, and C13
21%; average alkyl chain length = C11.6
Remarks: Toxic effects on reproduction and growth were revealed when the
concentration in soil exceeded 40 to 60 mg/kg dry weight. Reproduction was
approximately fourfold more sensitive in earthworms and enchytraeids than
in springtails and mites. It is argued that this difference in sensitivity is
related to the dependency of soil pore water, which is high in the annelids but
comparatively low in the arthropods. It should be noted that these studies
report worst case exposures due to the use of a sandy test soil and the fact
that LAS was added as an aqueous solution to the soil. In addition, too few
replicates were used for the ECx approach (e.g., 1000 mg/kg
NOEC = 250 mg/kg soil dw
Method: OECD Guideline 207, 1984. Ten adult worms (mean wt. 0.66 g/animal)
were placed into each of four glass jars per concentration with soil comprised
of 70% 5010 grade silica sand, 20% kaolinite clay, and 10% finely ground
sphagnum peat. Nominal test concentrations in the soil were 1000, 500, 250,
125, 63 and 0 mg/kg dry weight. Temperature was maintained at 20 + /-2 o C
with 24-hour continuous lighting at 600 lux. Earthworms were assessed for
mortality, general health, body weight, and behavior after 7 and 14 days.
GLP: Yes [ ] No [ ] ? [X]
Test substance: LAS (commercial blend) with average alkyl chain length C11.6 (typical of
LAS chain lengths found in the environment).
Remarks: No significant mortality was observed at the highest nominal concentration of
1000 mg/kg. A 33% and 23% reduction in body weight was observed at 100
and 500 mg/kg vs. a 14% reduction for the controls. Based on statistical
analysis of the weight data, the no effect concentration was the nominal 250
mg/kg dose, which was confirmed by HPLC to be 235 mg/kg.
Reference: Mieure, J.P., Waters, J., Holt, M. and Matthijs, E. 1990. Terrestrial safety
assessment of LAS. Chemosphere 21:251-262.
Reliability: 2 Valid with restrictions
UNEP PUBLICATIONS 226