Registration Dossier

Environmental fate & pathways

Biodegradation in water: screening tests

Administrative data

biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
1 (reliable without restriction)

Data source

Reference Type:
study report
Report Date:

Materials and methods

Test guideline
according to
OECD Guideline 310 (Ready Biodegradability - CO2 in Sealed Vessels (Headspace Test)
Principles of method if other than guideline:
ISO 14593, Evaluation of ultimate aerobic biodegradability
of organic compounds in aqueous medium method by analysis
ofinorganic carbon in sealed vessels (CO2 headspace test)
adopted March 1999

Guideline OECD 310 (CO2 in sealed vessels (Headspace Test). US Environmental Protection Agency (EPA), Office of Prevention, Pesticides and Toxic Substances, (OPPTS) Method 835.3120, Sealed-Vessel Carbon Dioxide Production test, adopted January 1998.
GLP compliance:

Test material


Study design

Oxygen conditions:
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
treatment works, which treats predominantly domestic waste three days before the start of the test. On the day of collection, the sample was passed through a sieve with a mesh of ca. 1 mm2. A sub-sample (ca. 300 ml) was removed and centrifuged at ca. 3000 rpm for ca. 1 minute and the supernatant removed. The sample was then made up to volume with mineral salts medium (MSM, Appendix 1) and centrifuged. This procedure was carried out twice more and the sample was maintained aerated until required. Aliquots (10 ml) of a homogenised sample of the washed activated sludge were filtered through dried (approximately 105°C) and pre-weighed Whatman GF/C filter papers. The filters were dried for at least one hour, allowed to cool and re-weighed. The solids level in the sludge was determined and then an appropriate volume used to inoculate control and test vessels to give a final suspended solids concentration of 4 mg/l.
Reference substance
Reference substance:
other: Sodium Benzoate

Results and discussion

% Degradation
% degradation (CO2 evolution)
>= 0 - <= 2.6
Sampling time:
28 d
Remarks on result:
other: Std. deviation not determined
Details on results:
Points of degradation plot (test substance):
1.2 % degradation after 5 d
.3 % degradation after 7 d
2.6 % degradation after 14 d
0 % degradation after 22 d
.1 % degradation after 28 d

BOD5 / COD results

Results with reference substance:
Points of degradation plot (reference substance):
62.9 % degradation after 5 d
65.9 % degradation after 7 d
80.1 % degradation after 14 d
85.8 % degradation after 22 d
90.5 % degradation after 28 d

Applicant's summary and conclusion

Interpretation of results:
other: not readily biodegradable