C10-14-alkyl-1-(ethenyloxy)-

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:

22 February to 8 May 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source of test material: Kyoeisha Chemical Co., Ltd
- Lot/batch No.of test material: 7080101
- Expiration date of the lot/batch: 1 August 2019
- Purity test date: 1 August 2017

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: 20-25 0C (Ambient). In original container as supplied by the Sponsor (tightly closed and away from heat or sunlight)
- Stability under test conditions: Assumed stable for the duration of the test
- Solubility and stability of the test substance in the solvent/vehicle: Low solubility in water (<1.0 mg/L). Stability of the test item in aqueous medium, not performed.
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: None

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: None, test item added as supplied to aqueous medium.

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure):

Secondary effluent from the JRF Sewage Treatment Plant treating predominantly domestic sewage was used as the inoculum. The Secondary effluent was filtered through a Whatman No. 1 filter paper. The inoculum was pre-conditioned by aerating at 22 ± 2 °C (in the dark) for 6 days.

The Inoculum was analysed for microorganism concentration and confirmed as 2.29 x 104 CFU/mL.

Duration of test (contact time):

28 d

Initial conc.:

2.24 mg/L

Based on:

test mat.

Remarks:

in mineral medium

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- Composition of medium:
Preparation of Stock Solution for Mineral Medium: The stock solutions A, B, C and D for mineral medium were prepared in Milli-Q water as described below:
Stock Solutions Chemicals used Quantity (g) Final volume (mL)
A Potassium dihydrogen orthophosphate 0.850 100
Dipotassium hydrogen orthophosphate 2.175
Disodium hydrogen orthophosphate dihydrate 3.340
Ammonium chloride 0.050
B Calcium chloride dihydrate 3.640 100
C Magnesium sulphate heptahydrate 2.250 100
D Iron (III) chloride hexahydrate 0.0250 100
The pH of stock solution A was 7.44.

Preparation of Mineral Medium
Mineral Medium for Stock Solution (mL) Capacity of Conical Flask (L) Diluted With Volume of Diluents (mL)
A B C D

Inoculum Blank (IB) 4 4 4 4 5 Milli-Q water 3984
Test Solution (TS) 4 4 4 4 5 3984
Procedure Control (PC) 4 4 4 4 5 3984
Toxicity Control (TC) 2 2 2 2 2 1992
Test Blank (TB) 4 4 4 4 5 3984
The mineral medium was strongly aerated for 20 minutes and allowed to stand for 20 h at 22 ± 2 C. All operations were performed in a horizontal laminar flow under aseptic conditions.

- Additional substrate: None
- Solubilising agent (type and concentration if used): None
- Test temperature: All test bottles were incubated at 22 ± 2 ºC in a BOD incubator.
- pH: The pH of stock solution A was 7.44.
- pH adjusted: no
- Aeration of dilution water: The mineral medium was strongly aerated for 20 minutes and allowed to stand for 20 h at 22 ± 2 C. All operations were performed in a horizontal laminar flow under aseptic conditions.
- Suspended solids concentration: The Inoculum was analysed for microorganism concentration and confirmed as 2.29 x 104 CFU/mL.
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 300 mL capasity conical flask
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: The mineral medium was strongly aerated for 20 minutes and allowed to stand for 20 h at 22 ± 2 C. All operations were performed in a horizontal laminar flow under aseptic condition.
- Measuring equipment: Dissolved oxygen was measured using DO meter (Model: HQ-40d, Make Supplier: HACH – USA)
- Test performed in closed vessels due to significant volatility of test substance: No
- Test performed in open system: No

SAMPLING
- Sampling frequency: The inoculum blank, test blank, test solution and procedure control were dispensed into their respective pre-labeled BOD bottles (capacity: 300 mL) in duplicate for analysis of DO on day 0, 7, 14, 21, and 28. The toxicity control was dispensed into its respective pre-labeled bottles in duplicated for day 0, 7, and 14. The day zero samples were immediately analysed for DO after dispensing.
- Sampling method: Dissolved oxygen was measured using DO meter on day 7, 14, 21, and 28. All test bottles were incubated at 22 ± 2 ºC in a BOD incubator.
- Sample storage before analysis: No

CONTROL AND BLANK SYSTEM
- Inoculum blank: Bulk Solution of Inoculum Blank: The inoculum blank was prepared by mixing 4.0 mL inoculum with 3996 mL of mineral medium in a conical flask of 5 L capacity. The solution was mixed thoroughly. The mean values of DO in the inoculum blank were measured on day 0, 7, 14, 21, and 28.

Bulk Solution of Procedure Control
The procedure control was prepared by mixing 4.0 mL stock solution of Potassium hydrogen phthalate and 4.0 mL of inoculum to 3992 mL of mineral medium in a conical flask of 5 L capacity. The solution was mixed thoroughly. The final concentration of reference substance in mineral medium was 2.03 mg/L.

- Toxicity control: Bulk Solution of Toxicity Control:
The toxicity control was prepared by mixing 2.0 mL stock solution of Potassium hydrogen phthalate, 1.0 mL stock solution of test item and 2.0 mL of inoculum to 1995 mL of mineral medium in a conical flask of 2 L capacity. The solution was mixed thoroughly. The final concentration was 2.03 mg/L of reference substance and 2.24 mg/L of test item in mineral medium. The mean DO value for the toxicity controls were measure on days 0, 7, and 14.

STATISTICAL METHODS: None

Reference substance:

other: Potassium hydrogen phthalate

Key result

Parameter:

% degradation (DOC removal)

Remarks:

Procedure control

Value:

82.55

Sampling time:

28 d

Key result

Parameter:

% degradation (DOC removal)

Remarks:

Test solution

Value:

49.06

Sampling time:

28 d

Details on results:

Treatment % Degradation (Based on ThOD) on day
7 14 21 28

Procedure Control 59.15 74.21 84.26 82.55
Test Solution 10.83 32.32 41.11 49.06
Toxicity Control 27.37 44.01 - -

Results with reference substance:

See below summary table

Treatment	Criteria	Results	Conclusion
Inoculum Blank	Change in DO over 28 day must be ≤ 1.5 mg/L	0.99	Pass
Test Blank		1.18
Procedure Control	Degradation must be > 60% of ThOD within 14 days	74.21	Pass
Test Solution	Residual oxygen over 28 day must be > 0.5 mg/L	4.17	Pass
	Degradable, if oxygen consumption exceeds > 60% of ThOD over 28 day	49.06	Not readily biodegradable
Toxicity Control (Potassium hydrogen phthalate)	Toxic, if % degradation < 25% within 14 days	44.01	Pass – Not toxic

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Remarks:

Non-toxic to microorganisms in the inoculum

Conclusions:

The percent biodegradation data concluded that C10-C14 alkyl ether is not readily biodegradable. The test item showed a maximum degradation of 49.06% on day 28 (i.e. outside guideline pass levels of 70% removal of DOC and 60% of ThOD), whereas the reference substance exhibited a normal pattern of degradation (up to 82.55%) within 28 days.
The percent degradation by toxicity control was greater than 25% after 14 days. Therefore, the test item is regarded as not readily biodegradable and non-toxic to microorganisms in the inoculum.

Description of key information

The substance was found to be not readily bio-degradable.

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable, not fulfilling specific criteria

Type of water:

freshwater