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Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Additional information

Acute toxicity to fish

The key study concerning the short-term toxicity of 2,2'-dimethyl-4,4'-methylenebis(cyclohexylamin) to fish was performed according to OECD 203 (NITE Japan 2002) with Oryzias latipes. The 96-LC50 was determined to be 22.4 mg/L, the NOEC was 16 mg/L and the LC100 was 30 mg/L. These values are used for the assessment as Oryzias latipes was the most sensitive species to the substance.

The result is supported by a static-test study according to German industrial standard (DIN) 38412/15 (BASF 1988) performed with Leuciscus idus as test species. A 96-h LC50 of 31.6 mg/l was determined for non-neutralized samples (expressed as geometrical mean). The NOEC was determined to be 21.5 mg/l and the LC100 46.4 mg/l. Because DMD changes the pH in water, a neutralized sample with the highest test concentration (100 mg/l) was tested in addition. For this neutralized sample a diminution of the toxic effects was observed.

In addition, the result of the key study is supported by an acute toxicity test according to OECD 203, which was performed with Oryzas latipes in preparation of a bioaccumulation study (see also chapter 5.3.1). The LC50 after 96 hours was determined to be 32 mg/L (NITE Japan, 2002).

 

 

Long-term toxicity to fish

The results from short-term toxicity tests on fish, Daphnia and algae demonstrate that invertebrates are the most sensitive trophic level tested. Further, a reproduction test on Daphnia magna is available. Therefore, it may be concluded that results from a long-term test in fish would not reveal a greater hazard than already determined by the available data. Therefore, and for reasons of animal welfare, a chronic test on fish is not provided.

 

 

Acute toxicity to invertebrates

In the key study (NITE Japan, 2002; NMMP/E00/2090), the acute toxicity of 2,2'-dimethyl-4,4'-methylenebis(cyclohexylamine) (CAS 6864 -37 -5) was analyzed in a static test according to the OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test). The test item concentrations were analytically verified to be stable regarding sufficient recovery (> 80%).The 48-h EC50 was determined to be 4.57 mg/L (result based on not pH-adjusted test solutions).

In a supporting study (BASF AG, 1988; 1/0330/2/88-0330/88) according to EU Method C.2, Directive 79/831/EEC, Annex V, Part C, the 48-EC50 was determined to be 15.2 mg/L. Analytical monitoring of the test solutions was not conducted in this study.

 

 

Long-term toxicity to aquatic invertebrates

To determine chronic effects of 2,2'-dimethyl-4,4'-methylenebis(cyclohexylamine) (CAS 6864 -37 -5) on aquatic invertebrates, a GLP-study according to OECD 211 (21 d-reproduction test) was performed with Daphnia magna. The test concentrations were analytically verified. The mean measured concentrations for the whole exposure period were within ±20% of the nominal concentration. The NOEC was determined to be 4.0 mg/L (reproduction; nominal) (NITE Japan, 2003; NMMP/E00/3090). All validity criteria were fulfilled in this study. Based on the NOEC of 4.0 mg/L chronic effects on aquatic invertebrates are not expected.

 

 

Toxicity to aquatic algae

In a non-GLP study according to OECD Guideline 201, conducted with Desmodesmus subspicatus (BASF AG, 1989), the 72-h ErC50 was determined to be >5.0 mg/L (nominal; analytically not verified; 72-h ErC10 = 1.25 mg/L).

 

In an additional GLP-study (NITE Japan, 2002), performed according to OECD 201 (Alga, Growth Inhibition Test) with Pseudokirchneriella subcapitata, the test concentrations were analytically verified. The results were recalculated with Toxrat v2.10; the mean measured concentrations for the relevant concentration were within ±20% of the nominal values. As analytical monitoring was only performed for the study by NITE (2002), these values are selected as key data.The 72-h ErC50 was estimated to be 7.9 mg/L. The 72-h ErC10 was determined to be 4.1 mg/L and the 72-h NOEC was 0.13 mg/L. All validity criteria were fulfilled in this study.

According to the Guidance on information and safety assessment Chapter R.10: Characterisation of dose [concentration]-response for environment “an EC10 for a long-term test which is obtained using an appropriate statistical method (usually regression analysis) will be used preferentially. […] There has been a recommendation within OECD in 1996 to phase out the use of NOEC, in particular as it can correspond to large and potentially biologically important magnitudes of effect. The advantage of regression method for the estimation of ECx is that information from the whole concentration-effect relationship is taken into account and that confidence intervals can be calculated. These methods result in an ECx, where x is a low effect percentile (e.g. 5-20%). It makes results from different experiments more comparable than NOECS”

Therefore, the ErC10 (4.1 mg/L; 95% CL: 3.5 - 4.7 mg/L) instead of the NOEC has been used for the assessment. 

 

 

Toxicity to microorganisms

As key study a short-term respiration inhibition according to ISO 8192 and performed by BASF with domestic activated sludge (1990) was identified.After 30 minutes an EC20 of 160 mg/l was measured.