Benzenesulfonic acid, mono-C20-24 (even)-sec-alkyl derivs., para-, sodium salts

Short-term toxicity to fish

Description of key information

Acute toxicity to freshwater fish: 
No toxicity observed even at highest concentration level tested.
RA_CAS68608-26-4_OECD 203_ Oncorhynchus mykiss: LL50(96h) > 100 mg/L WAF,
RA_CAS115733-09-0_OECD 203_Oncorhynchus mykiss: LL50(96h) > 100 mg/L WAF
Acute toxicity to saltwater fish: 
No toxicity observed even at highest concentration level tested.
RA_CAS70024-71-4_OECD 203_Cyprinodon variegatus: LL50 (96h) > 10000 mg/L WAF,
RA_CAS61789-86-4_OECD 203_Cyprinodon variegatus: LL50 (96h) > 10000 mg/L WAF

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

100 mg/L

Marine water fish

Marine water fish

Effect concentration:

10 000 mg/L

Additional information

General considerations

The acute toxicity to fish was investigated for different analogues structures of the C20-24 sodium sulfonate (Benzenesulfonic acid, mono-C20-24 (even)-sec-alkyl derivs., para-, sodium salts). For the substance itself, no experimental data are available. Since all substances used belong to the same chemical group, aryl-alkyl sulfonates, the same behaviour and toxicity potential can be expected. Sodium sulfonate read-across substance (CAS 68608-26-4), calcium sulfonate read-across substance (CAS 61789 -86 -4), calcium sulfonate read-across substance (CAS 115733-09-0) and calcium sulfonate read-across substance (CAS 70024-71-4) were used to fulfil the endpoint of short-term toxicity to freshwater fish. For the detailed procedure of the read-across principle and justifications, please refer to the separate Read-Across Statement (Chemservice S.A., 2016).

Acute toxicity to freshwater fish

In a 96-hour key study, juvenile Rainbow trouts (Oncorhynchus mykiss) were exposed to the sodium sulfonate read-across substance (CAS 68608 -26-4) at nominal concentrations of 0 (control group) and 100 mg/L WAF loading rate under semi-static conditions (Goodband, 2005a).

The experiment was conducted in accordance to OECD Guideline 203 and under GLP compliance. Based on the intrinsic properties of the used substance, Water Accommodated Fractions (WAFs) were prepared for testing. Physico-chemical parameters (i.e. water temperature, pH and dissolved oxygen concentration (DOC)) were recorded daily throughout the test duration of 96 h. No mortalities and no sublethal effects were noted at the highest tested concentration, thus the LL50(96h) is reported to be > 100 mg/L WAF with a corresponding NOELR of 100 mg/L WAF.

In a second key study (Goodband, 2005b), calcium sulfonate read-across substance (CAS 115733 -09 -0) was tested under same test conditions (i.e. Rainbow trout; 96 h exposure according to OECD Guideline 203; single concentration level of 100 mg/L WAF). Again, no toxic effects were observed at this concentration level. Hence, the LL50(96h) is > 100 mg/L WAF, whereas NOELR amounts to 100 mg/L WAF.

Acute toxicity to saltwater fish

Cyprinodon variegatus (Sheepshead minnow) was used as saltwater representative fish in an experiment in order to determine the toxicity potential of the calcium sulfonate read-across substance(CAS 70024-71-4) in a key study by Nicholson (1986b). The acclimatisation period was about 13 days and the biomass loading rate was 0.056 g/L. A control group was included and a single concentration of 10000 mg/L WAF was applied (limit test). The exposure time was 96 h. Sodium lauryl sulfate was used as reference substance, revealing a LC50 (96h) of 1.2 mg/L. Neither in the control nor in any of the treatment groups, mortality or signs of toxicity were recorded. Therefore, the LL50 (96h) is > 10000 mg/L WAF with a corresponding NOELR of 10000 mg/L WAF. No statistical analysis of data was warranted due to the fact that the test substance was found to be non-toxic under the applied conditions.

In another key study (Nicholson, 1986a), calcium sulfonate read-across substance (CAS 61789-86-4) was tested under same test conditions (i.e. Sheepshead minnow; 96 h exposure according to OECD Guideline 203; single concentration level of 10000 mg/L WAF). Again, no toxic effects were observed at this concentration level. Hence, the LL50(96h) is > 10000 mg/L WAF, whereas NOELR amounts to 10000 mg/L WAF.

Conclusion:

No toxic effects observed in all acute fish studies even at the highest concentration levels tested.The weight-of-evidence indicates that the lower NOECs for O. mykiss are not an indicator of toxicity per se, but are the result of dose selection.