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EC number: 232-092-5
CAS number: 7786-17-6
The registered substance is expected to not be biodegradable based on a weight of evidence provided on four structural analogues.
The biodegradation of the registered substance,
2,2'-methylenebis(6-nonyl-p-cresol), has been addressed using a weight
of evidence approach using data on several structural analogues. Read
across to the three substances listed below is considered appropriate
based on their structural similarities to the registered substance.
2,6-di-tert-butyl-p-cresol (CAS No. 128-37-0)
Inui (1979) determined the ready biodegradability of the test material
in a study conducted broadly in accordance with the CO2 evolution test
outlined as OECD guideline 301 B. The study was performed to sound
scientific principles with a sufficient level of detail; accordingly the
study was assigned a reliability score of 2 in line with the principles
for assessing data quality as defined by Klimisch (1997). Two
radiolabelled compounds were utilised and the test material was assessed
at several concentrations, together with different concentrations of
activated sludge, both with and without ethanol. The test material was
biodegraded by activated sludge with evolution of radioactive CO2,
evidencing a half life of 3 - 7 days (26 - 50 % of the applied
radiocarbon over 35 - 112 days). The degree of decomposition was
dependent upon the test material load, concentrations of the applied
test material, concentrations of the applied inoculated activated sludge
and the duration of incubation. Under the conditions of this study, the
test material was shown to be biodegradable.
Anon. (1978) determined the potential of the test material to undergo
biodegradation in accordance with the “Biodegradation Test of Chemical
Substances” specified in the “Test Method Relating to New Chemical
Substances (Kanpogyo No.5, Yakuhatsu No.615, 49 Kikyoku No.392, July 13,
1974)” and broadly in accordance with the principles of OECD 301 C. The
study was conducted in accordance with sound scientific principles with
limited reporting, and was thus assigned a reliability score of 2 in
accordance with Klimisch (1997). Measurement of O2 consumption showed
4.5 % degradation, whereas the results of quantification by gas
chromatography showed degradation of 0.8%. Under the conditions of this
study, the test material was shown to not be readily biodegradable.
The two available studies for this read-across substance give
conflicting information regarding the biodegradability of the substance.
Since both studies were performed to a good standard in accordance with
sound scientific principles it is not possible to determine whether the
substance is biodegradable or not.
6,6'-di-tert-butyl-4,4'-butylidenedi-m-cresol (CAS No. 85-60-9)
Saeger (1980) determined the biodegradation of the test material,
assessed as part of a screening study performed on eleven rubber
chemical products, using the shake flask carbon dioxide evolution
procedure. The study was based upon the ASTM Proposed Standard Practice
for the Determination of the Ultimate Biodegradability of Organic
Chemicals, Draft No. 3, ASTM E35.24 Subcommittee, Aquatic
Biotransformation Task Group, 2/80. The study was conducted to sound
scientific principles with limited reporting, and was assigned a
reliability score of 2 in line with Klimisch (1997). The test was
carried out over 35 days using a medium derived from soil, raw sewage
and activated sludge mixed liquor. The inoculum was exposed to the test
material in triplicate at 20.7 mg/L under aerobic conditions. At the end
of the test, 1 % biodegradation was seen (variability range 0 - 5 %).
Under the conditions of the study, the test material was determined to
not be biodegradable.
6,6'-di-tert-butyl-4,4'-thiodi-m-cresol (CAS No. 96-69-5)
Saeger (1978) determined the inherent biodegradability of the test
material by investigating primary and ultimate degradation. The primary
biodegradation of the test material was determined in a semi-continuous
activated sludge test (SCAS), whereas the ultimate biodegradation was
investigated in a Thompson-Duthie-Sturm procedure. The study was
conducted in accordance with generally accepted scientific principles,
with incomplete reporting or methodological deficiencies, which do not
affect the quality of the relevant results. Accordingly the study was
assigned a reliability score of 2 in line with Klimisch (1997). In the
SCAS test, a mean biodegradation rate of 11 ± 7 % was obtained at the 3
mg/L feed level during a 13 week test, indicating this material to be
resistant to biodegradation. In the Thompson-Duthie-Sturm procedure, no
CO2 was evolved indicating that no biodegradation took place.
Under the conditions of this study, the test material was determined to
not be inherently biodegradable.
The overall consensus of the available data is that the registered
substance is expected not to biodegrade in the environment.
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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