2-Butenoic acid, 1-ethyl-2-methylpropyl ester, (2E)-

Toxicity to microorganisms

Description of key information

Preliminary data showed the test item had shown strong volatility when a stream of compressed air was passed over it. 
The calculated Henry’s law constant of 159.6 Pa.m3/mol would suggest that, following the guidance given in the OECD Draft Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures, significant losses of the test item due to volatilisation may occur under the test conditions employed in a Toxicity to Activated Sludge in a Respiration Inhibition Test, therefore making it not technically possible to conduct this study.
Alternative tests such as a nitrification inhibition test (ISO 9509:2006) are also not suitable for this test item due to its strong volatile properties as this method is only applicable to non-volatile chemicals.
The results from the toxicity control vessel in the Assessment of Ready Biodegradability Manometric Test has confirmed that the test item was not toxic to the sewage treatment micro-organisms used in the Manometric Test at 100 mg/L and the test item satisfied the 10-Day window validation criterion so the test item was considered to be biodegradable.  
Therefore based on the REACH Annex VIII Guidelines as the test item was found to be readily biodegradable it is therefore considered scientifically justifiable to omit the Toxicity to Activated Sludge in a Respiration Inhibition Test from the testing program for IFF TM 12-209.