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

Endpoint summary

Description of key information

The key study (nine-month drinking water study in rats) reports the NOAEL value of 85 mg/kg bw/day based on activities of glutamate-oxalate transaminase and lactate dehydrogenase and renal Na,K-ATPase.  The NOAEL value of 85 mg/kg bw/day represents the highest NOAEL below the lowest LOAEL in all of the studies and is therefore the appropriate NOAEL for use in the assessment.

Key value for chemical safety assessment

Toxic effect type:

dose-dependent

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

85 mg/kg bw/day

Study duration:

chronic

Species:

rat

Quality of whole database:

The reliability rating of each the four studies performed on the analogue substance Na-LAS was 2.

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

There are repeated dose studies available with BABS Na salt and linear alkylbenzene sulfonate, sodium salt (commonly known as LAS or Na-LAS). LAS is the sodium salt of linear alkylbenzene sulfonic acid with alkyl chain lengths ranging from C10 to C13 and averaging 11.6. The primary 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 carbon positions. BABS Na salt is the sodium salt of branched alkylbenzene sulfonic aicd with alkyl chain lengths ranging from C11 to C13. The primary difference between LAS and BABS Na salt is the alkyl chain, branched vs. linear. Given their structural and functional similarities, LAS and BABS Na salt are good read across analogues for BABS Acid.

In a repeated dose study, groups of 15 male and female rats were fed doses of 0, 50, or 250 mg/kg/day of BABS Na salt or LAS in the diet. Exposure lasted 28 days. Animals were observed daily for clinical signs. Body weights were taken weekly. Blood and urine analyses were done at week 6 and 12 of exposure. At the end of the exposure period, all animals were sacrificed and gross pathology and histopathology exams performed. Rats of both sexes in the high dose BABS Na salt groups showed increased liver weights. Female rats in the high dose LAS group also showed increased liver weights. Males in the high dose LAS group showed increased cecal weights. Based on these endpoints, the 28-day NOAEL for both BABS Na salt and LAS was 50 mg/kg/day. The 28-day LOAEL for both BABS Na salt and LAS was 250 mg/kg/day. The results of this study support the use of LAS as an analogue for read-across to BABS Acid for repeated dose studies.

Three repeated dose studies used LAS for read-across. In the first study, male and female rats were exposed to LAS in drinking water daily for 9 months. Body weight was suppressed in the highest dose group only. Significant decreases in transaminase activity and renal Na, K-ATP-ase was seen in the 0.2% group. The resultant LOAEL and NOAEL values were 145 and 85 mg/kg bw/day, respectively. The NOAEL represents the highest NOAEL below the lowest LOAEL in all the studies. In the second stury, male and female rats were exposed to AS in the diet daily for 6 months. Diarrhoea, suppressed growth, increased cecal weight, and degeneration of renal tubes characterized the highest dose group. Similar but less severe signs were seen in other doses with the exception of the lowest dose of 0.07%, which showed no adverse effects related to exposure to LAS. The resultant LOAEL and NOAEL values were 115 and 40 mg/kg bw/day, respectively. The represents the lowest LOAEL of any study.

In the third study, male and female rats were exposed to LAS via gavage for 28 days. Body weight gain was suppressed, some serum biochemical measures were different from the controls, and some organ weights were either decreased (spleen, heart, thymus) or increased (liver) in either the male or female high dose groups. No mortalities or histopathological abnormalities were observed. The resultant LOAEL and NOAEL values were 250 and 125 mg/kg bw/day, respectively.

Justification for selection of repeated dose toxicity via oral route - systemic effects endpoint:

The resultant LOAEL and NOAEL values were 145 and 85 mg/kg bw/day, respectively. The NOAEL represents the highest NOAEL below the lowest LOAEL of all the studies.

Repeated dose toxicity: via oral route - systemic effects (target organ) urogenital: kidneys

Justification for classification or non-classification

Based on the results of the oral repeated dose studies, the appropriate LOAEL and NOAEL values for use in the assessmenet are 115 and 85 mg/kg bw/day, respectively. These values do not meet the criteria for classification under the DSD or CLP and therefore the substance is not classified.