Butanal, reaction products with aniline

Endpoint summary

Additional information

Abiotic degradation:

Both, biotic and abiotic degradation studies show that the substance is partially degradable. In the hydrolysis study about 30% of primary degradation was observed yielding aniline as the main hydrolysis product. Similar degradation rates were observed in ready biodegradation tests assuming that aniline is formed hydrolytically in this study which is then biodegraded.

Biotic degradation:

In different tests according to OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test) and to OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test) degradation rates between 24% and 37% were observed. In conclusion butanal, reaction products with aniline is not readily biodegradable. A further test according to OECD Guideline 302 C (Inherent Biodegradability: Modified MITI Test (II)) showed 39% degradataion after 56 days.

According to section 1 of REACH annex XI, the performance of a study for Biodegradation in a water-sediment system and for biodegradation in soil are scientifically unjustified. In biodegradation test in water, biodegradation of about 30 to 40% was noticed. This percentage reflects to the part of butanal, reaction products with aniline hydrolysing rapidly to aniline. The remaining 70% were found stable under test conditions.

Bioaccumulation

Curently no study on the bioaccumulation of the substance in fish is available, and it shall be discussed whether a study is needed and feasible. Technical feasability or non-feasability is considered as follows:

1. UVCB: The substance is UVCB and consists of components which can be characterised as quasi-homologues of aniline and butanal in several molar relations. Eleven clusters of components have been characterised. However, the exact structures are not known, and several isomers of the tentatively assigned structures are possible. Additionally about 10% unidentified components are contained.

2. Instability: A portion of about 30% of the substance hydrolyses quickly at pH7 even at room temperature. At 70°C, the formation of aniline is complete after 31 minutes. One main end-product after hydrolysis and especially under photolytical conditions is formed which is tentatively 3 -ethyl-4 -propyl-quinoline.

3. Complex reactivity: A BCF test even in a flow-through system would require a stock container with the dissolved substance. Reaction of the substance is expected to occur in this container. Due to the complex reaction pattern in water where some components are hydrolysed but others are formed, it is predictable that stable conditions cannot be obtained which are required for a proper calculation of the BCF.

As a conclusion, a bioconcentration test would be technically extremely difficult or not feasable at all.