Carbamic acid, N,N'-[1,3-phenylenebis[methyleneiminocarbonylimino(methyl-3,1-phenylene)]]bis-, di-C10-14-alkyl esters

Endpoint summary

Additional information

Because of the poor water solubility of the test substance (< 0.1 mg/l, the test item is considered to be insoluble for the purposes of classification and labelling as well as chemical safety assessment), the hydrolysis behaviour is not a crucial point for the evaluation of its environmental fate and distribution pattern. Due to the insolubility of the test item, abiotic degradation by hydrolysis is irrelevant for the assessment of its environmental fate.

All other available information indicate that the test item has a strong tendency to adsorb to surfaces, hence the test item is predominantly distributed into the soil and sediment compartments whereas it is removed from the aqueous phase. Moreover, due to its extremely low vapour pressure, the test item will not evaporate. As a consequence, if released into the environment, it can be assumed that the test item will predominantly exist in the soil and sediment compartments with extremely low mobility in terms of change of environmental compartments as well as bioavailability.

Available data on skin and eye irritation indicate that the test item, although potentially adsorbed to biological surfaces, has no biological effect and hence is not considered to be hazardous.

As can be expected from its adsorption tendency and insolubility, i.e. its non-bioavailability, the test item is not readily biodegradable. In fact it showed a degradation of only 3% in a 28 d screening test, which is considered not biodegradable under test conditions for the purposes of this chemical safety assessment.

The overall conclusion regarding the environmental fate and pathways of the test item, taking into account all available and relevant data, is that it does not pose any hazard towards the environment.

PBT AND vPvB ASSESSMENT

Since the test item is characterised by physical-chemical properties that do not allow for a routine PBT/vPvB assessment, the assessment presented here is performed as outlined in the TGD on information requirements and chemical safety assessment, chapter R.11.1.4, for substances with specific properties, e.g. Log Kow > 10 and a very high sorptivity. The present assessment uses the same stepwise approach which is strictly followed.

STEP 1: Calculated or measured Log Kow

The calculated Log Kow is > 10, as detailed in IUCLID section 4.7.

STEP 2: Assessment type to be applied

Short term toxicity data is available for algae, daphnia and fish, as detailed in IUCLID sections 6.1.1, 6.1.3, and 6.1.5. In all studies performed the LC0 (NOEC) was determined to be at least 100 mg/l. Hence, the T criterion is not fulfilled.

It can be concluded that the test item is not a PBT substance and the specific vPvB assessment is performed.

STEP 3: vPvB Assessment for substances with Log Kow > 10

Step 3a: Persistency check

The test item does not contain any ester functions. Moreover, all available data indicate that its bioavailability is extremely low and therefore its rate of biotransformation is controlled by its bioavailability. For the purposes of this assessment it is concluded that the test item has only limited tranformation potential.

Step 3b: Bioaccumulation check for substances with limited transformation potential

Substances with a Log Kow > 10 are considered to have a very low bioaccumulation potential. However, this assumption should be supported by additional information. Since no results from an animal study confirming no or low bioaccumulation are available, the average molecular diameter (Dmax aver) and the molacular weight have to be considered.

Since the test item is a UVCB substance containing various molecules with alkyl chains of different length, the average molecular diameters, as specified in the TGD on data requirements and chemical safety assessment, appendix R.11-1 annex 2, of the test item containing two C10 (component I), two C12 (component II), and two C14 alkyl chains (component III) have been determined using the Chem3D Pro software. Graphical represenations of the molecular geometries are attached.

The relevant properties of the component considered are summarised in the following table:

Parameter	Component I	Component II	Component III
Mol formula	C46H68N6O6	C50H76N6O6	C54H84N6O6
Mol weight [g/mol]	801.1	857.2	913.3
Dmax aver [nm]	3.75	3.66	4.33
Water solubility [mg/l]	< 0.1	< 0.1	< 0.1
Low Kow (calculated)	12.1	14.1	16.1
Ready biodegradable	No	No	No
T criteria fulfilled	No	No	No

The additional criteria mentioned in the TGD on information requirements and chemical safety assessment, chapter R.11.1.4,

are: (i) Results from animal studiy (mammalian or fish) confirming no or low bioaccumulation (ii) Dmax aver > 1.7 nm and molecular weight > 700 g/mol. The TGD states that if for a substance with Log Kow > 10 at least one additional criterion is fulfilled, the substance should not be considered as vPvB. As can bee seen from the table, all components considered do fulfill the second criterion regarding molecular size and weight.

STEP 4: Overall conclusion

The test item is not readily biodegradable due to its very low (bio)availability. However, additional information support the low bioaccumulation potential based on the Log Kow > 10. The molecular weight and the size critera for low bioaccumulation potential are fulfilled.

Based on the available information with respect to the bioaccumulation potential, it can be concluded in a weight of evidence approach that the test item is not a vPvB substance.