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

Long-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

fish short-term toxicity test on embryo and sac-fry stages

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 fish parameter 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 fish 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.

Key result

Duration:

72 d

Dose descriptor:

NOEC

Effect conc.:

0.23 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Remarks on result:

other: overall survival (fertilization to swim-up)

Remarks:

The outcome is based on read across to alkylbenzene derivatives (worst case approach)

Details on results:

The result is observed for the highly soluble C10-13-alkyl derivs. sodium salts (worst case approach).

Conclusions:

No chronic fish 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. A 72-day NOEC of 0.23 mg/L from an early life stage test with Rainbow trout (Oncorhynchus mykiss) was used as key value for the PNEC assessment.

Description of key information

  No data on chronic toxicity to fish is available for the target substance. Data from structural analogues (alkylbenzene derivatives) were used to understand the chronic toxicity profile of the target substance to fish. The most conservative approach indicates a 72-day NOEC for fish of 0.23 mg/L. The target substancehowever has a very low water solubility demonstrated using QSAR modelling. Furthermore EPISUITE QSAR modelling was used to predict the chronic ecotoxicity profile of the target substance. Modelled toxicity values for the target substance confirmed that the aquatic chronic toxicity value exceeds the predicted water solubility, leading to the conclusion that it doesn’t exhibit chronic aquatic toxicity. It can be concluded that the target substance does not demonstrate chronic aquatic toxicity at water soluble concentrations

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

0.23 mg/L

Additional information

The target substance is an UVCB. Based on structural and functional similarities, data on LABS Na (CAS no: 68411-30-3) being registered under REACH, are suitable as supporting in case where specific data on the target substance are lacking.

There is no chronic fish study available on the target substance. A study from LABS Na (CAS no: 68411-30-3) was used to cover this endpoint.

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. This value was greater than the predicted water solubility of the target substance.

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 fish.

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