Registration Dossier

Environmental fate & pathways

Biodegradation in water: screening tests

Currently viewing:

Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1992
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study and GLP

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1992
Report date:
1992

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
EU Method C.4-A (Determination of the "Ready" Biodegradability - Dissolved Organic Carbon (DOC) Die-Away Test)
Deviations:
no
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 301 A (Ready Biodegradability: DOC Die Away Test)
GLP compliance:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
Ethyl cyanoacetate
EC Number:
203-309-0
EC Name:
Ethyl cyanoacetate
Cas Number:
105-56-6
Molecular formula:
C5H7NO2
IUPAC Name:
ethyl 2-cyanoacetate
Constituent 2
Reference substance name:
[SPEC][/SPEC][SYN][/SYN]
IUPAC Name:
[SPEC][/SPEC][SYN][/SYN]
Constituent 3
Reference substance name:
[CS]000000157834[/CS]
IUPAC Name:
[CS]000000157834[/CS]
Details on test material:
Batch no. Tank 434
ID no. 3633/81410

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, adapted
Details on inoculum:
- Date of sampling: 10.07.1992 from an domestic sewage plant
- The activated sludge was centrifuged for 10 min, the supernatant was discarded and the sludge was resuspended in a nutrient solution. The sludge was centrifuged and resuspended again. The inoculum was kept aerobic until use.
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
10.84 mg/L
Based on:
DOC
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
inorg. C analysis
Details on study design:
TEST CONDITIONS

- 2 test vessels with test substance (10.84 mg DOC/l) and inoculum

- Composition of nutrient solution:
8.5 g KH2PO4
21.75 g K2HPO4
33.3 g Na2HPO4 x 2 H2O
20.0 g NH4Cl
22.5 g MgSO4 x 7 H2O
27.5 g CaCl2
0.25 g FeCl3 x 6 H2O


- Test temperature: 22 ± 1°C
- Continuous darkness: yes
- The test vessels were 2000 ml Erlenmeyer flasks loosely closed with aluminum foil

- Sampling frequency: on day 0, 7, 14, 21, 27 and 28
- Sampling method: repeat determination, one acidulated and one outgased sample ( removal of the anorganic carbon)


CONTROL AND BLANK SYSTEM
- Inoculum blank: 2 test vessels without any test substance, but with the inoculum
- Control system: 2 test vessels with reference substance (benzoic acid, sodium salt) 9.44 mg DOC/l and inoculum

Reference substance
Reference substance:
benzoic acid, sodium salt

Results and discussion

% Degradation
Parameter:
% degradation (DOC removal)
Value:
98
Sampling time:
28 d

BOD5 / COD results

Results with reference substance:
The reference substance benzoic acid, sodium salt achieved within 10 days after a first excess of the 10%-degradation threshold a degradation of 101%. This suggest that the inoculum has an sufficient activity.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
The test substance Ethyl cyanoacetate achieved in the DOC-DIE AWAY Test within 28 days a DOC degradation of 98 %. Within 10 days after a first excess of the 10 %-degradation threshold the degradation rate is > 70 %. Therefore the test substance Ethyl cyanoacetate can be describe as readily biodegradable.
Executive summary:

The test substance Ethyl cyanoacetate achieved in the DOC-DIE AWAY Test within 28 days a DOC degradation of 98 %. Within 10 days after a first excess of the 10 %-degradation threshold the degradation rate is > 70 %. Therefore the test substance Ethyl cyanoacetate can be describe as readily biodegradable.