4,4'-methylenediphenyldiisocyanate and 2,4'-diisocyanatodiphenylmethane and their oligomerisation reaction products with 2,2'-oxydiethanol, propane-1,2-diol and butane-1,3-diol

Long-term toxicity to aquatic invertebrates

Description of key information

MDI reacts readily with water to form predominantly insoluble and inert polyurea (Yakabe et al 1994) and therefore long-term tests are not appropriate for the derivation of PNEC values. The available chronic Daphnia magna study (OECD 211) indicated no long-term effects after 21 days exposure to 10 mg/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

10 mg/L

Additional information

The test substance is covered by the category approach of methylenediphenyl diisocyanates (MDI). Hence, data of the category substances can be used to cover this endpoint. In a semi-static study with Daphnia magna (Caspers et al, 1986) with PMDI, no long-term toxicity was observed after 21 days exposure to 10 mg/L, which was the highest concentration tested. The test was carried out according to OECD Guideline 211 and the result was corroborated by the mesocosm study where no chronic effects were seen to the zooplankton at loadings of 1000 and 10,000 mg/L.

MDI is rapidly hydrolysed in aqueous solution. However, MDI is hydrophobic and poorly soluble in water and thus the heterogeneous reaction with water or soil is less rapid. The major product of such a reaction is insoluble polyurea (Yakabe et al 1994). Therefore, the long-term toxicity value is not appropriate to derive PNEC values.