LINEAR ALKYLBENZENE SULFONATE (LAS) - UNEP Chemicals

OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS)
3.1.6 Genetic Toxicity
In vitro Studies
Several in vitro bacterial (Ames) tests have been conducted on LAS using Salmonella typhimurium
TA 98, TA 100, TA 1535, TA 1537, and TA 1538 strains with and without metabolic activation at
test material concentrations up to 5000 µg/plate (Schoeberl 1993a; Inoue et al. 1980; Sunakawa et
al. 1981). Results were negative in all studies, while the positive and negative controls gave the
expected results. Similarly, results with and without activation were negative in a recombination
assay using Bacillus subtilis at concentrations up to 50 µg/plate and in an E. coli reverse mutation
assay (Inoue and Sunakawa 1979).
A transformation test with Syrian hamster embryo (SHE) cells without metabolic activation also
showed negative results (Inoue et al. 1980).
In vivo Studies
In vivo mammalian bone marrow cytogenetic studies on LAS exposure are available in which mice
received either oral gavage doses up to 800 mg/kg bw/day (Inoue et al. 1977) or dietary doses up to
1170 mg/kg (Masabuchi et al. 1976). Rats were also given dietary doses up to 450 mg/kg bw/day
(Masabuchi et al. 1976). In all studies, there was no significant difference in the incidence of
chromosomal aberrations between the treated groups and the control groups. A dominant lethal
assay with mice is also available in which male mice received LAS in the diet at a dose of 300 mg/kg
bw/day for 9 months before being mated with untreated females (Masabuchi et al. 1976). There were
no significant differences in fertility, the mortality of ova and embryos, the number of surviving
fetuses, or the index of dominant lethal induction between the experimental groups and the control
group. Three male mice each given a single intraperitoneal injection of 100 mg/kg bw LAS showed
no differences in the incidences of polychromatic erythrocytes with micronuclei in the bone marrow
between the control and treatment group (Kishi et al. 1984). The reliability of each of the in vivo
studies reported here was not assignable because the original study reports were not available for
review. However, they had been evaluated by the International Program of Chemical Safety (IPCS
1996) and therefore are considered reliable.
Conclusion
No indication of genetic toxicity for LAS is evident in any of the studies conducted.
3.1.7 Carcinogenicity
Several studies looked at the potential for tumorigenicity in rats. In the most documented study
(Buehler et al. 1971), four groups of Charles River weanling rats, divided by sex, were given 0.5,
0.1, and 0.02% (10, 50, 250 mg/kg bw/day) LAS in their food for 2 years. Following completion of
those studies, five male and five female rats from each of the parental groups (F1b and F2b) and all
survivors were selected for necropsy. Gross examination of all animals for pathology did not reveal
any abnormalities. No consistent dietary induced changes that could be considered a toxic response
were observed. Animals that showed significant loss of weight, development of tumors, or other
evidence of abnormalities were sacrificed and tissues examined. The incidence of tumors and the
common incidental diseases were similar in all dieting groups.
Other rat studies had similar results with drinking water exposures up to 200 mg/kg bw/day for 24-
26 months (Tiba 1972; Endo et al. 1980) or dietary exposures up to 300 mg/kg bw/day for up to 24
months (Fujii et al. 1977; Yoneyama et al. 1977). No effects were observed on survival, body
weight gain, or general histopathology and hematological endpoints. Slight increases in liver and
UNEP PUBLICATIONS 29