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
Study period:
19.05.2003 - 17.06.2003
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2003
Report Date:
2003

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 301 A (Ready Biodegradability: DOC Die Away Test)
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Details on test material:
- Name of test material (as cited in study report): 2,3,5-Trimethylhydrochinone
- Lot/batch No.: T5600/4703/04/25
- Analytical purity: >= 99.5 %;
water solubility: not indicated.

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Details on inoculum:
Concentration of sludge: 30 mg/I (dry substance)
Duration of test (contact time):
28 d
Initial test substance concentrationopen allclose all
Initial conc.:
20 mg/L
Based on:
DOC
Initial conc.:
29 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
DOC removal
Reference substance
Reference substance:
aniline

Results and discussion

% Degradation
Key result
Parameter:
% degradation (DOC removal)
Value:
ca. 65
Sampling time:
28 d
Details on results:
Kinetic of test substance (in %):
ca. 18 after 3 day(s)
ca. 32 after 7 day(s)
ca. 41 after 14 day(s)
ca. 52 after 21 day(s)
ca. 65 after 28 day(s)

BOD5 / COD results

Results with reference substance:
Kinetic of control substance (in %):
= 10 after 3 day(s)
= 96 after 5 day(s)
Degradation products: not measured

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
The reference sample biodegraded within 5 days to a degree of 96%. The difference of extremes of replicate values of the removal of the test chemical at the end of the test is less than 20%.
Interpretation of results:
not readily biodegradable
Conclusions:
Trimethylhydroquinone is not rapidly biodegradable as determined in a DOC Die-away test.
Executive summary:

As a criterion for the classification as rapidly biodegradable a DOC-elimination of 70% of the test item within a 10 day-window during a total test duration of 28 days is considered. The test samples of trimethylhydroquinone do not meet this criterion since only 65% DOC-elimination during the total test duration were attained. Hence, trimethylhydroquinone is classified as not rapidly biodegradable.