Benzenesulfonic acid, mono-C11-13-branched alkyl derivs.

Endpoint summary

Key value for chemical safety assessment

Toxic effect type:

dose-dependent

Effects on fertility

Description of key information

The key study is a two year, three generation feeding and reproduction study in rats conducted with structurally similar Linear Alkylbenzenesulfonate (C10-14). The NOAEL reported for this study was 350 mg/kg bw/day (0.5%) based on the absence of test item related effects.

Effect on fertility: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

350 mg/kg bw/day

Study duration:

chronic

Species:

rat

Quality of whole database:

The single study used for this endpoint was given a reliability rating of 2. However, it is a well-documented study that included many reporduction parameters.

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

No specific studies on Branched Alkylate sulphonic acid were available. However, a study is available on analogue linear alkyl benzene sulfonate (LAS or Na-LAS). The LAS structure is a C10 to C13 linear alkyl chain with a para-substituted benzene sulfonic acid sodium salt group attached at any of the secondary alkyl chain carbon positions. The alkyl chain length averages 11.6. LAS is structurally similar to BABS Acid, as both are para C11 -C13 alkylbenzene sulfate (sodium salts). The primary difference is whether the alkyl chain is linear or branched. Based on similar structures and function, LAS is a good analogue for read-across for instances where data are available on it but not on BABS Acid.

LAS (chain length distribution C10-14) was fed for 84 days to 4 groups of weanling rats (3 dose levels, plus control), each dose consisting of 50 animals each of both sexes (PO-generation). When the P0 generation was 107-112 days old, 20 females from each dose group were mated with 20 males from the same group and maintained together for 17 days. The first litters of each generation (Fla- and F2a-generation) were sacrificed at 21 days of age. Ten days after the final litter was sacrificed, all females were remated with different males from the same group to obtain the F1b generation. From the Flb-generation, 20 males and females of each group were selected at weaning to continue their respective diets and to be used for further reproduction studies. Reproduction studies on the F1b and F2b generations were started when the rats were 80 to 85 days old, and were continued until the F3b generation was weaned.

Short description of key information:

General reproduction in rats including fertility, gestation, parturition, neonatal viability, lactation, and post-weaning growth were normal for all test groups and did not vary from controls.  

Justification for selection of Effect on fertility via oral route:

This study was selected as it is a well-documented three generation rat study that inlcuded general reproduction  parameters including fertility, gestation, parturition, neonatal viability, lactation, and post-weaning growth. The resultant NOAEL value was 350 mg/kg bw/day.

Effects on developmental toxicity

Effect on developmental toxicity: via oral route

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

300 mg/kg bw/day

Study duration:

subacute

Species:

mouse

Quality of whole database:

Two studies were available on the analogue substance LAS. First LAS key study is a rat study with a reliabilty rating of 2 study (oral in drinking water on gestation days 6-15) with lowest LOEL (delayed ossification LOEL = 600 mg/kg bw/day); NOAEL = 300 mg/kg bw/day. Second key study is mouse RL=2 study (oral in drinking water on gestation days 6-15) with lowest LOEL (increased fetal loss and reduced litter size considered secondary to maternal toxicity; increased minor skeletal or visceral anomalies at 300 mg/kg bw/day); NOAEL for teratogenicity was 300 mg/kg bw/day. Although the studies had the same NOAEL, the second mouse study is considered more conservative as there was higher maternal toxicity.

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Additional information

No specific studies on Branched Alkylate sulphonic acid were available. However, a study is available on analogue linear alkyl benzene sulfonate (LAS or Na-LAS). The LAS structure is a C10 to C13 linear alkyl chain with a para-substituted benzene sulfonic acid sodium salt group attached at any of the secondary alkyl chain carbon positions. The alkyl chain length averages 11.6. LAS is structurally similar to BABS Acid, as both are para C11 -C13 alkylbenzene sulfate (sodium salts). The primary difference is whether the alkyl chain is linear or branched. Based on similar structures and function, LAS is a good analogue for read-across for instances where data are available on it but not on BABS Acid.

Two developmental studies are available. In one developmental study, female rats were given LAS orally in distilled water from gestation days 6 to 15 during pregnancy. Some effects such as decreased weight gain and transient diarrhea occurred a the highest dose, but pregnancy rates were comparable at all doses and litter parameters were not significantly affected at any dose. No significant differences were observed in visceral anomalies or skeletal variants, with the exception of a marginal retardation of sternabral ossification at the highest dose. The resultant NOAEL was 300 mg/kg bw/d for both maternal toxicity and teratogenicity. In a second developmental study, pregnant female mice were exposed to LAS via gavage on day 6 to 15 of gestation. Increased mortality was observed at the two highest doses (300 and 600 mg/kg bw/day) but not at the next lowest dose (2 mg/kg bw/day). These doses also exhibited retarded weight gain and adverse signs in necropsy. Pregnancy was comparable, however, for all groups. At doses without maternal toxicity, no differences were observed in any parameters. Because of the very wide range between the 2 mg/kg bw/day and 300 mg/kg bw/day doses, the maternal NOAEL of 2 mg/kg bw/day must be considered very conservative. The NOAEL for teratogenicity was 300 mg/kg bw/day.

Based on these combined results the NOAEL used for assessment is 300 mg/kg bw/day.

Justification for selection of Effect on developmental toxicity: via oral route:

Two studies were available on the analogue substance LAS.  First LAS key study is a rat study with a reliabilty rating of 2 study (oral in drinking water on gestation days 6-15) with lowest LOEL (delayed ossification LOEL = 600 mg/kg bw/day); NOAEL = 300 mg/kg bw/day.  Second key study is mouse study with a reliability rating of  study (oral in drinking water on gestation days 6-15) with lowest LOEL (increased fet al loss and reduced litter size considered secondary to maternal toxicity; increased minor skeletal or visceral anomalies at 300 mg/kg bw/day); NOAEL = 300 mg/kg bw/day.

Justification for classification or non-classification

A series of reproductive and developmental toxicity studies are available on the analogue substance LAS. The resultant reproductive toxicity NOAEL was 350 mg/kg bw/day and the resultant developmental toxicity NOAEL based on two studies was 300 mg/kg bw/day. Based on the overall lack of significant developmental or reproductive toxicity at doses that were not maternally toxic in the analogues substance, it is expected that BABS Acid will have a similar profile and therefore would not need to be classified.