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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

Data is not available to demonstrate that acetylene is readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

As acetylene is a gas at standard temperature and pressure conducting a standard ready biodegradability test is technically difficult and, based on exposure estimates, the test may not be relevant. An OECD 301D closed bottle test has been identified (MITI 2001) which reports 0 % biodegradation over 28 days. We have been unable to obtain a copy of the original report in order to assess its reliability.

The use of the QSARs, BioHCwin v 1.01 in EPI Suite 4 2009 (Howard et al 2005) and Biowin v 4.1 in EPI Suite 4 2009 (Howard et al 1992), to predict the biodegradability of acetylene has also been conducted as part of a weight of evidence approach to fulfil this endpoint requirement. The results taken from BioHCwin must be treated with caution as this compound falls outside the applicability domain, though the predictions suggest that acetylene does have the potential to biodegrade.

In summary, reliable data are not available to demonstrate that acetylene is readily biodegradable and, for the purposes of a risk assessment, ready biodegradability will not be assumed.