Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

In the key study (Ciba-Geigy, 1985), the ready biodegradability of the test item was assessed over a 28 day period by the modified Sturm test (OECD 301B). The nominal test concentrations were 10 and 20 mg a.s./L. The test material attained up to 42 and 46 % biodegradation after 28 days whereas the positive control substance (Aniline) was 100 % degraded 28 days. Therefore, the test substance is not readily biodegradable according to OECD criteria. It is moderately/partly biodegradable.

The Chemical Oxygen Demand of the test item was determined to be 1.86 g COD/g. The test substance was not readily biodegradable in an OECD 301B study.

Possible degradation pathway:

It should be mentioned that according to Giger et al. (2009) and Montgomery-Brown (2008) it is indicated that the test substance can be metabolized via nonylphenol. This could be an explanation for the partial biodegradation. However, the European Union Risk Assessment Report on 4-nonylphenol (branched) and nonylphenol (2002) states "The nonylphenol ethoxylates released to the environment (NP1EO, NP2EO, NPnEO, NPnEC) will undergo further degradation. The information available indicates that nonylphenol is only a minor product from the aerobic degradation of these compounds in river water (indeed often no trace of nonylphenol was seen in river die-away test etc.) and soil." NP1EC is CAS 3115-49-9 and is covered by NPnEC.

Nevertheless, it can be assumed that at least a small part of nonylphenol can be released to the environment via biodegradation of the test substance.

4-Nonylphenol, branched and linear [substances with a linear and/or branched alkyl chain with a carbon number of 9 covalently bound in position 4 to phenol, covering also UVCB- and well-defined substances which include any of the individual isomers or a combination thereof] is part of the

Candidate List of Substances of Very High Concern for Authorisation (Decision number ED/169/2012; Equivalent level of concern having probable serious effects to the environment (Article 57 f)). However, no decision is made by now.

Reference:

Walter Giger, Frédéric L. P. Gabriel, Niels Jonkers, Felix E. Wettstein and Hans-Peter E. Kohler (2009): Environmental fate of phenolic endocrine disruptors: field and laboratory studies. Phil. Trans. R. Soc. A 367, 3941 - 3963

Montgomery-BrownJ,Li Y,Ding WH,Mong GM,Campbell JA,Reinhard M. (2008):

NP1EC degradation pathways under oxic and microxic conditions.

Environ. Sci. Technol. 42 (17) :6409-14.


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