LINEAR ALKYLBENZENE SULFONATE (LAS) - UNEP Chemicals

OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS)
Type: aerobic [X]; anaerobic [ ]
Inoculum: adapted [ ]; non-adapted [ ]; None Stated
Concentration: 15 mg/L related to COD [ ]; DOC [ ]; test substance [X] HPLC
Medium: water [X]; water-sediment [ ]; soil [ ]; sewage treatment [ ]
Degradation: 95% after 6 days
Results: readily biodeg. [ ]; inherently biodeg. [ ]; under test condition no
biodegradation observed [ ], other [X]
Method: LAS and water collected from a briny pond (salinity: 9.5 g/L) were tested in
an aerated cylindrical reactor at 21 o C. Samples were removed periodically
and analyzed for parent compound and metabolites by HPLC.
GLP: Yes [ ] No [ ] ? [X]
Test substance: LAS (CAS #25155-30-0); activity: >99%; average alkyl chain length = C11.6
Remarks: The half-life of LAS was 1.5 days. The HPLC method employed accurately
defines the metabolites formed by primary biodegradation. All metabolites
were not persistent and rapidly underwent further biodegradation.
Reference: Sarrazin, L., Arnoux, A., Rebouillon, P. and Monod, J.L. 1997.
Biodegradation of linear alkylbenzenesulfonate (LAS) in briny water and
identification of metabolites using HPLC analysis by direct injection of
samples. Toxicological and Environmental Chemistry. 58:209-216.
Reliability: 2 Valid with restrictions
(n)
Type: aerobic [X]; anaerobic [ ]
Inoculum: adapted [ ]; non-adapted [X]; activated sludge
Concentration: 1 mg/L related to COD [ ]; DOC [ ]; test substance [X]
Medium: Activated sludge
Degradation: >96% after 6 hours
Results: Primary and complete biodegradation were described by a first-order model,
with rate constants of 0.96-1.10/h (t½ = 0.63–0.72 h) for primary loss and
0.50-0.53/h (t½ = 1.30–1.38 h) for complete degradation.
Method: Radiolabeled LAS was dosed at an environmentally relevant concentration
into biotic and abiotic activated sludge. Activated sludge mixed liquor was
used from two STP (Polk Run and Sycamore) near Cincinnati. Standard
methods were used and the test flasks (reactors) were maintained at 20 + /-2 o C.
GLP: Yes [ ] No [ ] ? [X]
Test Substance:
14 C [uniform ring] C12 LAS
Reference: Federle, T.W. and Itrich, N.R. 1997. Comprehensive approach for assessing
the kinetics of primary and ultimate biodegradation of chemicals in activated
sludge: Application to linear alkylbenzene sulfonate. Environ. Sci. Technol.
31:1178-1184.
Reliability: 2 Valid with restrictions
(o)
Type: aerobic [ ]; anaerobic [X]
Methods: Experiments were conducted in which enriched cultures of anaerobic bacteria
were provided with 60 µmole/L LAS as the sole source of sulfur. Conditions
were maintained anoxic in salts-medium containing several sources of
carbon.
Results: Strain RZ LAS, an anaerobic bacteria, was isolated from wastewater
treatment plants in Germany. RZLAS was shown to degrade LAS,
indicating that microorganisms able to metabolize LAS in anaerobic
conditions exist in nature.
GLP: Yes [ ] No [ ] ? [X]
Test Substance: Commercial C10-13 LAS (CAS #68411-30-3; average alkyl chain length =
C11.6) and C12 LAS (pure homologue)
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