Benzenesulfonic acid, 4-mono-C20-24 (even numbered)-alkyl derivs., magnesium 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_CAS71786-47-5_OECD 203_Pimephales promelas: LL50 (96h) > 1000 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_CAS71786-47-5_OECD 203_Cyprinodon variegatus: LL50 (96h) > 10000 mg/L WAF

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

1 000 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 magnesium sulfonate target substance (CAS 231297-75-9). 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. The following read-across substances were used to fulfil the endpoint of short-term toxicity to freshwater fish: Magnesium sulfonate read-across substance (CAS 71786-47-5) and calcium sulfonate read-across substance (CAS 115733-09-0). Investigations concerning toxicity in marine fish were performed with the magnesium sulfonate read-across substance (CAS 71786-47-5). For the detailed procedure of the read-across principle and justifications, please refer to the Read-Across Statement (attached to this document).

Acute toxicity to freshwater fish

All available experiments were conducted in accordance to OECD Guideline 203 and under GLP compliance. Based on the intrinsic properties of the used substances, 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.

The toxic effects of the magnesium sulfonate read-across substance(CAS 71786-47-5) were experimentally determined using Pimephales promelas (Fathead minnows) as test organisms (Ward, 1993). Juvenile animals were held for a minimum of 14 days prior to testing and were free of sickness, injuries and abnormalities at the start of the test. 100, 300 and 1000 mg/L WAF loading rates were used as test concentrations. A control group was included, however, no reference substance testing was performed. Control mortality did not exceed the test validity criterion (i.e. < 10 % mortality in controls). No mortality or signs of toxicity were noted in either the control or WAF treatments throughout the exposure time of 96 h. Therefore, the NOELR (96h) is reported as 1000 mg/L WAF, the LL50 (96h) is > 1000 mg/L WAF. Statistical analysis of the data was not warranted on the basis that no mortality occurred in this study.

In a 96-hour acute toxicity study, juvenile Rainbow trouts (Oncorhynchus mykiss) were exposed to the calcium sulfonate read-across substance (CAS 115733-09-0) at nominal concentrations of 0 (control group) and 100 mg/L WAF loading rate under semi-static conditions (Goodband, 2005). 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.

Acute toxicity to saltwater fish

Cyprinodon variegatus (Shepshead minnow) was used as saltwater representative fish in an experiment in order to determine the toxicity potential of the magnesium sulfonate read-across substance (CAS 71786-47-5) (Nicholson, 1986). 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 were mortality or signs of toxicity 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.

Conclusion:

No toxic effects observed in all acute fish studies even at the highest concentration levels tested. The toxicity data available for several acute fish studies (quantified as Water Accommodated Fractions (WAFs)) demonstrate that the substance is not toxic to fish even at the highest test substance concentrations tested (10000 mg/L). The weight-of-evidence indicate that the lower NOECs for O. mykiss are not an indicator of toxicity per se, but are the result of dose selection.Long-term investigations are not triggered based on the observations in acute tests.