LINEAR ALKYLBENZENE SULFONATE (LAS) - UNEP Chemicals

OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS)
Reference: Gandolfi, C., Facchi, A., Whelan, M.J., Cassarri, G., Tartari, G. and
Marcomini, A. 2000. Validation of the GREAT-ER model in the River
Lambro catchment. 5 th World CESIO Congress. V.2:1370-1379.
Reliability: 2 Valid with restrictions
(i)
Type of Measurement: Background [ ]; At contaminated site [ ]; Other [X] Tiber River
Medium: Sewage treatment plant activated sludge and surface water
Results: The average LAS concentrations in the Roma Nord activated sludge sewage
treatment plant were 4.6 mg/L (influent), 0.068 mg/L (effluent), and 6000
mg/kg dry matter (final sludge), which correspond to an overall 98.5% LAS
removal rate in the plant. In the receiving waters of the Tiber River LAS
was 9.7 µg/L in the aqueous phase and 1.8 mg/kg dry matter in the sediment.
Total daily LAS entering the treatment plant amount to 1150 kg. About
1.5% (17 kg) leave the treatment plant through the final effluent and 234 kg
(about 20% of the influent LAS) are removed by the digested sludge.
Remarks: Samples were collected over several days in June 1993. It is important to
note that LAS environmental fingerprints in effluent and surface waters differ
from the composition of the commercial material. The relative ratio of the
various homologues detected in the aquatic environmental samples is as
follows: C10:C11:C12:C13 = 45:30:23:2 with an average carbon number of
10.8. That is due to the alkyl chain switch to shorter homologues in water as
a consequence of both biodegradation in the water phase, which is faster for
the higher homologues, and of adsorption into sediments, suspended solids,
and the sludge, which is more pronounced for higher homologues. The LAS
homologue distribution in sludge is approximately in the mole ratio
C10:C11:C12:C13 = 7:24:39:30 with an average carbon number of 11.9, as a
consequence of a preferential adsorption of higher homologues.
Reference: DiCorcia, A., Samperi, R., Belloni, A., Marcomini, A., Zanette, M., Lemr, K.
and Cavalli, L. 1994. LAS pilot study at the “Roma-Nord” sewage treatment
plant and in the Tiber river. La Rivista Italiana Delle Sostanze Grasse.
LXXI:467-475.
Reliability: 2 Valid with restrictions
(j)
Type of Measurement: Background [ ]; At contaminated site [ ]; Other [X] Rivers in five
European Countries
Medium: Sewage treatment plant activated sludge, river surface water, sediment
Results: A very high average LAS total removal of 99.2% (98.5-99.9%) in sewage
treatment was found. LAS concentrations in river water below activated
sludge treatment plants in five European countries ranged from