Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

not readily degradable

Additional information

Biodegradation in water: screening tests

The ready biodegradability of the test substance was investigated under GLP conditions by means of a CO2 Headspace Test, according to OECD guideline 310. The biodegradation of the test substance was followed by exposing it to microorganisms of non-adapted activated sludge from a municipal wastewater treatment plant. An inoculum control, containing sole pretreated activated sludge, a functional control with the reference substance aniline as well as a toxicity control, including both test item and reference item, was conducted simultaneously. The test concentration selected as appropriate was 20 mg/L TOC, corresponding to approximately 30 mg/L test substance. The flasks were incubated for 28 days at 22 ± 2 °C under aerobic and dark conditions. The biodegradability was derived from TIC analysis of the quantity of CO2 produced within the test period by respiration of bacteria. The mean value of degree of biodegradation was calculated by the single values of five test assays at the end of exposure with a limit of confidence of 95 %.

In result, the required pass level for ready biodegradability was not reached. The degree of biodegradation after an exposure period of 28 days was 0 ± 1 % TIC/TOC. As proven by the toxicity control, no inhibitory effects on microorganisms is expected at the tested concentration of 20 mg/L (degree of biodegradation after 28 days: 41 %).

In conclusion, the test item is not regarded to be in the 10-d-window or after 28 days to be readily biodegradable. Based on determined rate of biodegradation at the end of exposure the test item can be evaluated as poorly biodegradable in this test. All validity criteria were met and no deviations from the test guidelines or other incidents occurred during the course of the reported test which may have influenced. Based on this result, the test substance 1,1-dimethylprop-3-ynylaminehas to be regarded as not readily biodegradable.