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Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Additional information

General considerations

Ecotoxicological investigations concerning fish, aquatic invertebrates and algae were performed with structural analogues of the magnesium sulfonate target substance (CAS 231297-75-9). For the substance itself, experimental data is available concerning toxicity towards aquatic microorganisms. The following read-across substances were used to fulfil the relevant endpoints: Magnesium sulfonate read-across substance (CAS 71786-47-5) and calcium sulfonate read-across substance (CAS 115733-09-0). For the detailed procedure of the read-across principle and justifications, please refer to the separate Read-Across Statement by Chemservice S.A. (2012).

Based on the intrinsic properties of the used substances, Water Accommodated Fractions (WAFs) were prepared for testing. This procedure is in accordance with the OECD Guidance document on aquatic toxicity testing of difficult substances and mixtures (Series on testing and assessment - Number 23; OECD, 2000). The term WAF is applied to aqueous media containing only the fraction of multi-component substances that is dissolved and / or present as a stable dispersion or emulsion. These fractions are prepared individually and not by serial dilution of a single stock WAF. As the term indicates, only a fraction of the total mass of multi-component substances responsible for the composition may be present in the WAF. The "loading rate" is the mass to volume ratio of the mixture to medium used in the preparation. The obtained LL50/ EL50 values are comparable to LC50/ EC50 values, as well as the NOELR (No Observable Effect Loading Rate) to NOEL (No Observable Effect Concentration).

Toxicity to fish

The magnesium sulfonate read-across substance (CAS 71786-47-5) was used in an experiment according to OECD 203 with Pimephales promelas as test organism (Ward, 1993). The NOELR (96h) is reported as 1000 mg/L WAF and the LL50 (96h) is > 1000 mg/L WAF.

Oncorhynchus mykiss was exposed to the calcium sulfonate read-across substance (CAS 115733-09-0) under equivalent experimental 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.

Cyprinodon variegatus (saltwater fish) was used in an experiment in order to determine the toxicity potential of the magnesium sulfonate read-across substance (CAS 71786-47-5) (Nicholson, 1986). The LL50 (96h) is > 10000 mg/L WAF with a corresponding NOELR of 10000 mg/L WAF. 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.

Toxicity to aquatic invertebrates

The magnesium sulfonate read-across substance (CAS 71786-47-5) was used in an experiment conducted in accordance to OECD 202 with Daphnia magna (Ward, 1993). As result, an EL50 (48h) > 1000 mg/L WAF is reported.

The same result was obtained using the calcium sulfonate read-across substance (CAS 115733-09-0) under equivalent test conditions (Ward, 1993).

Long-term investigations are not triggered based upon the chemical safety assessment for freshwater invertebrates.

Toxicity to aquatic algae

In a study with Selenastrum capricornutum magnesium read-across substance (CAS 71486-47-5) served as test substance (Ward, 1994a). The test was conducted according to OECD 201 and revealed an EbL50(96h) of 1100 mg/L WAF and an ErL50(96h) > 1500 mg/L WAF. The corresponding NOELRs are 1000 mg/L WAF, respectively.

The calcium sulfonate read-across substance (CAS 115733-09-0) was tested at nominal concentrations up to 1000 mg/L WAF, whereby no toxicity effects were observed (Ward, 1994b). Thus, the EbL50 (96h) and ErL50 (96h) are > 1000 mg/L WAF.

Toxicity to aquatic microorganisms

The magnesium sulfonate target substance (CAS 231297-75-9) was used in an experiment according to OECD 209. No toxicity was observed, hence EC50 amounts to > 10000 mg/L. The corresponding NOAEC is 10000 mg/L.

Toxicity towards other aquatic organisms

No further investigations are triggered under REACH.