Benzenesulfonic acid, 4-mono-C20-24 (even numbered)-alkyl derivs., magnesium salts

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

1 mg/L

Assessment factor:

1 000

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

10 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

1 mg/L

Assessment factor:

1 000

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

1 000 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

452 109 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

452 109 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

no hazard identified

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

Derivation of PNECs

The PNECs for the different compartments could be calculated either by application an assessment factor (PNECfreshwater, PNECmarine water, PNECintermittent release and PNECstp) or using the equilibrium assumption method (PNECsediment-freshwater, PNECsediment-marine-water and PNECsoil). The PNECair is not considered as relevant based on the chemical structure of the registered substance. The utilized procedures are described in detail in the ECHA REACH Guidance of May 2008, Chapter R.10 ("Characterisation of dose [concentration]-response for environment").

Environmental classification and labeling

Experimental results of magnesium sulfonate and calcium sulfonate read across substances are available for evaluating biodegradation, metabolism and toxicity of the magnesium sulfonate target substance to aquatic vertebrate and invertebrate species.

None of the magnesium and calcium read across substances was found to be readily biodegradable when tested with OECD Guideline 301D or OECD Guideline 301B (Douglas, 1989 and Sanitised, H., 1995). Thus, a rapid biotic degradation in the environment of the magnesium sulfonate target substance is not expected.

The magnesium sulfonate target substance (CAS 231297-75-9) did not cause any adverse effect on the oxygen consumption of the microbes associated with activated sludge (Goodrich, 1994). The 3h-EC50 for inhibition of metabolism, as represented by respiration, was determined to be > 10000 mg/L.

The acute aquatic toxicity in fish of magnesium sulfonate and calcium sulfonate read across substances was evaluated using several freshwater and marine fish species. In all tests, no toxicity was observed even at the highest test substance concentrations investigated. Pimephales promelas (test with CAS 71786-47-5 by Ward, 1993) and Oncorhynchus mykiss (exposed to CAS 115733-09-0 by Nicholson, 1986) served as freshwater representatives, whereas Cyprinidon variegatus (test with CAS 71786-47-5 by Nicholson, 1986) was used as marine water representative. The experiments were conducted in accordance to OECD 203 and revealed 96h-LL₅₀values of >10,000 mg/L WAF (NOEC 10,000 mg/L in case of C. variegatus) and of > 1000 mg/L WAF (NOEC 1000 mg/L for P. promelas). In a limit test, O. mykiss was exposed only to a single concentration level of 100 mg/L, hence LL₅₀/NOEC amounts to >100/100 mg/L WAF, respectively (Goodband, 2005). 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.

The acute toxicity of magnesium sulfonate and calcium sulfonate read across substances was evaluated in Daphnia magna as representative of aquatic invertebrates. In both experimental studies, no toxicological effect was observed even at the highest concentration level. As in both studies 1000 mg/L WAF was the highest concentration, 48h-EL₅₀revealed > 1000 mg/L WAF, whereas both NOELs were 1000 mg/L (Ward, 1993).

In a study with algae species Selenastrum capricornutum, magnesium sulfonate 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.

Based on the available environmental fate information and due to the lack of toxicity observed in the ecotoxicological studies (aquatic organisms) with magnesium sulfonate and calcium sulfonate read across substances, the magnesium sulfonate target substance (CAS 231297-75-9) needs not to be classified regarding risks to aquatic environment according to Regulation (EC) No. 1272/2008.

Conclusion on classification

The magnesium sulfonate target substance has not to be classified and labelled according to Regulation (EC) No 1272/2008.