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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

A large number of tests on biodegradability are available for o-toluidine. In the following the tests that were conducted according to standard methods are presented. Several experimental data prove that o-toluidine is readily biodegradable.

The biodegradability of o-toluidine under the conditions described by the OECD TG 301 A and E was tested by 6 different laboratories. All the laboratories followed the same procedure. Based on DOC measurement the following results were obtained after 28 days: with the method OECD TG 301 E, five laboratories obtained > 90 % biodegradation, the other one reported a 67 % value. The results obtained with the method OECD TG 301 A showed biodegradation between 88 and 90 % after 28 days. In all cases the 10 d-window criterion was fulfilled.

According to the national Japanese standard method comparable to the OECD TG 301 C guideline an aerobic ready test was performed. Related to BOD after a period of 28 days 65.4 % biodegradation was observed. No information is given in relation to the 10 d-window.

Results on the inherent biodegradability of o-toluidine are also available.

A test on inherent biodegradability was conducted. The test design is comparable to the Zahn-Wellens-Test (OECD TG 302 B). The test substance o-toluidine in a concentration of 200 mg/L COD was the sole source of carbon. Activated sludge from a sewage treatment plant adapted for 20 days to o-toluidine was used as inoculum in a concentration of 100 mg/L dry matter.

Based on COD measurement, a removal of 97.7 % within 5 days was obtained.

With adapted activated sludge from an industrial sewage treatment plant a test on inherent biodegradation was conducted. The procedure followed the OECD guideline 302 B. After 11 days (4 days adaptation) 96 % of the initial concentration were removed.

Biodegradation in river water was investigated in a simulation experiment. Test filter experiments were carried out in darkness under stable aerobic conditions by circulating water through a glass column filled with pumice. Based on the degradation parameters determined, o-toluidine was classified as biodegradable under the given conditions. Further, in mineral salts medium with and without (NH4)2SO4, complete removal of o-toluidine was achieved after 2 days and after 4 days, respectively. A Gram-positive bacterium (Rhodococcus rhodochrous) with the ability to utilize o-toluidine as sole source of carbon and nitrogen was isolated from soil.

Under anaerobic conditions o-toluidine could not be removed after a period of 10 month in an aquifer slurry. o-Toluidine revealed no biotic transformation, neither under sulfate reducing nor under methanogenic conditions.

In a further test o-toluidine could not be removed after 150 days in a landfill environment under anaerobic conditions. The test was not performed according to current standard methods but indicates that the substance is stable under anaerobic terms.