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Environmental fate & pathways

Biodegradation in water: screening tests

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Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From 1st April 2014 to 3rd July 2014
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: According to the OECD Guideline 301B and it is GLP.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2014
Report date:
2014

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
5-methyl-2-(1-methylbutyl)-5-propyl-1,3-dioxane
EC Number:
279-482-1
EC Name:
5-methyl-2-(1-methylbutyl)-5-propyl-1,3-dioxane
Cas Number:
80480-24-6
Molecular formula:
C13H26O2
IUPAC Name:
5-methyl-2-(1-methylbutyl)-5-propyl-1,3-dioxane
Details on test material:
- Name of test material (as cited in study report): Troenan
- Physical state: Colourless liquid
- Stability under test conditions: This is the subject of this study.
- Storage condition of test material: At 2-8°C (4°C), protected from light

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
other: Activated sludge from the sewage plant of Taunusstein-Bleidenstadt dealing with predomi¬nantly domestic sewage
Details on inoculum:
Prior to use a sample of activated sludge from the sewage plant at Taunusstein-Bleidenstadt was washed twice with mineral nutrient solution of the CO2-Evolution-Test to eliminate organic components and carbonates from the sludge. After resolution with mineral nutrient medium the sludge was aerated by means of compressed humidified air for about four hours. Before use as inoculum for the CO2-Evolution-Test the sludge was homogenised in a "Waring Blender" at low speed for 2 minutes and then filtered through a cotton filter previously carefully rinsed with deionised water. The filtrate was used as inoculum (1% of the final volume of the test solution) on the same day of preparation.
Duration of test (contact time):
28 d
Details on study design:
Test item (1st Test solution, Test Item):
Concentration: 50.68 mg/3.5 L / 10 mg TOC1)/L
ThCO2):2673.5 mg CO2/g test item
Theoretical amount of CO2 being generated if the test item is completely transformed to CO2: 135.5 mg CO2/ 3500 mL test solution
Inoculum: Activated sludge from the sewage plant of Taunusstein-Bleidenstadt dealing with predominantly domestic sewage
Volume of the test solution: 3500 mL
Functional control: Sodiumbenzoate, 120.3 mg/3.5 L test solution; equivalent to 256.39 mg CO2, 86% biodegradation within 28 d (+ 1d of purging off the CO2 from the test solution)
Total CO2 Evolution of the Blank: 125.8 mg CO2 / 3.5 L within 28 d (+ 1d of purging off the CO2 from the test solution)

Test item (2nd Test Solution, Test Item):
Concentration: 48.03 mg/3.5 L / 10 mg TOC1)/L
ThCO2): 2673.5 mg CO2/g test item
Theoretical amount of CO2 being generated if the test item is completely trans¬formed to CO2: 128.4 mg CO2/ 3500 mL test solution
Inoculum: Activated sludge from the sewage plant of Taunusstein-Bleidenstadt dealing with predominantly domestic sewage
Volume of the test solution: 3500 mL
Functional control: Sodiumbenzoate, 120.3 mg/3.5 L test solution; equivalent to 256.39 mg CO2, 86% biodegradation within 28 d (+ 1d of purging off the CO2 from the test solution)
Total CO2 Evolution of the Blank: 125.8 mg CO2 / 3.5 L within 28 d (+ 1d of purging off the CO2 from the test solution)

Test item (3rd Test Solution, Sodium Benzoate):
Control Item: Sodiumbenzoate
Concentration: 120.3 mg/3.5 L / 20 mg TOC1)/L
ThCO2): 2131.2 mg CO2 / g control item
Theoretical amount of CO2 being generated if control item is completely trans¬formed to CO2: 256.39 mg CO2/ 3500 mL test solution
Inoculum:Activated sludge from the sewage plant of Taunusstein-Bleidenstadt dealing with predominantly domestic sewage
Volume of the test solution: 3500 mL
Total CO2 Evolution of the Blank: 125.8 mg CO2 / 3.5 L within 28 d (+ 1d of purging off the CO2 from the test solution)

Test item (4th Test Solution, Toxicity Control):
Item: TROENAN + Sodiumbenzoate (Tox-Control)
Concentration of the test item: 49.72 mg / 3.5 L / 10 mg TOC1)/L
Concentration of sodiumbenzoate: 122.0 mg / 3.5 L / ≈20 mg TOC1)/L
Theoretical amount of CO2 being generated if all the carbon material in the test solution is transformed to CO2: 392.92 mg CO2/ 3500 mL test solution
Inoculum: Activated sludge from the sewage plant of Taunusstein-Bleidenstadt dealing with predominantly domestic sewage
Volume of the test solution: 3500 mL
Sodiumbenzoate (separatetest solution): 120.3 mg/3.5 L test solution; equivalent to 256.39 mg CO2, 85 % biodegradation within 28 d (+ 1d of purging off the CO2 from the test solution)
Test item (separate test solutions): 50.68 mg/3.5 L test solution; equivalent to 135.5 mg CO2, 18% biodegradation within 28 d (+ 1d of purging off the CO2 from the test solution). 48.03 mg/3.5 L test solution; equivalent to 128.4 mg CO2, 15% biodegradation within 28 d (+ 1d of purging off the CO2 from the test solution)
Total CO2 Evolution of the Blank:125.8 mg CO2 / 3.5 L within 28 d (+ 1d of purging off the CO2 from the test solution)


Results and discussion

% Degradation
Parameter:
% degradation (TOC removal)
Value:
17
Sampling time:
28 d
Remarks on result:
other: mean value
Details on results:
Calculated from the organic carbon content of the test item and the measured CO2 generation, 18% of the theoretical CO2 (ThCO2) has been generated by the test item within 28d of test period in the first culture with 50.68 mg of test item. 15% of the theoretical CO2 (ThCO2) has been generated by the test item within 28d in the second culture with 48.03 mg of test item. The calculated mean degradation value of the test item was 17%.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
other: not readily biodegradable
Conclusions:
The threshold of 60% for “ready biodegradability” requirement was not met within both test treatments. Thus, the test item may be regarded as “not readily biodegradable". The control item sodium benzoate was degraded 86%, the "10-days-window" being met within 7 days (74%).
Executive summary:

The substance was tested for ready biodegradability according to 'CO2-Evolution-Test' (OECD Guideline 301B). Calculated from the organic carbon content of the test item and the measured CO2 generation, 18% of the theoretical CO2 (ThCO2) has been generated by the test item within 28d of test period in the first culture with 50.68 mg of test item. 15% of the theoretical CO2 (ThCO2) has been generated by the test item within 28d in the second culture with 48.03 mg of test item. The calculated mean degradation value of the test item was 17%. The threshold of 60% for “ready biodegradability” requirement was not met within both test treatments. Thus, the test item may be regarded as “not readily biodegra¬dable". The control item sodium benzoate was degraded 86%, the "10-days-window" being met within 7 days (74%). The total CO2-evolution of the Blank was 125.8 mg CO2 / 3.5 litres of test solution. Thus the test is regarded to be valid. The results obtained with the toxicity control indicate that there was no toxicity of the test item towards microorganisms at the concentration used within the test.