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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

RA_CAS 70024-69-0, OECD 301D: 8 % degradation after 28 days (Douglas, 1989)
RA_CAS 71786-47-5, OECD 301B: 1.5 % degradation after 28 days (Sanitised, H., 1995)

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

Comprehensive data are available for magnesium sulfonate and calcium sulfonate read-across substances (CAS 70024-69-0; CAS 71786-47-5). The Read-Across justification is the Annex of the Chemical Safety Report.

A 28-day aerobic ready biodegradability study was conducted with a calcium sulfonate read-across substance (CAS 70024-69-0) using an initial substance concentration of 2 mg/L (Douglas, 1989, OECD Guideline 301D). 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. No pre-adaption was performed. The COD was determined using the Hach semi-micro sample digestion methods followed by direct reading using a Hach DR/2 Spectrometer. Each vessel was incubated twice, the temperature was held constant at 20 +/- 1 °C. For evaluation, sodium benzoate and aniline were used as reference substances, which attained 97 % and 61 % degradation after the incubation period of 28 days, respectively. The test substance attained 8 % degradation. It can be concluded that the substance is not readily biodegradable.

Magnesium sulfonate read-across substance (CAS 71786-47-5; data source: Sanitised, H., 1995) was investigated concerning biodegradability using an experiment in accordance to OECD Guideline 301 B. The assessments were based on carbon dioxide evolution measurements. Activated sludge from a domestic wastewater plant was used as inoculum without pre-adaption to the test substance. Triplicate test vessels were used for the test substance, positive control and the control blank and were incubated at 20-23 °C. Sodium benzoate was used as reference substance and attained 89 % degradation, confirming the validity of the experiment. The test substance attained only 1.5 % degradation at the end of the test (after 28 days). Thus the data indicates that the magnesium sulfonate target substance is not readily biodegradable.