Benzenediamine, ar-methyl-, polymer with 2-methyloxirane and oxirane

Endpoint summary

Description of key information

Benzenediamine, ar-methyl-, polymer with methyloxirane and oxirane:

• will be rapidly degraded by photochemical processes after evaporation or exposure to the air.


• is hydrolytically stable.


• is not readily biodegradable (by OECD criteria).


• does not form metabolites fulfilling PBT criteria.


• does not significantly accumulate in organisms.


• is expected to adsorp to the solid soil phase.

 

Additional information

Phototransformation in air
Estimated half-lives for the components of this UVCB substance range from1.0 (higest molecular homolgue) to 1.8 hours (lowest molecular homologue) (West, 2010).

Hydrolysis
The hydrolysis behaviour of Benzenediamine, ar-methyl-, polymer with 2-methyloxirane and oxirane was investigated at pH = 4, 7 and 9 using a HPLC/MS methods for analysis. The registration item, as an NLP, contains different molecular weight fractions (= NLP-fraction) which behave similar in hydrolysis reaction. Benzenediamine, ar-methyl-, polymer with 2-methyloxirane and oxirane is found to be stable at 50°C with less than 10 % dissipation in 5 days at all three pH-values. Therefore, it can be assumed that the test item is also stable at 25°C and no half-life times and hydrolysis rates were calculated (Currenta, 2009).

Biodegradation
There is one study (Currenta, 2009) that assessed ready biodegradability within 28 days and gave a degradation of 27 % for Benzenediamine, ar-methyl-, polymer with 2-methyloxirane and oxirane. Thus, the substance is not considered to be readily biodegradable" (Currenta, 2009). Furthermore, there is a study (Currenta, 2009) that assessed inherent biodegradability within 27 days, giving a degradation of 42% for Benzenediamine, ar-methyl-, polymer with 2-methyloxirane and oxirane. Thus, the substance is, furthermore, considered to be inherently biodegradable, not fulfilling specific criteria.

Biodegradation in water, sediment and soil
Several QSAR applications have been used to assess the degradation behaviour of the registration item and, in particular, the (potential) formation of metabolites fulfilling PBT criteria.
Since Benzenediamine, ar-methyl-, polymer with methyloxirane and oxirane is a UVCB substance, there is no unique molecular structure existing. For this reason, three representative substances were defined (which cover the complete structural range of oTDA-EO-PO) and analyzed. For none of these structures and none of their relevant degradation products a PBT concern has been identified.

Bioaccumulation: aquatic / sediment
Several QSAR applications have been used to assess the potential for bioaccumulation of the registration item.
Since Benzenediamine, ar-methyl-, polymer with methyloxirane and oxirane is a UVCB substance, there is no unique molecular structure existing. For this reason, three representative substances were defined (which cover the complete structural range of oTDA-EO-PO) and analyzed.
Calculated solubilites in octanol of the three substructures range from 2.8 to 12.3 g/L and are therefore well below the "unlimited" solubility of oTDA-EO-PO in water. Although this ratio provides limited evidence, it is nevertheless a hint towards a low potential for bioaccumulation of the registration item.
All BCF models consistently predict very low potential for bioaccumulation for all three substructures used. The estimated BCF values obtained are well below 50, typically clearly below 10. There is only one single result indicating a BCF of 186 (KNN/Read-Across v1.1.0, VEGA), which may overestimate the actual potential of Benzenediamine, ar-methyl-, polymer with methyloxirane and oxirane to bioaccumulate.
It is important to note that the main mechanism identified mitigating accumulation of the registration item is metabolism. Very clearly, any component of the UVCB (potentially) taken up would be transformed and would not accumulate in e.g., fish. Furthermore, for larger substructures, size and molecular dimensions further reduce the potential for bioaccumulation.

Adsorption / desorption
The registration item was tested in an experimental study according to the OECD guideline 106 using the batch equilibrium method. The adsorption behaviour of three representative structures were particularly determined.
Log Koc values in the range of 3.46 (o-TDA-1EO-3PO at Eurosoil 2) to 5.35 (o-TDA-3EO-6PO at LUFA 2.3) were measured. For all soil types and structures a log Koc > 3 was obtained. Therefore, a strong adsorption tendency to soil is assumed for the three selected components, and therefore also for the entire UVCB.