5-[(2-hydroxyethyl)amino]-o-cresol

Biodegradation in water: screening tests

Description of key information

The ready biodegradability of the test item was determined with a non-adapted activated sludge over a test period of 28 days in the modified Sturm test (OECD 301B) and according to GLP. The test item was tested at a concentration of 16 mg/L with 2 replicates, corresponding to a carbon content (TOC) of 10.3 mg C/L in the test vessels. The test vessels were incubated at low light conditions and at a temperature of 21 -24°C. The biodegradation of the test item was followed by titrimetric analysis of the quantity of CO2 produced by respiration of bacteria. The percentage CO2 production was calculated in relation to the theoretical CO2 production (ThCO2) of the test item. To check the activity of the test system, sodium benzoate was used as functional control. The percentage degradation of the functional control reached the pass level of 60% after the 10 days and a biodegradation of 70% after 28 days. In the toxicity control, containing both test and reference item a biodegradation of 36% was determined within 14 days and it came to 39% after 28 days. The biodegradation of the reference item was not inhibited by the test item in the toxicity control. All the validity criteria were fulfilled according to the Guideline OECD 301B.

The biodegradation of the test item showed that the mean 10% level (beginning of the biodegradation) was not reached until test end. The biodegradation remained in the range 2 -3 % until test end. Under the test conditions the test item is classified as not readily biodegradable in the 10-day-window and within 28 days.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed