LINEAR ALKYLBENZENE SULFONATE (LAS) - UNEP Chemicals

OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS)
for physical and behavioral signs of toxicity. Analysis of blood,
biochemistry and urine were conducted. Monkeys were held in individual
wall-mounted cages at a room temperature of 22 + /-1 o C and normal daylight.
Food consisted of 300 g dry diet and bread daily, and fresh fruit on alternate
days. Tap water for drinking was freely available.
GLP: Yes [ ] No [X] ? [ ]
Test substance: C10-13 LAS, activity: 20.5%
Remarks: The SDA/NOTOX report sets a systemic NOAEL of 30 mg/kg/day (oral)
with 0.1 mg/kg/day (sc). However, based on the information provided in the
article and reiterated above, the actual systemic NOAEL is considered to be
150 mg/kg/day (oral) with 0.5 mg/kg/day (sc). According to the authors, the
three combined doses correspond to 100, 500 and 1000 times the estimated
maximum human daily intake.
Reference: Heywood, R., James, R.W., and Sortwell, R.J. 1978. Toxicology studies of
linear alkylbenzene sulphonate (LAS) in rhesus monkeys. I. Simultaneous
oral and subcutaneous administration for 28 days. Toxicology 11:245-250.
Reliability: 2 Valid with restrictions
(n)
Species/strain: Rat (Wistar)
Sex: Female [ ]; Male [X]; Male/Female [ ]; No data [ ]
Administration: Dermal
Exposure period: 15 days
Frequency of treatment: daily
Dose: 0.5 g applied 20 and 30% LAS solutions (about 286 and 427 mg/kg bw d)
Control group: Yes [ ]; No [ ]; No data [ ];
Concurrent no treatment [ ]; Concurrent vehicle [ ]; Historical [ ]
LOAEL: 20% (286 mg/kg bw d) (lowest dose tested)
Results: Body weight gain was suppressed in the 20% group and the body weight was
decreased in the 30% group. An infiltrating, yellowish-reddish brown crust
was observed 2-3 days in the 20% group, and at 1-2 days in the 30% group.
At 4-6 days the crust was abraded and erosion occurred at the abraded site.
Histological examinations of the application site revealed severe necrosis of
the region from the epidermis cuticle to the upper layer of the dermis, severe
infiltration of leukocytes in the necrotic site, diffuse inflammatory cell
infiltration of all layers of the corium. No changes were observed in the
tongue, but the oral mucosa revealed atrophy and slight degeneration of the
epithelium. No systemic effects were observed.
Method: LAS was applied to the backs of the rats. On the 16 th day of the experiment,
skin at the application site and the tissues of the tongue and oral mucosa (to
examine the effects of licking) of the rats that received 30% were examined
histologically.
GLP: Yes [ ] No [X] ? [ ]
Test substance: LAS, activity: 99.9%
Remarks: Information as cited in the IPCS document. Because of necrosis at the
application site, it is not possible to know exactly how much LAS was
absorbed. Effects were probably due to local effects, so the results are best
described as a local LOAEL.
Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs.,
sodium salts. Year 2000 CD-ROM edition.
2) Sadai, M. and Mizuno, N. 1972. Effect of long term topical application of
some anionic surfactants on the skin, oral mucous membrane, and tongue.
Jpn Journal Dermatol. 82:207-221. (in Japanese); cited in: IPCS (1996);
Environmental Health Criteria 169: Linear Alkylbenzene Sulfonates (LAS)
and Related Compounds. WHO, Geneva, Switzerland.
UNEP PUBLICATIONS 279