4,4'-methylenebis[N-sec-butylaniline]

Biodegradation in soil

Administrative data

Endpoint:

biodegradation in soil: simulation testing

Type of information:

experimental study planned

Study period:

As soon as testing proposal is agreed upon by ECHA

Justification for type of information:

TESTING PROPOSAL FOR OECD 307 WITH 4,4’-methylenebis-N-sec-butylaniline (MDBA)
In order to come to an unequivocal conclusion on the PBT properties of the substance, further information is needed. MDBA has a partitioning coefficient (Log Kow) of 5.4. In order to determine the Bioaccumulative properties of the substance, a bioconcentration study was conducted. Based on the results collected in the present study, the test item is considered to be bioaccumulative in fish at a nominal exposure concentration of 0.6 μg/L and very bioaccumulative at a nominal exposure concentration of 6 μg/L when considering total radioactive residue concentrations. When considering parent related radioactive residue concentrations, uptake in fish tissue was still significant but formed on average about 40-50% of the total radioactive residue concentrations. Therefore it can be concluded that the substance MDBA is very Bioaccumulative (vB). The substance is T, since the substance is classified as STOT RE category 2 based on an OECD 422 study.
The ready biodegradation study revealed that the substance is not readily biodegradable and therefore potentially P or vP. Further testing is necessary to come to an unequivocal conclusion on the persistence properties of the substance.

SELECTION OF THE RELEVANT ENVIRONMENTAL COMPARTMENT:

1.Testing in the sediment and/or soil compartments should be considered in particular if there is a specific concern for this compartment, for example, if direct or indirect releases to these compartments are likely, or if the substance is predicted to accumulate in these compartments. Koc or Kd values can be used as an indicator of whether the substance is likely to be of concern for the sediment and soil compartments. As a rule of thumb, substances with log Koc > 4 are generally regarded as highly adsorptive and likely to distribute in sediment and soil. Since the log Koc of 4,4’-methylenebis-N-sec-butylaniline (MDBA) is 5.19, there is a specific concern for the soil and sediment compartment.

2. Since MDBA is likely to break down into the ‘backbone’ structure of the starting material, it can be assumed that based on this information, this substance will have similar persistence properties as the starting material 4,4’-methylenedianiline (EC 202-974-4) and therefore information from 4,4’-methylenedianiline can be used as a starting point for 4,4’-methylenebis-N-sec-butylaniline (MDBA).
According to the disseminated dossier of the starting material 4,4’-methylenedianiline (EC 202-974-4), this substance is considered Persistent in the environment (P, not vP): “Although simulation tests in water and sediment indicate that the substance is not persistent in these environmental media, data from soil degradation tests under aerobic and anaerobic conditions lead to the assumption, that the substance might be persistent (P) but not very persistent (not vP) in soil. At the beginning of the test biodegradation occurs while at a later stage no biodegradation occurs. This is likely due to binding to organic soil matter e. g. humic acids. Hence, the substance is not bioavailable for degradation anymore."

Since the simulation tests in water and sediment indicate that the starting material 4,4’-methylenedianiline (EC 202-974-4) is not persistent in these environmental media and in soil it might be persistent, further investigation of the persistence properties of 4,4’-methylenebis-N-sec-butylaniline (MDBA) by performing the OECD 307 study is considered as the most likely route to an unequivocal outcome of the PBT assessment.

NON-CONFIDENTIAL NAME OF SUBSTANCE:
- Name of the substance on which testing is proposed to be carried out: 4,4'-methylenebis-N-sec-butylaniline (MDBA)

CONSIDERATIONS THAT THE GENERAL ADAPTATION POSSIBILITIES OF ANNEX XI OF THE REACH REGULATION ARE NOT ADEQUATE TO GENERATE THE NECESSARY INFORMATION:
- Available GLP studies: none available for the registered substance
- Available non-GLP studies: none available for the registered substance

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:
- The substance is not readily biodegradable

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 307 (Aerobic and Anaerobic Transformation in Soil)

Test type:

laboratory

Test material

Test material information

Constituent 1

Reference substance name:

4,4'-methylenebis[N-sec-butylaniline]

EC Number:

226-122-6

EC Name:

4,4'-methylenebis[N-sec-butylaniline]

Cas Number:

5285-60-9

Molecular formula:

C21H30N2

IUPAC Name:

4,4'-methylenebis[N-sec-butylaniline]