LINEAR ALKYLBENZENE SULFONATE (LAS) - UNEP Chemicals

OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS)
effects were seen on reproduction or embryonic development in either animal
species.
Method: (A) Rat studies
The rats were divided into seven groups consisting of 25 males and 25
females after a five day acclimation period in the laboratory. The tallow
alkyl ethoxy sulfate (55%)-LAS(45%) mixture (TAE3S/LAS) was mixed into
the ground commercial feed at levels of 0.1, 0.5 or 1.0% and fed to two
generations of male and female rats continuously or only to females during
each period of organogenesis (days 6-15) of pregnancy. A control group was
fed the commercial feed with no additive. The parent animals body weights
were recorded weekly for the first eight weeks in each generation and
afterwards recorded only at each mating phase.
Once sexually mature, five rats of each sex per group were sacrificed for
histology during each generation. The remaining rats were mated on a oneto-one
basis three successive times during each generation. The first two
pregnancies (F1a, 1b, 2a and 2b) in each generation were allowed to proceed to
natural births. These pups were counted and inspected for abnormalities at
birth. The third pregnancies in each generation (F1c and F2c) were used for
teratology purposes. At weaning all pups except the F1b litters, which
became the second generation parents, were discarded. Animals for the
second generation were selected on the same basis as previously described
for the first generation. During the third pregnancies of both generations (F1c
and F2c), one-half of each group of females was sacrificed on day 13 of
gestation. A laparotomy was performed and the number of corpora lutea of
pregnancy and the number of implantation and resorption sites were observed
and recorded. On day 21 of gestation, the remaining dams were examined in
a similar manner.
One-third of the fetuses in each of the third litters were examined for skeletal
development and defects. The others were examined for soft tissue defects.
During the teratology period, tissues were collected from five parent females
of each group and from five parent males of the control and continuously
treated groups. The heart, liver, kidneys and gonads were weighed, blood
was taken for routine hemograms, and tissues were set in 10% formalin,
paraffin-sectioned and stained with haemotoxylin-eosin for histopathy.
(B) Rabbit study
Five groups of 25 sexually mature does were distributed on the based on
body weights and litter mates. The does were artificially inseminated with
0.25 mL of undiluted semen, collected from sperm-tested untreated males.
Ovulation was induced by a 1 mg/kg injection of PLH immediately prior to
insemination. The day of insemination was considered day 0 of gestation.
The TAE3S/LAS mixture was administered by gavage from day 2 through
day 16 of gestation at daily doses of 50, 100, or 300 mg/kg of body weight.
Distilled water was the vehicle and each doe received 2 mL of solution per kg
of bodyweight. For the control groups, one received no treatment and the
other received a treatment with water. In order to monitor the dose level, the
females were weighed every three days. The dams were sacrificed on day 28
of gestation and the number of corpora lutea, resorptions and live or dead
fetuses were observed and recorded. The fetuses were removed and treated
and examined for abnormalities.
GLP: Yes [ ] No [ ] ? [X]
Test substance: A mixture of 55% tallow alkyl ethoxylate sulfate (TAE3S) and 45% LAS
(assumed Procter and Gamble products)
Remarks: The authors indicate that rats received up to 6000 times the estimated “worstcase”
human exposure without causing any deleterious effects on the
development or variability of the embryo or fetus. Rabbits also received
UNEP PUBLICATIONS 298