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Environmental fate & pathways

Biodegradation in water: screening tests

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Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2008-10-29 to 2009-02-24
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was conducted according to the currently available guideline, according to GLP and the validity criteria are considered as fulfilled.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2009
Report Date:
2009

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge: Domestic waste-water treatment plant, Altenschemel, NW-Lachen-Speyerdorf, Germany
- Preparation of inoculum for exposure: After sampling the sludge was washed twice with tap water.
- Pretreatment: The sludge was mixed with test water and aerated for more then 12 hours until use.
- Initial cell/biomass concentration: 4.5 g dry material per liter
Duration of test (contact time):
28 d
Initial test substance concentrationopen allclose all
Initial conc.:
ca. 29 mg/L
Based on:
test mat.
Initial conc.:
ca. 21 mg/L
Based on:
DOC
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
TEST CONDITIONS
- Composition of medium[g/L]: according to guideline
- Test temperature: 20 - 24°C
- pH: End of the test: 6.7 - 7.3
- Suspended solids concentration: 25.1 mg/L.


TEST SYSTEM
- Culturing apparatus: 2000 mL SCHOTT flasks
- Number of culture flasks/concentration:
2 with inoculum and test substance at ca. 29 mg/L
2 with inoculum only (inoculum control)
2 with inoculum and reference substance Anilin at 24.5 mg/L (procedure control)
1 with inoculum, with test substance at 30.7 mg/L and with reference substance Anilin at 24.5 mg/L (toxicity control)
1 with test substance only and without inoculum.

- Measuring equipment: The formed CO2 was trapped in NaOH. After sampling HCl was added to the traps amd the emitted CO2 was determined by a carbon analyser.
- Test performed in closed vessels: Yes


SAMPLING
- Sampling method: the traps were taken for analysis.
- Sampling frequency: CO2 measurements were performed in dublicate on days 0, 2, 4, 7, 9, 11, 14, 18, 23, 25 and 29

CONTROL AND BLANK SYSTEM
- Inoculum blank: inoculum, but no test substance
- Procedure control: inoculum with reference substance
-Toxicity control: inoculum with test substance and with reference substance


STATISTICAL METHODS:
According to the guideline

Results and discussion

% Degradationopen allclose all
Parameter:
% degradation (CO2 evolution)
Value:
17 - 22
Sampling time:
7 d
Parameter:
% degradation (CO2 evolution)
Value:
30 - 35
Sampling time:
29 d

BOD5 / COD results

Results with reference substance:
The reference item was degraded to a mean of 71 % at day 14 confirming the suitability of the activated sludge.

Any other information on results incl. tables

In the toxicity control the following results were obtained:

Within the first 14 days 45% biodegradation was observed at the test concentration of 30.7 mg/L. Therefore, the test substance can be considered as not toxic to inoculum.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
inherently biodegradable, not fulfilling specific criteria
Conclusions:
According to the guideline all validity criteria were fulfilled. The test substance was not ready biodegradable under the test conditions within 28 days.
Up to a concentration of 30.7 mg/L, the test substance showed no toxic effects to the inoculum.
Executive summary:

Materials and methods

A CO2 evolution test was conducted according to OECD Guideline 301B over a period of 28 days.

Results and discussion

The percentage biodegradation of test substance did not exceed 26 % at the end of the 10 day window. The test item is therefore considered to be not ready biodegradable.

Up to a concentration of 30.7 mg/L, the test substance showed no toxic effects to the inoculum.

According to the guideline all validity criteria were fulfilled.