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Short-term toxicity to fish

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Description of key information

The test substance is covered by the category approach of methylenediphenyl diisocyanates (MDI). The read-across category justification document is attached in IUCLID section 13.


The toxicity of the substances of the MDI category to fish has been determined on the basis of current OECD 203 guideline studies on the three boucutendary/source substances and representative substances of the category. Acute fish tests are available for the following substances of the category:


4,4-MDI, pMDI, mixed isomers MDI/PIR, 4,4-MDI/1,3-BG/TPG/PG, 4,4-MDI/DPG, 4,4-MDI/TPG and 4,4-MDI/DPG/HMWP


The data show that all LL50 values obtained for all the tested substances of the category are greater than 100 mg/L. The substances of the MDI category are therefore considered as not acutely harmful to fish.


More specifically, the potential aquatic toxicity of the tested substances of the category was determined from exposures to a water accommodated fraction (WAF), as recommended in the OECD Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures (OECD, 2019).  These data are also supported by testing of a 4,4’-MDI/DPG/HMWP - monomer-depleted substance from which the monomeric MDI constituent was removed (by vacuum distillation) which showed a 96-hour LL50 value of greater than 100 mg/L (Neuhahn and West, 2020) (robust study summary added to the 4,4’-MDI/DPG/HMWP iuclid dossier). This result provides evidence that the non-monomeric MDI constituents do not contribute to the acute aquatic toxicity.


These studies have been supplemented by recently performed short-term fish toxicity studies (according to guideline OECD 203) on the (transient) transformation compounds, i.e. 4,4’-MDI and 4,4’-MDA mono-urea (Chapter 2.2.2 of the Category Justification Document) (Neuhahn, 2019) (robust study summaries added to the 4,4'-MDI iuclid dossier). Both compounds did not show toxic effects against fish (LL50 and EC50 values above 100 mg/L respectively). The available data are reliable and therefore adequate for classification and risk assessment purposes. Additional testing is not suggested.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish
Dose descriptor:
LC50
Remarks:
Values are expressed in Loading Rate (LR or LL50)
Effect concentration:
> 100 mg/L

Additional information

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