Reaction product of 4,4'-methylenediphenyl diisocyanate (MDI) (101-68-8), Octylamine (111-86-4) and Cyclohexylamine (108-91-8)

Endpoint summary

Description of key information

Aquatic toxicity endpoints are based on test data following standard guidelines. All data are therefore considered to be reliable and relevant for the endpoint concerned.

 

Short-term toxicity to fish

  

Acute toxicity to fish has been assessed for four substances that would fall within the MDI category definition: a mixture of: 3,3'-dicyclohexyl-1,1'-methylenebis(4,1-phenylene)diurea; 3-cyclohexyl-1-(4-(4-(3-octadecylureido) benzyl)phenyl)urea; 3,3'-dioctadecyl-1,1'-methylenebis(4,1-phenylene)diurea (EC 406-530-2), 3,3'-dicyclohexyl-1,1'-methylenebis(4,1-phenylene)diurea (EC 406-370-3), 3,3'-dioctadecyl-1,1'-methylenebis (4,1-phenylene)diurea (EC 406-690-3). All studies used water accommodated fractions or saturated solutions as the test items are poorly soluble UVCBs and all determined LC50 values greater than the limit of solubility, with NOEC values equal to the limit of solubility. Based on these results, members of the MDI category are not expected to be acutely toxic to fish at the limit of solubility.

No data are available on the chronic toxicity to fish.

 

Short-term toxicity to aquatic invertebrates

  

Acute toxicity to Daphnia magna has been assessed for four substances that would fall within the MDI category definition: a mixture of: 3,3'-dicyclohexyl-1,1'-methylenebis(4,1-phenylene)diurea; 3-cyclohexyl-1-(4-(4-(3- octadecylureido)benzyl)phenyl)urea; 3,3'-dioctadecyl-1,1'-methylenebis(4,1-phenylene)diurea (EC 406-530-2), 3,3'-dicyclohexyl-1,1'-methylenebis(4,1-phenylene)diurea (EC 406-370-3), 3,3'-dioctadecyl-1,1'-methylenebis (4,1-phenylene)diurea (EC 406-690-3) and N,N''-(methylenedi-4,1-phenylene)bis[N'-octyl]urea (EC 445-760-8). All studies used water accommodated fractions or saturated solutions as the test items are poorly soluble UVCBs and all determined EC50 values greater than the limit of solubility, with NOEC values equal to the limit of solubility. Based on these results, members of the MDI category are not expected to be acutely toxic to aquatic invertebrates at the limit of solubility.

 

Long-term toxicity to aquatic invertebrates

  

Chronic toxicity to Daphnia magna has been assessed for one substance that would fall within the MDI category definition: Reaction product of 4,4’-methylenediphenyl diisocyanate and amines, coco alkyl. A Daphnia reproduction study conducted according to OECD guideline 211 was carried out using a water accommodated fraction at a single nominal loading rate of 100 mg/L, as the test item is a poorly soluble UVCB. The determined EL50 values, based on parental mortality and reproduction, were >100 mg/L, with a NOELR value of 100 mg/L, the only concentration tested. Based on these results, members of the MDI category are not expected to be chronically toxic to aquatic invertebrates at the limit of solubility.

 

Toxicity to aquatic algae and cyanobacteria

  

The effects of two MDI category members on the growth of Pseudokirchneriella subcapitata and Desmodesmus subspicatus, respectively, were investigated in separate studies. The study of Veryenhoef (2018) used a water accommodated fraction and determined EL50 values of >100 mg/L, with NOELR values of 100 mg/L, for both growth rate and yield, for the test item Reaction product of 4,4’-methylenediphenyl diisocyanate and amines, coco alkyl. For the study conducted with 3,3'-dicyclohexyl-1,1'-methylenebis(4,1-phenylene)diurea (EC 406-370-3), used as a supporting study, the derived EC50 and NOEC values based on growth rate and yield are > 1 mg/L, the highest concentration tested. 

One study conducted with N,N''-(methylenedi-4,1-phenylene)bis[N'-octyl]urea (EC 445-760-8), did show effects below the highest concentration tested. This study was included in a NONS registration and permission to refer has been granted by ECHA under an Article 25(3) request. A limited summary was provided in the data received from ECHA. Reference to the same study on the ECHA dissemination portal indicates that the study has subsequently been disregarded by the registrants as the study used very high nominal loading rates (up to 4000 mg/L) and only analysed for one constituent of the substance, which was found to be in solution at <LOQ (0.5 mg/L). As the analysed constituent was present at <LOQ but a dose-response relationship was observed at the highest loading rates, toxicity appears to be attributed to an unknown impurity in the test item. As it is not possible to determine which constituent the observed toxicity is attributed to, the water solubility of the main constituent should not be used for the reporting of results, as this is not the constituent that is leading to the observed toxicity. This study has therefore been disregarded as the results are unreliable.

Based on results from the reliable studies, members of the MDI category are not expected to be toxic to algae at the limit of solubility.

 

Toxicity to microorganisms

  

Toxicity to microorganisms has been assessed for two substances that would fall within the MDI category definition. All studies were conducted following standard guidelines. All studies determined IL50 values greater than the highest nominal loading rate. Members of the MDI category are not expected to be toxic to microorganisms at the limit of solubility.