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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

2,4,4-trimethylpe The results of the Biowin and BioHCwin for 2,4,4-trimenthylpentene indicate that it is expected to biodegrade rapidly, with a half-life of 6.7589 days.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

The use of a QSAR to predict the biodegradability of the substance is an appropriate technique as these substances clearly fall within the applicability domain of the model, with all substructures included in the model. The results indicate that the substance is expected to biodegrade rapidly, with a half life of 6.7589 days.

The use of QSAR estimates to predict the biodegradability of hydrocarbons because they are included in the training sets of the BIOWIN and BioHC models.The databases were created using experimental biodegradation data for compounds found in crude oil and its products, with biodegradation references obtained for each of these compounds, mainly from the BIOLOG and DATALOG files of EFDB, TOXLINE and American Chemical Society Chemical Abstracts as well as literature searches. For the BioHC model, a single recommended biodegradation half-life was chosen for use in the regression analysis from the primary biodegradation data that were compiled for each hydrocarbon structure.

The supporting studies by Hydrotox (2004) and Wildlife International (2006) are GLP compliant and follow standard guidelines. They both support the characterisation of 2,4,4 -trimethylpentene as not readily biodegradable. In the EU RAR (2008), it is concluded that, based on the available information a sound assessment of biodegradation is not possible, so as a worst-case 2,4,4-trimethylpentene has to be assessed as not biodegradable. The data are supported by the results from the QSAR estimations using the BIOWINand BioHC models.

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