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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

The biogradation value is 60 % after 28 days.

Key value for chemical safety assessment

Biodegradation in water:
inherently biodegradable, fulfilling specific criteria

Additional information

The evaluation of biodegradation of the substance has been based on studies conducted on the Similar Substance 01. The complete hypothesis and justification for the read across approach has been attached in section 13.

Three different tests are available to evaluate the biodegradability potential in water of the substance: one regarding the inherent biodegradability and two regarding the biochemical and/or chemical oxygen demand.

The inherent biodegradability test was carried out according to the OECD Guideline 302C. The biogradation value is 60 % after 28 days. This result is obtained at 25 ± 2 °C and in darkness.

Two studies on BOD5 and COD are available for this substance, therefore they have been used together with the previous test as supporting studies in order to exclude a rapidly biodegradation of the substance, in fact, according to the ECHA "Guidance on information requirements and chemical safety assessment - Chapter R.7b: Endpoint specific guidance" (May 2008 version 1.1), if the BOD5:COD ratio is lower than 0.5, it can be expected that the substance is not readily biodegradable; if the ratio between BOD5 and COD is more than 0.5 there is an indication of ready biodegradation.

In the first one, COD was measured according to DIN 38409 - H 41-1 method (1980) corresponding to EEC Directive 92 / 69 / C.6. (1992). The value found is 1289 mg O2/g; it is of the same order of magnitude as the value reported in the study of 1977.

In the second one, BOD, COD and BOD/COD ratio were measured according to an internal method (details of the method have been not reported). The results obtained are:

BOD5 = 11 mg/g O2

COD = 983 mg/g O2

BOD5/COD = 0.01