4-methyl-m-phenylene diisocyanate

Short-term toxicity to fish

Description of key information

Key study: Tadokoro 1997 (1)-(3), all of comparable quality. The 24h pre-test mixing of TDI into culture medium by magnetic stirring seems to be an acceptable compromise between "static" addition on the requirements of the OECD guidance document on difficult substances in aquatic toxicity testing.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

133 mg/L

Additional information

Results obtained in the short-term studies indicate that TDI does have low toxicity to a variety of fish. None of the authors of the studies attempted the determination of TDI at the end of the test period and it is highly probable that TDI disappeared from the media soon after addition to the water and any measured toxic effects were due to the presence of hydrolysis products. It should be noted that when TDA was formed, and measured, in several of the above studies, levels of only 4-16mg/l were detected. These levels are at least ten times lower than the 96h LC50 values of TDA (219-1420 mg/l) for fish other than Pagrus major. Caspers et al (1986) reported a markedly increased toxicity to fish ( Brachydanio rerio) when TDI was dispersed into the experimental medium by high speed shearing, going from a lowest LC100 value of 250mg/l to an LC100 of 40-50 mg/l. This effect could have been caused by an increased yield of TDA in the medium, however these data should be considered as irrelevant as such a dispersion method does not reflect situations which might occur in the environment.

Taking this into account, data generated by Tadokoro et al (1997) are regarded as most relevant for the assessment of the acute toxicity of TDI to fish.