3,3'-methylenebis[5-methyloxazolidine]

Long-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

fish early-life stage toxicity

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Description of key information

There is no test available on the chronic toxicity to fish using the substance. However, the available data on acute toxicity indicate that fish is the trophic level with the lowest sensitivity, as the LC50 (57.7 and 71 mg/L, Danio rerio) are much higher compared to the ErC50 (3.20 and  2.6 mg/L) of the algae (Desmodesmus subspicatus). In addition, the comparison of the acute EC50 value for Daphnia magna (28 and 37.9 mg/L) and the NOEC of the Daphnia reproduction test (1.3 mg/L) reveals that the acute-chronic ratio (ACR) is significantly lower than factor 100 (AF 10 for LC50 -> NOEC and AF 10 
for acute -> chronic). Although specific negative effects of the substance (reaction product) on Daphnia reproduction have been observed, the ACR is not  unexpected high. Based on these findings, it can be assumed that the substance does not cause high specific negative effects on fish reproduction.
Overall, it is unlikely that another chronic NOEC from fish would be lower. Than the NOEC available for the most sensitive taxonomic groups – algae and invertebrates. Furthermore, testing of such species would be ethically questionable and contrary to animal welfare concerns.
Therefore, a test on chronic fish toxicity is scientifically not justified.

Additional information

In addition, in aqueous media the constituents of the substance are rapidly hydrolysed (DT50 < 1 hour). At a concentration of 0.0025% (equally to 25 mg/L) the hydrolysis equilibrium is nearly complete at the hydrolysis products formaldehyde and 2-hydroxypropylamine (HPA). Therefore, in the concentration range applied in ecotoxicity tests the reaction product is completely or nearly completely hydrolysed, and thus, observed effects are caused by the hydrolysis products.

The comparison of aquatic toxicity data for the substance and its hydrolysis products reveals clearly that the toxicity of the substance is exclusively determined by its formaldehyde content.