2,2'-dimethyl-4,4'-methylenebis(cyclohexylamine)

Endpoint summary

Description of key information

Toxicity to soil macroorganisms

Effects of Hydrogenation products of 4-[(4-amino-3-methyl-phenyl)methyl]-2-methyl-aniline (CAS 6864-37-5, DMDC) on the reproducibility of earthworms (E. fetida) were studied in a GLP guideline study following OECD 222. Based on nominal concentrations, the EC10 for effects on reproduction was 228 mg/kg soil dw (95% CL: 115.6 / 450.8) (BASF, 2013; report No. 68E0695/00G009).

Toxicity to terrestrial arthropods

A long-term study with earthworm was performed according to OECD 222 (see IUCLID Ch. 6.3.1); therefore, the trophic level of invertebrates is sufficiently covered. No further testing is performed.

Toxicity to terrestrial plants

In Annex X Section 9.4 of Regulation (EC) No 1907/2006, it is laid down that tests on terrestrial organisms shall be proposed by the registrant if the chemical safety assessment indicates the need to investigate further the effects on terrestrial organisms. According to Annex IX and X, the choice of the appropriate tests depends on the outcome of the chemical safety assessment. Since invertebrates were the most sensitive group as indicated from aquatic short-term and long-term toxicity data, a chronic earthworm study was performed to cover this endpoint in accordance with REACh guidance for compounds in soil hazard category 3 (ECHA, Guidance on Information Requirements and Chemical Safety Assessment, Version 3.0, June 2017, Chapter R.7c, Table R.7.11 -2). In addition, the toxicity to soil microorganisms was tested in a nitrogen transformation test according to OECD 216. In Annex XI Section 3, it is laid down that testing in accordance with Annex IX and Annex X may be omitted, based on the exposure scenario(s) developed in the Chemical Safety Report (“Substance-Tailored Exposure-Driven Testing”). In accordance with Annex XI Section 3, it can be demonstrated in the risk assessment that the manufacture and the use of the substance do not pose an unacceptable risk for all environmental compartments as the risk characterization ratios (RCRs) of the chemical safety assessment are below 1 for all compartments (see Chemical Safety Report Ch. 10).  Consequently, no further tests on soil organisms are performed. The PNEC was derived using the available experimental data on terrestrial toxicity.

Toxicity to soil microorganisms

A nitrogen transformation test according to OECD 216 was performed under GLP to determine the effects of the test substance to soil microorganisms (BASF SE, 2013; project no. 37G0695/00X032). Negative effects on the nitrate formation were not found, therefore no effect concentrations could be calculated. Nitrate concentration in treated soil was significantly higher than the nitrate concentration of the solvent control soil at concentrations of greater than or equal to 62.5 mg/kg soil dw on day 0 and greater than or equal to 125 mg/soil dw on day 28 of the test.

The derived NOEC is based on the increase of nitrate in soil due to additional nitrate derived from the test substance: NOEC = 62.5 mg/kg soil, negative effects were lacking at the tested concentrations. It is assumed that the increase in nitrate content was due to the amount of nitrate entering the soil via the test substance.

A 28-d EC10 greater than 1000 mg/kg will be used for the environmental risk assessment.

Long-term toxicity to birds

In Annex X, section 9.6.1 of the Regulation (EC) No 1907/2006 REACH concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH), it is suggested, that in case of long term toxicity testing to birds "any need for testing should be carefully considered taking into account the large mammalian dataset that is usually available at this tonnage level." Furthermore, ECHA (2008) states in the "Guidance on information requirements and chemical safety assessment Chapter R.7c" (R.7.10.6) that "given that mammalian toxicity is considered in detail for human health protection, the need for additional data for birds must be considered very carefully – new tests are a last resort in the data collection process." In addition, based on the low log Kow and the low measured and estimated BCF values, significant bioaccumulation in organisms is not to be expected (see IUCLID Ch. 5.3.1).  Hence, secondary poisoning is of no concern. Taking this into account, long-term or reproductive toxicity tests on birds do not need to be conducted due to the facts that a mammalian dataset is available.