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

PBT assessment

PBT assessment: overall result

Reference

Name:

MDI-CHA-ODA

Type of composition:

legal entity composition of the substance

State / form:

solid: particulate/powder

Reference substance:

MDI-CHA-ODA

Reference substance:

MDI-CHA-ODA

Reference substance:

MDI-CHA-ODA

PBT status:

the substance is not PBT / vPvB

Justification:

Although the substance is a multi-component substance, it was chosen to perform the PBT assessment on the substance as a whole. As all components are diurea compounds, the substance can be considered as a mixture of homologues.

P/vP: In a ready biodegradation study according to OECD TG 301B, a maximum of 9% biodegradation was observed. Based on these findings, the substance is assessed to be not readily biodegradable and should be considered as potentially vP (and P). As the substance is considered as not B/vB, no further degradation testing is considered.

B/vB: The weighted average logPow of the substance as a whole was calculated to be 10.4 - 18.4. For substances with a calculated logPow higher than 10, it is most probably that the aquatic BCF is lower than 2000 L/kg. Furthermore, based on the low water solubility of the test substance (< 1 mg/L by visual interpretation), together with the relatively high molecular weights of its components (448-789 g/mol) and a calculated Dmax for the smallest molecule (CAS# 58890-25-8) (OECD QSAR toolbox_see section 4.27) of 1.95 nm (i.e. average Dmaxof > 1.7 nm), it can be deemed acceptable that the bioavailability of the substance will be low. This is further substantiated by the complete absence of effects in short-term studies at all 3 trophic levels. In addition there is supporting experimental evidence of hindered uptake, as in two oral repeated dose toxicity studies no adverse effects have been observed at the highest recommended dose. Moreover, the constituents of the substance can be considered to be practically insoluble in water, as their calculated water solubilities are <=0.0019 mg/L (see expert statement on hydrolysis). Therefore, in accordance with ECHA Guidance R.11, it is concluded that there is a low likelihood of a high bioaccumulation potential and the substance is therefore considered as not B/vB.

T: In acute tests with 3 trophic levels, no effects were observed at the maximum solubility of the test substance in medium. No chronic effects were observed in a study with algae. Furthermore, the substance is not classified as carcinogen, mutagenic or toxic for reproduction (CMR) and there is no other evidence of chronic toxicity (STOT RE). However, as only one chronic study is available (algae) and no information is available on the most sensitive species, no conclusion on T can be reached.