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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:
2009/03/16-2009/04/17
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: No amendment to the study plan was requested. No incident, which could have affected the quality or the interpretation of the results obtained, was observed.

Data source

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

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Remarks:
2008/30/04

Test material

Constituent 1
Reference substance name:
LCE08129:Acetalization products between glucose and C14 alcohol.
IUPAC Name:
LCE08129:Acetalization products between glucose and C14 alcohol.
Details on test material:
- Identity: LCE08129
- Batch No.: Lot T82925
- Expiration Date: 15-Jul-2010 (retest date)
- Solubility in Water: Emulsifiable
- Aggregate State / Physical Form at
- Room Temperature: Solid
- Storage Conditions: At room temperature at about 20 °C, away from direct sunlight.

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Details on inoculum:
The study was performed with aerobic activated sludge from a wastewater treatment plant (ARA Ergolz II, Füllinsdorf, Switzerland) treating predominantly domestic wastewater.
Duration of test (contact time):
ca. 28 d
Initial test substance concentration
Initial conc.:
ca. 50 mg/L
Based on:
act. ingr.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
The test item was added to the designated test flasks with test water. No emulsifiers or solvents were used.
The sludge was washed twice with tap water by centrifugation and the supernatant liquid phase was decanted. A homogenized aliquot of the final sludge suspension was weighed, thereafter dried and the ratio of wet to dry weight was calculated.
Based on this ratio, calculated amounts of wet sludge were suspended in test water to obtain a concentration equivalent to 4 g (±10%) dry material per liter.
During the holding period of three days prior to use, the sludge was aerated at room temperature.
Prior to use, the sludge was first thoroughly mixed and then diluted with test water to a concentration of 1 g per liter (dry weight basis). Based on the determined dry weight of this diluted activated sludge, defined amounts were added to test water to obtain a final concentration of 30 mg dry material per liter.
Reference substance
Reference substance:
benzoic acid, sodium salt

Results and discussion

Test performance:
The percent biodegradation of the test item was calculated based on the theoretical oxygen demand (ThOD) of 2.91 mg O2/mg test item.
The biochemical oxygen demand (BOD) of LCE08129 in the test media significantly increased from test start until test termination after 28 days. At the end of the test the mean biodegradation of LCE08129 amounted to 91%.
% Degradation
Parameter:
% degradation (O2 consumption)
Value:
ca. 91
Sampling time:
28 d

BOD5 / COD results

Results with reference substance:
In the procedure controls, the reference item was degraded by an average of 88% by Day 14, thus confirming suitability of the activated sludge. At the end of the test (Day 28), the reference item was degraded by an average of 94%.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
Consequently, LCE08129 was found to be highly biodegradable under the test conditions within 28 days. The pass level for ready biodegradability, i.e. biodegradation of at least 60% of the ThOD in a 10-day window within the 28-day period of the test, was reached.
Executive summary:

The test item LCE08129 was investigated for its ready biodegradability in a manometric respirometry test over 28 days according to the EU Commission Directive 92/69 EEC, C.4-D Commission Regulation (EC) No 440/2008, C.4-D and the OECD Guideline for Testing of Chemicals No. 301 F.

The percent biodegradation of the test item was calculated based on the theoretical oxygen

demand (ThOD) of 2.91 mg O2/mg test item.

The biochemical oxygen demand (BOD) of LCE08129 in the test media significantly increased from test start until test termination after 28 days. At the end of the test the mean biodegradation of LCE08129 amounted to 91%.

Consequently, LCE08129 was found to be highly biodegradable under the test conditions within 28 days. The pass level for ready biodegradability, i.e. biodegradation of at least 60% of the ThOD in a 10-day window within the 28-day period of the test, was reached.

In the toxicity control, containing both LCE08129 and the reference item sodium benzoate, LCE08129 had no inhibitory effect on the activity of activated sludge microorganisms at the tested concentration of 50 mg/L.

In the procedure controls, the reference item sodium benzoate was degraded by an average of 88% by Day 14, and reached an average biodegradation of 94% by the end of the test (Day 28), thus confirming suitability of the activated sludge.