Diethyl sulphate, compound with 2-(heptadec-8-enyl)-4,5-dihydro-1H-imidazole-1-ethanol (1:1)

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017-12-19 to 2018-01-16

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Version / remarks:

1992-07-17

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: R-127 / Batch 170825
- Expiration date of the lot/batch: 2019-06-19

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Dark, dry place at room temperature
- Solubility and stability of the test substance in the solvent/vehicle: soluble in water

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Municipal sewage treatment plant, 31137 Hildesheim, Germany
- Storage length: 7 d
- Preparation of inoculum for exposure: The activated sludge was washed twice with chlorine free tap water. After the second washing the settled sludge was resuspended in min-eral salts medium and was maintained in an aerobic condition by aera-tion for 2 hours. Thereafter the sludge was homogenized with a blender. After sedimentation the supernatant was decanted and main-tained in an aerobic condition by aeration with CO2-free air for 7 days. 15 mL/L were used to initiate inoculation.
- Pretreatment: see above
- Initial cell/biomass concentration: Approx. 107 - 108 CFU/L
- Water filtered: no

Duration of test (contact time):

28 d

Initial conc.:

22 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Test temperature: Nominal: 20 - 24, ± 1 °C; Actual: 20.8 – 21.1 °C
- pH: 7.77 at start, 7.76 at completion
- pH adjusted: no
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: brown glass bottels
- Number of culture flasks/concentration: 2 for inoculum control, 1 for functional control, 2 for test item, 1 for toxicity control
- Method used to create aerobic conditions: aeration
- Measuring equipment:
OxiTop OC110 controller with software Achat OC, WTW
OxiTop measuring heads, WTW
Stirring platform, WTW
Climatic exposure test cabinet, RUMED RUBARTH APPARATE GMBH pH-Meter, Multi 350i, WTW
Datalogger 174 T, TESTO
Analytical balance, SARTORIUS
Balance, KERN

- Test performed in closed vessels due to significant volatility of test substance:
- Test performed in open system:
- Details of trap for CO2 and volatile organics if used:
- Other:

SAMPLING
- Sampling frequency:
- Sampling method:
- Sterility check if applicable:
- Sample storage before analysis:
- Other:

CONTROL AND BLANK SYSTEM
- Inoculum blank:
- Abiotic sterile control:
- Toxicity control:
- Other:

STATISTICAL METHODS:

Reference substance:

benzoic acid, sodium salt

Test performance:

The temperature in the incubator was documented continuously throughout the test.

At test start the pH-values of the prepared solutions in the measuring flasks (inoculum control and functional control) and the prepared so-lutions in the separate replicates (test item and toxicity control), were determined. At test end the pH-values of the test solutions in the brown glass bottles were determined.

Key result

Parameter:

% degradation (O2 consumption)

Value:

1

Sampling time:

28 d

Details on results:

Theoretical Oxygen Demand
The biodegradation in % was calculated based on the ThOD of 2.34 mg O2/mg test item.

Colony Forming Units of the Inoculum
Colony forming units (CFU) of the inoculum were determined prior to test start by standard dilution plate count: 1.52  109 CFU/L. The CFU concentration of the inoculum corresponds to approx.
1.52 x 107 CFU/L in the final test solution.

Results of the Functional Control
The pass level for ready biodegradation (≥ 60% degradation) was reached within 3 days. The validity criterion that the degradation should be ≥ 60% after 14 d was fulfilled.
Stages of Biodegradation: The adaptation phase changed to degradation phase within 2 days (deg-radation > 10%) and the biodegradation came to a maximum of 84% on day 26 (Table 3, Figure 1).

Results of the Toxicity Control
In the toxicity control the biodegradation achieved 40% after 14 days (Table 3,Figure 1). After 28 days the biodegradation came to 43%. The validity criterion that the test item should not inhibit the biodeg-radation of the reference item was fulfilled.

Course and Stages of Biodegradation of Functional Control and Test Item
The biodegradation of the test item is shown in Table 1 and graphically presented in Figure 1 in com-parison to the readily degradable functional control and the toxicity control. Both test item replicates did not reach the 10% level (beginning of biodegradation) within the 28-day-period of the study. The mean biodegradation on day 28 was 1%.

After a test period of 28 days, the test item is classified as not readily biodegradable within the 28 day period of the study.

Key result

Parameter:

ThOD

Value:

2.34 mg O2/g test mat.

Results with reference substance:

The pass level for ready biodegradation (≥ 60% degradation) was reached within 3 days. The validity criterion that the degradation should be ≥ 60% after 14 d was fulfilled.
Stages of Biodegradation: The adaptation phase changed to degradation phase within 2 days (degradation > 10%) and the biodegradation came to a maximum of 84% on day 26.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The test item is classified as not readily biodegradable within the 28 day period of the study.

Executive summary:

The ready biodegradability of the test item Diethylsulphate, compound with 2-(heptadec-8-enyl)-4,5-dihydro-1H-imidazole-1-ethanol (1:1) was determined with non-adapted activated sludge in the Manometric Respirometry Test for a period of 28 days. The study was conducted according to OECD guideline 301 F.

The test item is classified as not readily biodegradable within the 28 day period of the study.

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater