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EC number: 270-115-0
CAS number: 68411-30-3
Five studies are presented. In
the first study (Pickering and Thatcher 1970; van de Plassche et al
1999), fathead minnows were exposed to concentrations of 0.34, 0.63, 1.2
and 2.7 mg/L LAS in continuous flow systems for a total of 196 days.
Each of the four test concentrations plus control received 12 randomly
assigned fish obtained from ponds at the Newtown Fish Farm, Ohio
Division of Wildlife. Pieces of half-tile were placed in each 10-gallon
aquarium for spawning sites. After spawning had been completed, the
cluster of eggs was removed and counted. Four replicates of 100 eggs
from each concentration were reared for 14 days and mortality of eggs
and fry recorded daily. Results indicate that lethality of LAS to newly
hatched fry was the most critical factor found. The 196 day NOEC level
(normalized to C11.6LAS, van de Plassche et al 1999) was 0.63
mg/L. The LOEC was 1.2 mg/L.
In a second study (Chattopahyay
and Konar 1985; van de Plassche et al 1999), the long-term toxicity of
the test substance to fish was determined usingTilapia mossambica(tilapia).
Groups of 15 fish were exposed to concentrations of 0.0, 0.25, 0.38,
0.51, and 1.10 mg/L for 90 days. Test solutions were renewed every 15
days. The feeding rates decreased significantly at 0.25, 0.38 and 1.10
mg/L. In addition, fish showed erratic behaviour, irregular opercular
movement, and at higher concentrations, blood exuded from the base of
the pectoral and pelvic fins and head. No apparent difference in
condition factor (K) was observed at any concentration. The maturity
index (MI) of both male and female fish appeared to decrease at all
concentrations, but the biological significance of this is questionable.
Fecundity decreased at 0.51 mg/L but not at 1.10 mg/L. The gastrosomatic
index (GSI) was significantly different at 0.51 and 1.10 mg/L. Based on
the most reliable endpoints (GSI and fecundity), the NOEC would be 0.38
mg/L and the LOEC would be 0.51 mg/L. However, in view of certain
reporting limitations as described in the dossier, and the fact that
previous evaluations of this study have reported a NOEC of 0.25 mg/L
(van de Plassche et al., 1999), a conservative (protective) NOEC for
this study is considered to be 0.25 mg/L and the LOEC considered to be
In the third long-term study
(Canton and Slooff 1982; van de Plassche et al. 1999), groups of 50
guppies (Poecilia reticulata) were exposed to various
concentrations of LAS for 28 days. Test solutions were renewed three
times per week. The only effect (98% mortality at 10 mg/L) occurred
within 2 days of study initiation. The 28 day NOEC normalized by van de
Plassche et al. (1999) to C11.6LAS was 3.2 mg/L. The 28 day
LOEC was 10 mg/L.
In the key study (Unilever
2010), fertilized eggs of rainbow trout (Oncorhynchus mykiss,
formerlySalmo gairdneri) were exposed to mean measured
concentrations of 0.03, 0.23, 0.35, 0.63, 0.95 and 1.9 mg/L, for 72
days. The responses recorded included the survival of eggs, time to eyed
egg stage, time to hatch, survival and final weight of sac-fry
(eleutheroembryos), and time and extent of swim-up (external feeding).
The lowest NOEC value found was 0.23 mg/L based on survival of eggs
exposed from eyed stage, survival of eggs exposed from fertilization,
survival of sac fry, and overall survival from fertilization to swim-up.
The data are for C11.6LAS and no normalization is required.
Finally, a long term toxicity
test (Maki 1981) to juvenile bluegills (Lepomis macrochirus) was
conducted on C12LAS. Fish growth was determined after 28 days
exposure in a flow-through model ecosystem to measured concentrations of
0, 0.5, 1.0, 2.0, and 4.0 mg/L. Results showed that the growth of
juvenile bluegills was not affected at 0.5 and 1.0 mg LAS/L, but was
reduced at 2.0 and 4.0 mg/L. At the end of the exposure period, fish at
1.0 mg/L LAS had a biomass of 44 gm/m2compared to 10.5 gm/m2for
the 2.0 mg/L concentration. Based on these effects on growth rate, the
NOEC was 1.0 mg/L.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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