Registration Dossier

Environmental fate & pathways

Biodegradation in water: screening tests

Administrative data

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:
other: Guideline study under GLP conditions

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1997
Report Date:
2001

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 310 (Ready Biodegradability - CO2 in Sealed Vessels (Headspace Test)
Principles of method if other than guideline:
CO2-Headspace Test following ISO/CD 14593 (draft, 1996); the evolved CO2 is analysed as TIC (total inorganic carbon) in the liquid phase. The biodegradation is calculated by comparing the increase in TIC levels with the amount of test substance  (TOC) added initially.
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Methyl formate
- Analytical purity: 97.3%

Study design

Oxygen conditions:
aerobic
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): activated sludge from a laboratory waste water treatment plant
- Concentration of sludge: 4.0 mg/L dw
Duration of test (contact time):
28 d
Initial test substance concentrationopen allclose all
Initial conc.:
20 mg/L
Based on:
DOC
Initial conc.:
51.7 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
TEST SYSTEM
- Culturing apparatus: 160 mL flasksm liquid volume: 100 mL, headspac: 60 mL
- Number of culture flasks/concentration: 3
- Test performed in closed vessels due to significant volatility of test substance: yes


SAMPLING
- Sampling frequency: weekly


CONTROL AND BLANK SYSTEM
- Inoculum blank: 3 replicates
- Abiotic sterile control: 3 replicates
- Toxicity control: 3 replicates
Reference substance
Reference substance:
aniline

Results and discussion

% Degradation
Parameter:
% degradation (CO2 evolution)
Value:
93
Sampling time:
28 d
Details on results:
Additional biodegradation values (day 28):

Inhibition control (IC): 90 % TIC/TOC
Abiotic elimination control: -2 % TIC/TOC

Kinetic of test substance (in %):
77 after 7 day(s)
91 after 14 day(s)
93 after 21 day(s)
93 after 28 day(s)

BOD5 / COD results

Results with reference substance:
Kinetic of control substance (in %):
72 after 14 day(s)
91 after 28 day(s)

Any other information on results incl. tables

In the initial report the test item was classified as "biodegradable",although the test results fulfilled all OECD criteria for ready  biodegradability, . 
This was because at the time the study was conducted and the report was  written, the applied test method was still a draft procedure. 

Since in  the meantime it has become an international standard, the result of the  test can now be stated as "Readily Biodegradable" 

(based on the data presented for both the CO2 evolution and the removal of DOC).

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable