Registration Dossier

Diss Factsheets

Environmental fate & pathways

Biodegradation in water: screening tests

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Justification for type of information:
For details on endpoint specific justification please see read-across report in section 13 or find a link in cross-reference “assessment report”.
Reason / purpose for cross-reference:
assessment report
Key result
Parameter:
% degradation (O2 consumption)
Value:
54
Sampling time:
28 d
Remarks on result:
other: Montan wax Type E
Remarks:
in a 10 day window, about 38% had been degraded
Key result
Parameter:
% degradation (CO2 evolution)
Value:
8
Sampling time:
28 d
Remarks on result:
other: Montan wax Type S
Key result
Parameter:
% degradation (O2 consumption)
Value:
22
Sampling time:
28 d
Remarks on result:
other: Montan wax Type OP
Remarks:
in a 10 day window, about 10% had been degraded
Validity criteria fulfilled:
yes
Interpretation of results:
not readily biodegradable
Conclusions:
In reliable studies members of the category of Montan waxes proved to be not readily biodegradable.
Executive summary:

The studies used as source investigated the ready biodegradability of the category of Montan waxes. The study results of the source compound were considered applicable to the target compound and were used for classification and labelling acc. to REGULATION (EC) No 1272/2008. Justification and applicability of the read-across approach (category approach) is outlined in the read-across report in section 13 or find a link in cross reference “assessment report”.

Description of key information

In reliable studies members of the category of montan waxes proved to be not readily biodegradable.

The submission substance is not readily biodegradable.

Note, the key value for CSA was chosen as 'under test conditions no biodegradation observed' based on conservative pre-assumption. However, the key value is not necessary, because no exposure assessment is performed (please refer to chapter 9 and 10 of the CSA).

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed
Type of water:
freshwater

Additional information

Please refer to CSR for further details on study summaries of different members of the Montan waxes category as well as Read-across justification in section 13 'assessment reports'.

Six reliable (four RL 1, two RL 2) OECD 301 studies for different members of the Montan waxes category consistently demonstrate members of the Montan waxes category to be not readily biodegradable.

Six tests on ready biodegradability (according to OECD 301, all performed compliant to GLP) for different members of the Montan waxes category are available: Montan waxes, types S and NaV 101 were tested in the Modified Sturm Test (OECD 301B, CO2-evolution), and Montan waxes types CaV 102, OP, WE4 and E in the Closed Bottle Test (OECD 301D, O2-consumption). Depending on the results, three groups in regard to biodegradability potential may be formed:

Under test conditions no biodegradation observed (below 10%): This was the case for Montan waxes, type S only. The determined mean biodegradation rate after 28 days was 8 %. No inhibitory action towards biodegradation of reference item was observed (RL 1).

Inherent primary biodegradability: According to criteria set by the OECD (OECD/OCDE, 2006) a biodegradation rate above 20% may be interpreted as sign for inherent primary biodegradation. This holds true for Montan waxes, types NaV 101 (RL 1), CaV 102 (RL 1) and OP (RL2). For type NaV 101, a mean biodegradation after 28 days of 21 % was determined and no inhibitory action towards biodegradation of reference item was observed. For type CaV 102, 26.1 % and for type OP, 22% biodegradation was reached within 28 days.

Inherent biodegradability: According to ECHA Guidance on Information Requirements, part R.7B, R.7.9.4, results of ready biodegradability tests almost fulfilling the pass level criterion (60% for ThOD) can be used to prove inherent biodegradability, eliminating the need of further inherent tests. This applies to Montan waxes, type WE 4 (RL 1) and type E (RL 2). For these waxes, biodegradation to 60% and 54%, respectively, within 28 days were determined.

Observed differences in biodegradability might be due to the different tests applied: The least biodegradable Montan waxes, types S (8% biodegradation) and NaV 101 (21% biodegradation) were assessed in the Modified Sturm Test, whereas the other Montan waxes types with biodegradation degrees between 22% and 60% were tested in the Closed Bottle Test.

In conclusion, the members of the Montan waxes category are considered to be not readily biodegradable. However, some biodegradation was observed at least for some of the category members: two from six tested category members are inherently biodegradable and another three may be regarded as inherently primary biodegradable.

Categories Display