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Environmental fate & pathways

Endpoint summary

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Description of key information

Abiotic degradation

Phototransformation and hydrolysis are the main abiotic degradation pathways for a substance.The magnesium sulfonate target substance (CAS 231297-75-9) is neither susceptible for phototransformation in air, water and soil nor for hydrolysis under environmental conditions.The test substance is a complex mixture (UVCB) for which the test guideline for hydrolysis is not recommended with components having different hydrolytic rates. The representative structure of the test substance contains a phenyl sulphonate functional group and this suggests that hydrolysis at environmentally relevant pH levels and temperatures would not readily occur.

Biotic degradation

The magnesium sulfonate target substance (CAS 231297-75-9) is not expected to be biodegradable based on biodegradation studies with magnesium sulfonate and calcium sulfonate read-across substances.Biodegradability of a calcium sulfonate read-across substance (CAS 70024-69-0) was investigated according to OECD Guideline 301D (key information). The effects of the test substance were assessed based on chemical oxygen demand (COD) measurements using activated sludge from a domestic wastewater plant as inoculum. The test substance attained 8 % degradation during the test duration of 28 days.In a test assigned as supporting information, magnesium sulfonate read-across substance (CAS 71786-47-5; Sanitised, H., 1995) was investigated concerning biodegradability following OECD Guideline 301 B. Activated sludge from a domestic wastewater plant was used as inoculum without pre-adaption. The test substance attained only 1.5 % degradation at the end of the test (after 28 days).

Bioaccumulation

The magnesium sulfonate target substance (CAS 231297-75-9) is not expected to bioaccumulate.Bioaccumulation in aquatic biota is expected for substances possessing a partition coefficient (logPow) in the range of 4.5 to 6 (ECHA Guidance R.11 PBT Assessment). A higher logPow is probably more an effect of solubility than lipophilicity.The magnesium sulfonate target substance (CAS 231297-75-9)possesses a logPow of 22.17 (EPIWIN prediction), thus no strong potential to bioaccumulation is expected. This is supported by the predicted low Bioconcentration Factor (BCF) of 70.8 L/kg (Chemservice S.A., 2012c).Furthermore, based on the assessment of various sulfonates (Sanitised, 2012), the hazard profile does neither meet the B nor the vB criterion.

Transport and distribution

A Mackay Level III fugacity modeling calculation was performed with EPIWIN by Chemservice S.A. (2012b). With a mass amount of 99.4 % for soil, it is clear thatthe magnesium sulfonate target substance (CAS 231297-75-9)will mainly be present in soil and is likely to persist there rather than in other environmental compartments.

A soil adsorption study ofthe magnesium sulfonate target substance (CAS 231297-75-9) is technically not feasible. A prediction with KOCWIN v2.00 revealed a logKoc of 13.3 for C20 alkyl chains. The Henry´s Law Constant is predicted as 0.0613 Pa-m³/mol (Bond-Method, EPIWIN). This value is used in the chemical safety assessment in order calculate the PNECsediment (freshwater and marine water) of themagnesium sulfonate target substance (CAS 231297-75-9).

Additional information