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:
April 7, 2003 to August 18, 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 F (Ready Biodegradability: Manometric Respirometry Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Specific details on test material used for the study:
TEST MATERIAL
Name ( stated on the report) : TETRAHYDRO CITRAL
Appearance: Colourless to pale yellow liquid
Batch: 9000492013
Expiry date: May 12, 2003.

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
Fresh activated sludge from a biological waste water treatment plant treating predominantly domestic sewage (City of Geneva, Peney-Dessous) was used.
The sludge is collected in the morning, washed three times in the mineral medium (by centrifuging at 1000 g for 10 minutes, discarding the supernatant and resuspending in mineral medium) and kept aerobic until being used on the same day.

Duration of test (contact time):
35 d
Initial test substance concentration
Initial conc.:
100 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Reference substance
Reference substance:
other: Sodium benzoate (Fluka, Buchs, Switzerland, Art. No. 71300), purity : min. 99.0 %.

Results and discussion

% Degradation
Key result
Parameter:
% degradation (O2 consumption)
Value:
64
Sampling time:
28 d
Details on results:
Biodegradation starts on day 3 and reaches 51% at the end of the 10-day window (days 3 to 13).

BOD5 / COD results

Results with reference substance:
The curves obtained with the reference substance alone and with TETRAHYDRO CITRAL + reference substance show no toxic effect of TETRAHYDRO CITRAL to the micro-organisms at the test concentration (100 mg/l).

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable, but failing 10-day window
Conclusions:
TETRAHYDRO CITRAL undergoes 64% biodegradation after 28 days (67% after 35 days) in the test conditions. Biodegradation starts on day 3 and reaches 51% at the end of the 10-day window (days 3 to 13).
The curves obtained with the reference substance alone and with TETRAHYDRO CITRAL + reference substance show no toxic effect of TETRAHYDRO CITRAL to the micro-organisms at the test concentration (100 mg/l).

Executive summary:

The Ready Biodegradability of TETRAHYDRO CITRAL was determined by the Manometric Respirometry Test according to the OECD Guidelines for Testing of Chemicals, Method No. 301 F.

TETRAHYDRO CITRAL undergoes 64% biodegradation after 28 days (67% after 35 days) in the test conditions.

Biodegradation starts on day 3 and reaches 51% at the end of the 10-day window (days 3 to 13).

The curves obtained with the reference substance alone and with TETRAHYDRO CITRAL + reference substance show no toxic effect of TETRAHYDRO CITRAL to the micro-organisms at the test concentration (100 mg/l).