Registration Dossier

Diss Factsheets

Environmental fate & pathways

Biodegradation in water: screening tests

Currently viewing:

Administrative data

Link to relevant study record(s)

biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study performed according to guideline, but no data on substance available and no GLP
according to guideline
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
GLP compliance:
Oxygen conditions:
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): supernatant of homogeneized activated sludge, from the domestic waste water treatment plant of Taunusstein-Bleidenstadt (Germany)
Duration of test (contact time):
28 d
Initial conc.:
10 mg/L
Based on:
other: TOC
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
- Sampling frequency: day 2, 4, 7, 13, 20, 28 and 30

- Volume: 3500 mL

- Inoculum blank: yes
- Toxicity control: yes
Reference substance:
benzoic acid, sodium salt
~ 20 mg/L TOC
Key result
% degradation (CO2 evolution)
Sampling time:
28 d
Remarks on result:
other: average of the 2 tests
Details on results:
Test 1:6% within 28 days
Test 2: 0% within 28 days
The test substance did not show toxicity to the inoculum.
Results with reference substance:
20 mg/L = 90% biodegradation, > 60% biodegradation where observed after 5 days

Sampling day Concentration: 126 mg/3.5 L (ThCO2: 128.7 mg CO2/3.5 L)
mg CO2 (cumulative) % TCO2 (= % degradation)
2 0.76 1
5 1.27 1
7 1.93 1
13 3.64 3
20 5.31 4
28 7.52 6
30 10.99 9

Sampling day Concentration: 127 mg/3.5 L (ThCO2: 129.7 mg CO2/3.5 L)
mg CO2 (cumulative) % TCO2 (= % degradation)
2 0.25 < 1
5 0.60 y 1
7 0.68 1
13 0.80 1
20 -0.42 /
28 -1.17 /
30 0.03 < 1

Total CO2 evolution of the blank test: 65.3 mg CO2 / 3500 mL within 28 days

Validity criteria fulfilled:
not specified
Interpretation of results:
under test conditions no biodegradation observed
The test substance is not readily biodegradable.

Description of key information

 Not readily biodegradable (by OECD criteria).

Key value for chemical safety assessment

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

Additional information

The substance has been tested according OECD 301B with a concentration of the test item exceeding the solubility limit by the factor 16. Practically no indication of biodegradation was observed.


Furthermore, several studies conducted with melamine and cyanuric acid themselves are available.


For the component 108 -78 -1(Melamine):

Test results of a MITI test for ready biodegradability, 3 Zahn-Wellens assays for inherent biodegradability and 2 studies on Biochemical Oxygen Demand are reported. The individual results of the studies are consistent: Melamine is not readily biodegradable and also not inherently biodegradable.

With activated sludge taken from an industrial waste water treatment plant as the inoculum, a degradation of DOC of up to 16 % was observed within 20 d (Pagga 1991). A rapid and complete primary degradation of the molecule within 8 h was detected with an activated sludge taken from an industrial waste water treatment plant from a producer of melamine (Fimberger 1997). Addition of glucose, in the absence of NH4+, enables the microorganisms to use melamine as the only nitrogen source (Fimberger 1997). Degradation occurs by hydrolytic deamination to ammeline, ammelide and cyanuric acid, and lastly to CO2 and NH4+ (Fimberger 1997).


For the component 108 -80 -5 (Cyanuric acid):

The component is neither readily not inherently biodegradable.