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EC number: 200-814-8
CAS number: 74-84-0
In the study with just marine water, ethane, propane and isobutane showed evidence of degradation with half-lives of 7 to 33 days. In the study with marine water and sediment, propane, butane and isobutane showed evidence of degradation from test initiation, with half-lives of 18 to 139 days but, after a lag-phase of approximtaely 2 weeks, the substances were degraded completely within about 3 days.
accordance with column 1 of REACH Annex IX, this study does not need to
be conducted as the streams wtihin the category have a low potential for
adsorption to sediment. In addition column 2 Annex IX and column 2 Annex
X is also applicable as simulation testing does not need to be conducted
if CSA according to Annex I has not indicated a need to investigate
further the degradation of the substance in water.
data are available on the persistence of the substances in marine water
and marine water and sediment systems. Gas exchange-biodegradation
experiments conducted in model estuarine ecosystem shows that members of
the category are not expected to be persistent. The study is a non-GLP,
non-guideline study but is well described and is considered suitable for
use for this endpoint.
study with just marine water, ethane, propane and isobutane showed
evidence of degradation with half-times of 7 to 33 days. Samples from
later in the experiment showed much more rapid biodegradation, which the
authors interpret as resulting from adjustment of the bacterial
populations to the availability of the substances. Although results of
>70 days were given for the half-life of methane in marine water, the
authors report that the loss of methane could be accounted for by gas
exchange. Therefore, results for methane have not been included in the
REACH dossier as they do not represent actual degradation of the
study with marine water and sediment, propane, butane and isobutane
showed evidence of degradation from test initiation, with half-lives of
18 to 139 days. The slower rates of degradation compared to experiment 1
are thought to result from the lower temperature (10°C as opposed to
20°C). A lag-time of approximately 2 weeks was seen for the bacteria in
the tank to respond completely to the availability of the gases and
develop a population with a strong hydrocarbon utilisation capability.
Between 311 and 400 hours, ethane, propane, butane and isobutane showed
rapid decreases in concentration, far in excess of earlier degradation,
gas exchange and outflow. Ethane, which was degraded completely in about
3 days, was the slowest of the substances. Methane also appeared to be
degraded during this period, at a rate of about 2.9% per day,
corresponding to a half-life of about 24 days.
propane, butane and isobutane are subject to degradation in marine
ecosystems on the timescale of a few days to a few weeks. Initial rates
of degradation are significantly slower than the predicted loss by gas
exchange from typical natural estuaries. After a period of 15 to 30 days
of moderate degradation, bacterial populations can adjust and degrade
gaseous hydrocarbons at least an order to magnitude more rapidly. Thus,
for chronic inputs to estuaries, degradation could become the dominant
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.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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