o-TOLUIDINE CAS N°: 95-53-4 - UNEP Chemicals

OECD SIDS o-TOLUIDINE
The distribution coefficient of o-toluidine between aqueous solutions and air was calculated using
the Bond-method. The HLC was 0.21 Pa m 3 /mol at 25 °C. The Group method leads to a Henry´s
law constant of 0.24 Pa m 3 /mol (Bayer AG, 2003). Using the characteristic vapour pressure and
solubility of o-toluidine at 25 °C from Table 1 (see also Table 4), and applying the HLC formula
(vapour pressure/water solubility) a Henry´s law constant of 0.25 Pa m 3 /mol is obtained.
These data indicate that o-toluidine has a low to moderate potential for volatilisation from aqueous
solutions according to the scheme of Thomas (1990).
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Table 5 Distribution in water-air (IUCLID 3.3.2)
Parameter Method Result Source
Henry´s law constant Thermodynamic method 0.2 Pa m 3 /mol Altschuh et al.,
1999
Henry´s law constant Calculated with
HENRYWIN, v. 3.10
(Bond-method)
Henry´s law constant Calculated with
HENRYWIN, v. 3.10
(Group-method)
Henry´s law constant ratio between vapour
pressure and water
solubility
2.2.5 Biodegradation
UNEP PUBLICATIONS
0.21 Pa m 3 /mol Bayer AG, 2003
0.24 Pa m 3 /mol Bayer AG, 2003
0.25 Pa m 3 /mol Bayer AG, 2003
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.
An aerobic ready test was performed according to the national Japanese standard method
comparable to the OECD TG 301 C guideline. After a period of 28 days 65.4 % biodegradation was
observed (MITI, 1992). No information is given in relation to the 10 d-window.
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 (Brown and Laboureur, 1983). In all cases the 10 d-window criterion was
fulfilled.
Results on the inherent biodegradability of o-toluidine are also available.
A test on inherent biodegradability was conducted by Pitter (1976). 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.