Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 202-200-5
CAS number: 92-88-6
The ready biodegradability of biphenyl-4,4'-diol was determined with a
non-adapted inoculum according to the CO2 Evolution Test (OECD 301B).
The test item concentration was deliberately lowered below the range
indicated in the guideline because the test item was considered capable
of inhibiting the activity of the microbial inoculum and hence limiting
the outcome of the test. The study was performed in two stages: an
initial, non-GLP preliminary test was first used to establish the
viability of the test conditions before conducting the main, fully
GLP-compliant definitive test. Extensive biodegradation of
biphenyl-4,4'-diol (with CO2 production >60% of the theoretical yield -
the threshold that conventionally represents complete mineralisation)
was observed in at least one replicate test vessel of the CO2 Evolution
Test in both the preliminary and definitive stages.
In both the preliminary and definitive stages, the initial test based on
measurement of CO2 production was followed by a further, confirmatory
test that employed different methodology based on the measurement of
cumulative oxygen uptake. For this purpose, adapted sludge was harvested
at the end of the incubation from one or more of the replicate test
vessels of the CO2 Evolution Test incubation where >60% theoretical CO2
production had occurred and was used to inoculate a confirmatory
assessment performed according to the Manometric Respirometry Test (OECD
301F), with a higher concentration of the test item. In each case,
complete biodegradation occurred in all replicates of the respirometric
test based on oxygen uptake, confirming the outcome of the earlier phase
that relied on CO2 yield measurements.
Biphenyl-4,4'-diol degraded erratically in the presence of unadapted
microorganisms in the CO2 Evolution Tests of both the preliminary and
definitive test stages. Degradation was sufficient in some replicates to
indicate complete mineralisation and meet the 'pass' level for
classification as readily biodegradable, but not in others. The length
of the lag phase between test initiation and the onset of significant
degradation was highly variable and in some replicates of the definitive
test the rapid degradation phase was not observed at all despite
extending the incubation to 60 days. In view of its erratic performance
in relation to the pass criteria and the divergence permitted between
replicates at test-end or plateau, biphenyl-4,4'-diol does not qualify
for classification as readily biodegradable. Nevertheless,
biphenyl-4,4'-diol has exhibited a potential to undergo rapid and
ultimate biodegradation (i.e. complete mineralisation) and this finding
in the CO2 Evolution Test was confirmed by further tests performed
according to the Manometric Respirometry Test, using an inoculum
pre-adapted in the earlier testing phase.
Biphenyl-4,4'-diol is non-persistent (not P).
As biphenyl-4,4'-diol does not qualify for classification as readily
biodegradable, it is classified as "inherently biodegradable, not
fulfilling specific criteria" (no specific inherent biodegradability
tests have been performed) for the purposes of predicting concentrations
of biphenyl-4,4'-diol that may enter the aquatic compartment via
The consistently high level of degradation achieved with an adapted
inoculum is relevant to situations where waste-waters and process
effluents containing biphenyl-4,4'-diol are likely to pass through
dedicated industrial STPs before reaching the aquatic environment.
Biphenyl-4,4'-diol is classified as "rapidly biodegradable" for CLP
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.
Welcome to the ECHA website. This site is not fully supported in Internet Explorer 7 (and earlier versions). Please upgrade your Internet Explorer to a newer version.
Do not show this message again