Aminoiminomethanesulphinic acid

Biodegradation in water: screening tests

Description of key information

Readily biodegradable: 80.6% (O2 consumption) after 28 d (OECD 301C)

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

Two studies are available investigating the biodegradability of aminoiminomethanesulphinic acid (CAS No. 1758-73-2). The key study was performed according to OECD 301C (GLP) with a mixture of activated sludge from STP, freshwater from rivers and lakes, marine water and marine sediment (Anonymous, 1991). 100 mg/L of the test substance was tested for biodegradation. The parameters O2 consumption and the test material analysis using HPLC were used for the estimation of biodegradation. It was found that the test substance formed urea (which further degraded to CO2 and ammonia) and sulfuric acid in the test. After 28 d the test item was degraded to 80.6% based on O2 consumption and 100% based on test material analysis. Since no 10-day window is required and the biodegradation is > 60% the test substance can be regarded as readily biodegradable according to the OECD criteria.
The potential for biodegradation is supported by an additional study according to NEN 3235, Section 5.4 Closed bottle test (Bogers, 1989). An additional study determined the Chemical Oxygen Demand (COD) of the substance (0.415 g O2/g test material; Cardinaals, 1988). The BOD5/ThOD (COD) ratio was used for the estimation of biodegradation for a test substance concentration of 2.0 and 10 mg/L. A biodegradation of 50.6% and 40% (based on COD) resulted for the 2.0 mg/L and 10 mg/L test solutions, respectively. Using the ThOD a biodegradation of 70.9% (for 2.0 mg/L) and 57.4% (for 10 mg/L) resulted. Based on the results it can be concluded that even if 50% of ultimate degradation is not reached based on COD that the substance shows potential for biodegradation.