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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

A member of this category (CAS 97280-83-6) was shown to be readily biodegradable. 93.9% was degraded after 28 days. Estimated data using the model BioHcWin predicts that the half lives of the butylene oligomers indicates that they are readily biodegradable

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

A screening assessment for the potential persistence of the butylene oligomers was conducted using QSAR estimates of biodegradability predicted by the model Biowin. Representative structures of C8, C12 and C16 olefins were used in the assessment. The butylene oligomers are primarily within this carbon range and so use of these structures is considered representative of the category. Predicted data indicate that representative structures of this category are not considered to be readily biodegradable. This information is supported by data from a MITI (1986) study which indicated that triisobuylene was not readily biodegradable. Limited information was available on this study

However, estimations of half life generated using the BioHCwin predictive model, which has been developed specifically for hydrocarbons indicates that the half lives of the representative structures for the C8 to C16 olefins would range from 6.56 to 29.57 days respectively. Based on these predicted half lives the members of the category would not meet the criteria for persistent (P) or very persistent (vP). As the BioHCwin is specifically intended for hydrocarbons and considers a fragment based approach to estimate the biodegradation of larger hydrocarbons, this model will give a more appropriate predication for biodegradation for the butylene oligomers. A supporting study measuring the biodegradation of 97280 -83 -6 reported 93 % of the substance degraded within 28 days, indicating that the stream is readily biodegradable.

A GLP compliant, guideline study (Evonik Oxeno 2009) showed dodecene to be readily biodegradable. 93.9% was degraded after 28 days.

This data will be read across to other members of the category. This study supports the estimate of the ready biodegradation of the category and can be used to read across to the other category members.