LINEAR ALKYLBENZENE SULFONATE (LAS) - UNEP Chemicals

OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS)
Reference: Prats, D., Rodriquez, M., Llamas, J.M., De La Muela, M.A., de Ferrer, J.,
Morena, A. and Berna, J.L. 2000. The use of specific analytical methods to
assess the anaerobic biodegradation of LAS. 5 th World CESIO Congress
V2:1655-1658, Firenze, Italy.
Reliability: 2 Valid with restrictions
(r)
Type: aerobic [X]; anaerobic [ ]
Inoculum: Trickling filters
Medium: Sewage sludge
Results: ROC supported sulfur-limited growth of P. putida. Extensive desulfonation
of ROC was observed.
Method: Other studies have confirmed that LAS is completely biodegradable in
trickling filters and by- products in commercial LAS (e.g., DATS, SPC) are
subject to biotransformation to nondegraded compounds termed refractory
organic carbon (ROC). The current study investigated the further
desulfonation of ROC by a strain of Pseudomonas putida. ROC was
generated from commercial LAS, which served as a carbon source, in a
trickling filter and isolated by solid-phase extraction. The solution of ROC
was then used as a potential sulfur source for the growth of P. putida.
Experiments were conducted in triplicate at 30°C and cultures were aerated
on an orbital shaker. Dissolved Organic Carbon was measured using a total
organic carbon analyzer and HPLC.
GLP: Yes [ ] No [ ] ? [X]
Test Substance: Commercial LAS (Sirene 113)
Remarks: Earlier work shows that the biodegradation and biotransformation of
commercial LAS as a carbon source for growth leads to a residue of
sulfonated aromatic compounds, termed refractory organic carbon (ROC),
from the synthetic by-products. This study demonstrates that this ROC, after
separation from sulfate ion, is utilized extensively as a sulfur source for
bacterial growth. The products of desulfonation are expected to be
biodegradable.
Reference: Mampel, J., Hitzer, T., Ritter, A. and Cook, A.M. 1998. Desulfonation of
biotransformation products from commercial linear alkylbenzene sulfonates.
Environ. Toxicol. Chem. 17:1960-1963.
Reliability: 2 Valid with restrictions
(s)
Type: aerobic [ ]; anaerobic [X]
Inoculum: adapted [ ]; non-adapted [ ]; other [X]; lake sediments
Concentration: 20, 100, and 200 mg/L
Medium: Water
Results: Degradation occurred under anaerobic conditions when exposed to inoculum
obtained from lake sediments. In addition, inocula that were found in aerobic
environments such as compost and activated sludge from a wastewater
treatment plant also showed capability of anaerobic degradation of LAS.
Method: Tests were performed in batch serum vials under anaerobic conditions. The
vials were filled with the appropriate pH 7 medium, autoclaved at 140 o C for
30 minutes, and inoculated with 5 to 10% of the respective inocula. Inocula
originated from several different natural environments and from anaerobic
reactors. LAS was added at three different concentrations (20, 100, and 200
mg/L) plus three sets of controls, all in triplicate. Incubation time was 2
months.
GLP: Yes [ ] No [ ] ? [X]
Test Substance: Mixture of LAS with an alkyl chain length of 9 to 13 units; likely average
alkyl chain length = C11.6
UNEP PUBLICATIONS 164