LINEAR ALKYLBENZENE SULFONATE (LAS) - UNEP Chemicals

OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS)
Test substance: C10-13 alkylbenzene sulfonic acid, sodium salt (CAS #68411-30-3)
Remarks: LAS can be decomposed at extreme conditions such as elevated temperatures
in the presence of inorganic acids such as phosphoric, sulphuric and
hydrochloric acid, e.g.: 60-70% sulphuric acid at 140 - 190 degree C or with
concentrated HCl in a sealed container at 150 - 200 degree C. Information as
cited in IUCLID Data Sheet for CAS #68411-30-3 and in an analytical
textbook.
Reference: Cross, J. and Dekker, M. (ed.). 1977. Anionic surfactants: Chemical
analysis. Vol.8. Pp. 111-115.
Reliability: 4 Not assignable. Original studies not available for review.
3.1.3 STABILITY IN SOIL
(a)
Type: Laboratory
Radiolabel: Yes [X] No [ ] ? [ ]
Concentration: 27.2 mg/kg (Ecosystem Section I) and 16.2 mg/kg (Ecosystem Section II)
(initial amounts in dry soil); 0.44 mg/kg (I) and 0.19 (II) (at end of trials)
Temperature: Room temperature
Dissipation Time: DT50 = 13-26 days
Method: Soil cores taken from two ecosystems were collected and placed in a climate
controlled “plant metabolism box”. Ecosystem Section I consisted of a
heavy clay-like soil. Ecosystem Section II consisted of loose, sandy soil.
Radiolabeled LAS (a defined mixture) absorbed to digested sludge was
incorporated into the soils, after which the soils were planted with either
grass, bush beans and radishes (Section I) or potatoes (Section II). The test
systems were maintained under a defined standard climate (i.e., an average
day in June in Northern Germany) for the vegetative period (76 and 106
days, respectively for Sections I and II). At the end of the growing season
samples were collected from plants and soil and subjected to radioanalysis.
GLP: Yes [ ] No [ ] ? [X]
Test Substance: LAS. The authors state that they tested a defined mixture of LAS, but do not
report the composition in this paper.
Remarks: Correponding to Ecosystem Sections I and II, 63.6% and 72.3% of initial
radioactivity went to the atmosphere (primarily as CO2), 26.8% and 18.3%
were detected in soil cores, 6.6% and 5.9% were present in biomass, and
0.99% and 1.4% leached out with percolated water. The study shows that
LAS adsorbed to digested sludge is relatively rapidly converted to CO2 and,
to a lesser extent, polar organic secondary products in the upper soil layers.
LAS and the secondary products are strongly adsorbed to the topsoil. LAS
introduced into the topsoil by repeated application of sludge did not
accumulate in the soil. Growth of crops is not impaired; the use of LAScontaining
sludge had no adverse effect on the biomass yield (crop yield)
under regulated use conditions.
Reference: Figge, K. and Schoberl, P. 1989. LAS and the application of sewage sludge
in agriculture. Tenside Surf. Det. 26:122-128.
Reliability: 2 Valid with restrictions
(b)
Type : Field trial [ ]; Laboratory [X]; Other [ ]
Radiolabel: Yes [X] No [ ] ? [ ]
Concentration: 0.05 mg/kg
Soil temperature: Probably room temperature
Soil humidity: 80% of water holding capacity
Soil classification: DIN19863 [ ]; NF X31-107 [ ]; USDA [ ]; Other [X] mainly U.S. Soil
UNEP PUBLICATIONS 131