Benzenesulfonic acid, methyl-, C20-24 (even numbered) sec-alkyl derivs.

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Justification for type of information:

The long-term toxicity to aquatic invertebrates can be predicted by read across to the alkyl benzene derivitatives category from which the conclusion can be drawn that an increasing carbon chain length causes a decrease in water solubility. Based on this, it can be expected that the long-term toxicity to aquatic invertebrates for benzene sulfonic acid, C20-24 will be very low. Though as a worst case approach, the result of the category member with the highest water solubility value is used as a boundary value. The read across justification document is attached in IUCLID section 13.

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

1.41 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

other: Parent (F0) Survival and reproduction (Total # young in 21 days; and Mean Brood Size)

Remarks on result:

other: Normalised value

Conclusions:

No chronic invertebrate study with the target substance is available. Data generated with the category substance LABS Na is considered pivotal to this endpoint and this is the most conservative approach. The chronic toxicity to aquatic invertebrate of 11.8 LABS Na was determined in a 21 day survival and reproduction test following OECD 211 guideline study. The 21-day NOEC was 1.18 mg/L, based on both survival and reproduction. The 21-day LC50 was 1.67 mg/L (95% CL 1.28 -2.18 mg/L). The 21-day EC50s, based on total young production, average brood size, and % days reproduction occurred, were 1.50, 2.30, and 2.31 mg/L, respectively. The data here are for a C11.8 LAS and when normalized to a C11.6 LAS, the value is 1.41 mg/L (method: van de Plassche et al., 1999). The 21-d NOEC was 1.4 mg/L test substance, which is greater than the water solubility of the test substance.

Description of key information

No data on chronic toxicity to aquatic invertebrates is available for the target substance.  Data from a category member LABS Na (CAS no: 68411-30-3) was used to understand the chronic toxicity profile of the target substance to daphnia. The 21-d NOEC was 1.4 mg/L, which is greater than the water solubility of the target substance.   As a consequence,  the target substance does not demonstrate chronic aquatic toxicity at water soluble concentrations. 

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

1.4 mg/L

Additional information

The EPISUITE QSAR modelling was used to predict the chronic toxicity profile of the target substance. Modelled toxicity values for the target substance confirmed that the aquatic chronic toxicity value exceeds (i) the predicted water solubility, indicating the substance is not soluble enough to measure the predicted effect and (ii) the log Kow cut-off value of 8.0 for chronic toxicity to aquatic invertebrates.

According to data from analogue substance and QSAR modelling of the target substance, the substance does not demonstrate chronic aquatic toxicity at water soluble concentrations.