Bis(2,6-diisopropylphenyl)carbodiimide

Toxicity to soil macroorganisms except arthropods

Administrative data

Endpoint:

toxicity to soil macroorganisms except arthropods: long-term

Type of information:

experimental study planned

Study period:

The study will be placed following ECHA`s acceptance of the Testing Proposal. Depending on the capacities of the test facilities, the results should be available at the latest 6 - 12 months thereafter.

Justification for type of information:

TESTING PROPOSAL for study according to Annex X of REACH

NON-CONFIDENTIAL NAME OF SUBSTANCE:
- Name of the substance on which testing is proposed to be carried out:
Bis(2,6-diisopropylphenyl)carbodiimide (CAS 2162-74-5)

CONSIDERATIONS THAT THE GENERAL ADAPTATION POSSIBILITIES OF ANNEX XI OF THE REACH REGULATION ARE NOT ADEQUATE TO GENERATE THE NECESSARY INFORMATION:
- Available GLP studies: No data from GLP studies with terrestrial organisms available.
- Available non-GLP studies: No data from non-GLP studies with terrestrial organisms available.
- Historical human/control data: No historical human/control data for the terrestrial compartment available.
- (Q)SAR: No QSAR data for terrestrial organisms available.
- In vitro methods: Not applicable
- Weight of evidence: Not applicable
- Grouping and read-across: Not applicable

CONSIDERATIONS THAT THE SPECIFIC ADAPTATION POSSIBILITIES OF ANNEXES VI TO X (AND COLUMN 2 THEREOF) OF THE REACH REGULATION ARE NOT ADEQUATE TO GENERATE THE NECESSARY INFORMATION:
As demonstrated in the environmental exposure and risk assessment of the CSR, releases to the terrestrial environment are low – even despite the worst-case approach applied in the assessment. Nonetheless, a robust justification of “unlikely exposure” based on Col. 2 of REACH Annex IX cannot be delivered because of the insufficient documentation on downstream uses available to the registrant. It is therefore deemed as reasonable to undertake an Annex XI.3.2. (a) route based on derived PNEC. Accordingly, a study on earthworms is planned to be conducted by the lead registrant/consortium, to verify absence of risk/hazard for the terrestrial compartment.
According to Table R.7.11-1 of ECHA Endpoint specific guidance, Chapter R.7c (V 3.0, June 2017), the exposure pathway for invertebrates is by diverse uptake routes (soil pore water, ingestion of soil material, soil air, secondary poisoning). The exposure pathway for plants and microorganisms is the soil pore water, which is expected to contain a negligible amount of substance due to its poor solubility (< 0.53 μg/L (Holzaht-Grimme, 2019)). Further, the same guidance states “The choice of test (invertebrate / plant / micro-organism) would be based on all the information available, but in the absence of a clear indication of selective toxicity, an invertebrate (earthworm or collembolan) test is preferred.” (R.7c, page 149, V 3.0, June 2017).
Under Annex IX of REACH, short-term studies are standardly required, but, taking into account the substance’s high adsorptivity and potential persistence, a long-term study is deemed adequate. For the same reason, it was decided against screening based on EPM.
Hence, an Earthworm Reproduction Test according to OECD 222 with Eisenia fetida/Eisenia Andrei as representative terrestrial invertebrate is envisaged to be conducted with test concentrations being at least 10-fold higher than the regional PEC determined for the soil compartment, which is 4.54E-6 mg/kg dw as presented in Table 161 of the regional assessment within the CSR for the registered substance.
The study result will then be used to calculate the PNECsoil of the substance and, subsequently, the PEC/PNEC ratio. Should it be <<1, “no significant exposure” will be deemed proven. Otherwise, further testing will be considered.

FURTHER INFORMATION ON TESTING PROPOSAL IN ADDITION TO INFORMATION PROVIDED IN THE MATERIALS AND METHODS SECTION:
- Details on study design / methodology proposed:
As outlined above an Earthworm Reproduction Test according to OECD 222 is envisaged to be conducted with the earthworm Eisenia fetida/Eisenia andrei as test organism. Following the recommendations of the Endpoint specific Guidance Version 3.0, Chapter R.7c of June 2017, the study will be conducted with test concentrations being at least 10-fold higher than the PEC soil determined for the regional assessment and based on the total releases to the soil compartment.
Due to the poor solubility of the registered substance, it will probably be necessary to apply the test material by the use of a suitable vehicle, which can be completely evaporated before the exposed soil can be used for the test performance. Therefore, respective pre-experiments will be conducted ahead to determine the most meaningful test design for the performance of the definitive test. If it is demonstrated to be sufficient by the results of the pre-experiments, the definite study will be performed as limit test only.

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 222 (Earthworm Reproduction Test (Eisenia fetida/Eisenia andrei))

Test material

Test material information

Constituent 1

Reference substance name:

Bis(2,6-diisopropylphenyl)carbodiimide

EC Number:

218-487-5

EC Name:

Bis(2,6-diisopropylphenyl)carbodiimide

Cas Number:

2162-74-5

Molecular formula:

C25H34N2

IUPAC Name:

N,N'-bis[2,6-bis(propan-2-yl)phenyl]methanediimine

Test material form:

solid