Registration Dossier

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:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
other: OECD-GUIDELINE No. 301 B) (Paris 1981)
Deviations:
yes
Remarks:
The volume of the test solution was reduced from 3.0 L to 1.5 L.
GLP compliance:
yes
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, adapted
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Sewage treatment plant of CH - 4153 Reinach, Switzerland
- Pretreatment: According to guideline
Duration of test (contact time):
28 d
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
TEST CONDITIONS
- Composition of medium: According to guideline
- Solubilising agent (type and concentration if used): The test substance was added to the medium, homogenized with Nonylphenol 10E05P0
- Test temperature: 22± 2 °C
- pH adjusted: No
- Aeration of dilution water: Yes, 24 hours in the test vessel

TEST SYSTEM
- Culturing apparatus: 2 Liter flasks equipped with gas inlet and magnetic stirrer
- Number of culture flasks/concentration:
- Method used to create aerobic conditions: Air flow, appr. 25 mL/min free of carbon dioxide
- Method used to create anaerobic conditions:
- Details of trap for CO2 and volatile organics if used: Absorbers filled with 200 mL 0.05 N sodium hydroxide

SAMPLING
- Sampling frequency: At day 4, 7, 11, 15, 18, 22, 27, and 28
- Sampling method: Determination of the initial CO2 of the 0.05 N sodium hydroxide and the CO2 absorbed in the absorbers

CONTROL AND BLANK SYSTEM
- Inoculum blank: Yes
- Other: Vehicle control
Reference substance:
aniline
Remarks:
20 mg/L
Parameter:
% degradation (CO2 evolution)
Value:
0
Sampling time:
28 d
Remarks on result:
other: 10 mg test substance/L
Parameter:
% degradation (CO2 evolution)
Value:
3
Sampling time:
28 d
Remarks on result:
other: 20 mg test substance/L
Results with reference substance:
Biodegradation 87.2 % in 28 days

Table 1. CO2 evolution in the controls and in the reference substance cultures

Day
CO2 evol. CO2 evol. Biodegrad.
Blank Blank + Vehicle Aniline (20 mg/L)
(mg) (mg)* (mg) (mg)* (mg) (mg)* (%) (%)*
4 6 6 7 7 38.5 38.5 45.3 45.3
7 3 9.1 4 11 20.7 59.2 24.3 69.6
11 3.9 12.9 3.6 14.6 7.4 66.6 8.7 78.3
15 3.8 16.8 4.4 18.9 2.4 69 2.8 81.1
18 2.8 19.6 3.1 22 4.4 73.4 5.2 86.3
22 3.3 22.9 3.9 25.9 -1.2 72.2 -1.4 84.9
27 6.9 29.8 5.9 31.9 -0.5 71.7 -0.6 84.3
28 -0.8 29 -0.1 31.7 2.5 74.2 2.9 87.2

* cumulative values

For calculation of the degradation, the Blank+Vehicle is used. The Blank shows the behavior of the inoculum.

Table 2. CO2 evolution in TK 11319 cultures

Day Concentration 10 mg/L Concentration 20 mg/L
CO2 evol. Biodegrad. CO2 evol. Biodegrad.

(mg) (mg)* (%) (%)* (mg) (mg)* (%) (%)*
4 0.2 0.2 0.4 0 2.5 2.5 3 3
7 -1 -0.8 -2.4 -2 -1.2 1.2 -1.5 2
11 -0.1 -1 -0.4 -2 0.4 1.7 0.5 2
15 -0.6 -1.6 -1.5 -4 -0.4 1.3 -0.5 2
18 0.5 -1.1 1.2 -3 0.6 1.9 0.7 2
22 -1.6 -2.6 -3.8 -6 -1.3 0.6 -1.5 1
27 -0.1 -2.8 -0.4 -7 0.7 1.2 0.8 2
28 1.8 -1 4.4 -2 1.4 2.6 1.7 3

* cumulative values

The negative degradation values are within the variation of the method.

Validity criteria fulfilled:
yes
Interpretation of results:
under test conditions no biodegradation observed
Conclusions:
After 28 days, the substance achieved 3% biodegradation - thus EC 404-363-3 is not readily biodegradable according to OECD criteria.
Executive summary:

In this guideline (OECD 301 B) study conducted with GLP certification, the test material (EC 404-363-3) was determined to not be readily biodegradable. The test was conducted in aerobic conditions, using an adapted sludge sourced from a municipal sewerage treatment plant. 3% test material biodegradation was observed 28 days (CO2 evolution).

Description of key information

Study carried out according to guideline and with GLP compliance.

Key value for chemical safety assessment

Additional information

A test on ready biodegradability was conducted according to GLP and OECD 301B (CIBA-GEIGY Ltd. 1989). After 28 d only 3% biodegradation was observed. Therefore, the test substance is poorly biodegradable and not readily biodegradable (according to OECD criteria).

The test substance is not readily biodegradable (according OECD criteria). Poorly biodegradable.