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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:
June 8-July 10, 2012
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2012
Report date:
2015

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
(Z)-non-6-enal
EC Number:
218-900-9
EC Name:
(Z)-non-6-enal
Cas Number:
2277-19-2
Molecular formula:
C9H16O
IUPAC Name:
6-Nonenal, (6Z)-
Test material form:
liquid

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge (adaptation not specified)
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Bois-de-Bay, Satinay, Switzerland, collected in the morning and used the same day
- Laboratory culture:
- Method of cultivation:
- Storage conditions:
- Storage length: used the same day as collected
- Preparation of inoculum for exposure: washed three times with mineral medium, centrifuged at 1000 g for 10 minutes, then resuspended
- Pretreatment:
- Concentration of sludge: 5.00 mL in 225 mL medium,, 2.00 mL in 103 mL medium
- Initial cell/biomass concentration: 30 mg/L
Duration of test (contact time):
32 d
Initial test substance concentration
Initial conc.:
30 mg/L
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
TEST CONDITIONS
- Composition of medium: 8.5 g KH2PO4, 21.75 g K2HPO4, 33.4 g Na2HPO4*H2O, and 0.5 g NH4Cl dissolved in water and brought to 1 L. 50 mL of this solution was mixed with 2 L of water. Then 5 mL of a solution made with 27.5 g CaCl2 in 1 L of water. Then 5 mL of a solution containing 22.5 g of MgSO4 * 7H2O made up to 1 L was added. Then 5 mL of a solution made with 0.25 g FeCl3 * 6H2O and one drop of concentrated HCl made up to 1 L was added. The mineral medium was then made up to 5 L with deionized water.
- Additional substrate: No
- Solubilising agent (type and concentration if used): None
- Test temperature: 22.1-22.5 degrees C
- pH: 7.4
- pH adjusted: yes
- CEC (meq/100 g):
- Aeration of dilution water: No
- Suspended solids concentration: 1.53 g/L dry material
- Continuous darkness: yes/no
- Other:

TEST SYSTEM
- Culturing apparatus: Oxitop bottles
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions:
- Method used to create anaerobic conditions:
- Measuring equipment: Oxitop respirometers
- Test performed in closed vessels due to significant volatility of test substance: Yes
- Test performed in open system:
- Details of trap for CO2 and volatile organics if used: Oxitop system used. Sodium hydroxide pellets were used to absorb carbon dioxide.
- Other:

SAMPLING
- Sampling frequency: Measurements were taken daily.
- Sampling method: Pressure in the flasks is measured by equipment in the bottle tops.
- Sterility check if applicable:
- Sample storage before analysis:
- Other:

CONTROL AND BLANK SYSTEM
- Inoculum blank: Yes
- Abiotic sterile control: No
- Toxicity control: No
- Other:

STATISTICAL METHODS:
Reference substance
Reference substance:
benzoic acid, sodium salt

Results and discussion

Test performance:
The biodegradation of the sodium benzoate was greater than 40% after 7 days, and greater than 65% after 14 days. The results for the test substance were within 20% of each other. The test results are therefore valid.
% Degradation
Key result
Parameter:
% degradation (O2 consumption)
Value:
83
Sampling time:
28 d
Details on results:
The test substance was 83% degraded by day 28, and 84% degraded by 32 days.

BOD5 / COD results

Results with reference substance:
106% in 28 days

Any other information on results incl. tables

One of the reference substance flasks malfunctioned. Since only one flask is needed for the reference substance results, this did not affect the validity of the results.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
The substance cis-nonen-6-al is readily biodegradable.
Executive summary:

The biodegradability of the test substance was determined in an OECD 301F study. 30 mg/L of test substance was added to flasks with mineral medium and activated sludge. The oxygen consumption was then recorded daily for 32 days. The substance was 83% biodegraded in 28 days, and the 10 -day window was met. Results with the positive control substance, sodium benzoate, were also valid. The test substance is therefore readily biodegradable.