Registration Dossier
Registration Dossier
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EC number: 270-732-5 | CAS number: 68477-42-9 A complex combination of hydrocarbons obtained from extractive distillation of saturated and unsaturated aliphatic hydrocarbons usually ranging in carbon numbers from C3 through C5, predominantly C4. It consists of saturated and unsaturated hydrocarbons having carbon numbers predominantly in the range of C3 through C5, predominantly butenes and isobutylene.
Biodegradation in water: screening tests
Administrative data
Link to relevant study record(s)
Description of key information
The members of category C4, high 1,3 -butadiene (>0.1%) are not considered to be readily biodegradable as there is not sufficient data to indicate that they are readily biodegradable.
Key value for chemical safety assessment
Additional information
The members of category C4, high 1,3 -butadiene (>0.1%) are gases at standard temperature and pressure and therefore conducting a standard ready biodegradability test is technically difficult, and based on exposure estimates the test may not be relevant.
Measured data is available for 1,3-butadiene. An OECD TG 301D closed bottle test (MITI, 2001) on 1,3-butadiene reported 0 - 4% biodegradation over 28 days. We have been unable to obtain a copy of the original report in order to assess its reliability.
In the absence of a standard study, it is appropriate to predict the biodegradability of a number of C4 substances (butane, 2-butene and 1,3-butadiene) using a (Q)SAR model . The data generated can be used as part of a weight of evidence approach to fulfil this endpoint requirement. The use of BioHCwin is appropriate for as these compounds fall within the applicability domains of this model. Results from (Q)SAR models are generally used to confirm persistence, rather than to indicate ready biodegradation. The results from the BioHCwin model do not indicate that the streams in this category would be expected to be persistent.
Taking into account the measured data for 1,3-butadiene and the (Q)SAR available, there is not sufficient evidence to demonstrate that the streams in this category are readily biodegradable.Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
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