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Biodegradation in water: screening tests

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Description of key information

Dibutylamine is readily biodegradable (according to OECD criteria).

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable
Type of water:

Additional information

The biodegradation potential of dibutylamine (CAS 111 -92 -2) was assessed in a modified MITI test according to OECD 301C (NITE, 1991). Mixed inoculum from 10 different sampling sites was used. After 28 days, a degradation (based on O2 consumption, BOD(NO2)) of 83% was observed. Therefore, dibutylamine was considered to be readily biodegradable according to OECD criteria.

The result is supported by a publication of Calamari and colleagues (1980) using three different sources (river mud bacteria, activated sludge and adapted activated sludge from a wastewater treatment plant) as inoculum in a respirometric assay (Sapromat). The test duration was 12 days. At concentrations of 10 mg/L, 50 mg/L and 100 mg/L, river mud bacteria degraded 98.8 % (BOD/THOD), 13.3% and 2.6%, respectively in 12 days. For activated sludge from a wastewater treatment plant, the results are 121%, 85.6% and 0% (based on BOD/THOD), respectively. Adapted activated sludge degraded 149.2%, 91.3% and 95.3% (BOD/THOD) in 12 days. River mud bacteria were inhibited by dibutylamine at 50 and 100 mg/l, whilst activated sludge bacteria degraded this substance at 50 mg/l and were inhibited at 100 mg/l. Adapted activated sludge showed no signs of inhibition. According to the authors, O2-consumption higher than 100% had to be attributed to differences in endogenous respiration.

In addition, two calculations were conducted to further assess the biodegradation potential of dibutylamine. The substance was within the applicability domain of both models:

- OASIS Catalogic v5.14.1.5, CATALOGIC 301C v11.16: Ready degradable, 70% degradation in 28 days (BASF SE, 2020)

- OASIS Catalogic v5.14.1.5, CATALOGIC Kinetic 301F v14.17: Ready degradable but failing the 10 -d window, 80% degradation in 28 days (BASF SE, 2020)

Therefore, it can be concluded, that dibutylamine is readily biodegradable (according to OECD criteria).