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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

The substance does not significantly accumulate in organisms

Key value for chemical safety assessment

Additional information

For the assessment of bioaccumulation of isobutyl vinyl ether a weight of evidence approach was applied using data from model calculations as well as testing data on toxicokinetic and logPow. The logPow was measured according to OECD guideline 107 resulting in a value of 3.07 (BASF 1988, see chapter 1.3, table 4)). Using different model calculation tools reveals a calculated BCF <100 (BCFBAF v3.01; VEGA BCF Read-Across v1.1.0; BASF SE 2016). In the first study regarding toxicokinetic of isobutyl vinyl ether the stability of the test substance in gastric acid simulans and rat liver microsomes was investigates (BASF 2006) while in the second study, performed according to Practical Guide N. 1, the hydrolysis of isobutyl vinyl ether in three artificial body fluids was examined (BASF 1994, see chapter 5.1). From these studies the conclusion can be drawn that isobutyl vinyl ether hydrolyzes immediately and completely under acidic conditions which were established to simulate gastric acid. The metabolite isobutanol was detected in the range 92 to 110 % of the theoretical value. Furthermore, results showed that approx. 65 % of isobutyl vinyl ether is metabolized in vitro by induced rat liver microsomes within 2 hours under the conditions chosen. Isobutanol was only detected in the active microsome incubations. Furthermore, acetaldehyde was detected as product of hydrolysis. In simulated saliva and intestinal fluid with pH values of 7.5 and 9, respectively, hydrolysis also occurred but less quick than under the conditions of the simulated, acidic gastric fluid.

Due to the given information, isobutyl vinyl ether is expected to have a low potential for accumulation in organisms.

QSAR-disclaimer

In Article 13 of Regulation (EC) No 1907/2006, it is laid down that information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI (of the same Regulation) are met. Furthermore according to Article 25 of the same Regulation testing on vertebrate animals shall be undertaken only as a last resort.

 

According to Annex XI of Regulation (EC) No 1907/2006 (Q)SAR results can be used if (1) the scientific validity of the (Q)SAR model has been established, (2) the substance falls within the applicability domain of the (Q)SAR model, (3) the results are adequate for the purpose of classification and labeling and/or risk assessment and (4) adequate and reliable documentation of the applied method is provided.

 

For the assessment of IBVE (Q)SAR results were used for Bioaccumulation.The criteria listed in Annex XI of Regulation (EC) No 1907/2006 are considered to be adequately fulfilled and therefore the endpoint(s) sufficiently covered and suitable for risk assessment.

 

Therefore, and for reasons of animal welfare further experimental studies on bioaccumulation are not provided.