Registration Dossier

Environmental fate & pathways

Biodegradation in water: screening tests

Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2010-10-26 - 2010-12-14
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The study was performed in compliance with the Good Laboratory Practice (GLP) regulations (revised in 1997, ENV/MC/CHEM(98)17). The method followed that described in the OECD Guidelines for Testing of Chemicals (Adopted: 4 April 1984) No 301F "Ready Biodegradability: Manometric Respirometry Test".

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report Date:
2010

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
Principles of method if other than guideline:
none
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, adapted
Details on inoculum:
Aerobic activated sludge from domestig waste water treatment plant
Duration of test (contact time):
>= 28 d
Initial test substance concentration
Initial conc.:
ca. 205 mg/L
Based on:
ThOD/L
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
according to guideline
Reference substance
Reference substance:
other: sodium benzoate

Results and discussion

Test performance:
The mean biodegradation after 28 days was 0%.
% Degradation
Parameter:
% degradation (O2 consumption)
Value:
>= 0
Sampling time:
28 d
Details on results:
The test item was not degraded within 28 days.

BOD5 / COD results

Results with reference substance:
The reference item was sufficiently degraded to 75% after 14 days and to 82% after 28 days of incubation.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
under test conditions no biodegradation observed
Conclusions:
The test item was found to be not readily biodegradable under the described test conditions.
Executive summary:

Purpose

The purpose of this assay was to provide information on the biodegradability of the test item in aqueous environment and thus serve as a rational basis for risk assessment for environmental fate in aqueous compartments.

Study Design

The test item was investigated for its ready biodegradability in a Manometric Respirometry Test over a period of 28 days. The biodegradation was followed by the oxygen uptake of the micro organisms during exposure. As a reference item sodium benzoate was tested simultaneously under the same conditions as the test item, and functioned as a procedure control.

Result

Biodegradation of the test item

After correction of the mean biochemical oxygen demand of the inoculum controls at the end of the 28-day exposure period a degradation rate of 0 % was found.

Biodegradation of sodium benzoate

The reference item sodium benzoate was sufficiently degraded to 75 % after 14 days, and to 82 % after 28 days of incubation (ThODNH4).

Biodegradation in the Toxicity Control

In the toxicity control containing both, the test item and the reference item sodium benzoate, 58 % biodegradation was noted within 14 days and 64 % biodegradation was determined after 28 days of incubation. According to the test guidelines the test item can be assumed to be not inhibitory on the activated sludge micro organisms because degradation was > 25 % within 14 days.

Conclusion

The degradation rate of the test item did not reach 60 % within the 10-day window and after 28 days of incubation. The test item is considered not to be readily biodegradable.