1-Ethyl-3-methylimidazolium Diethyl Phosphate

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:

18-4-2019 to 03-09-2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: Chemicals - ready biodegradability - Manometric respirometry test

Version / remarks:

(GB/T 21801-2008)

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: The Guidelines for the testing of Chemicals, Degradation and Accumulation

Version / remarks:

2nd edition, Bejing, China Environmental Press, 2013

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: The guidelines for the testing of chemicals

Version / remarks:

SEPA (HJ/T 153-2004)

Test guideline 4

Qualifier:

equivalent or similar to guideline

Guideline:

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

Version / remarks:

July 1992

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

1-Ethyl-3-methylimidazolium Diethyl Phosphate

Cas Number:

848641-69-0

Molecular formula:

C6H11N2 C4H10O4P

IUPAC Name:

1-Ethyl-3-methylimidazolium Diethyl Phosphate

Test material form:

liquid

Details on test material:

Batch No 187-9-113-Y
Expiry date: 2021-1-30

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch number of test material: 187-9-113-Y
- Expiration date of the lot/batch: 2021-01-30
- Purity test date: 2019-03-06


STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: closed container, dry and cool place, well ventilated

Test substance stock solution was prepared by mixing 1.0225 g of test substance with mineral medium and fill up to 100 ml.

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge: Sludge originated from a sewage treatment plant with predominantly domestic sewage (Nanjing Tiebei Sewage treatment plant, Batch No.: AS20190423)

- Preparation of inoculum for exposure: Sludge was washed with basal mineral medium by settling the sludge in a graduate cylinder, decanting the supernatant liquid, replacing with fresh basal mineral medium, aerating and settling. The above process was repeated 3 times and the sludge was aerated until use.
- Pretreatment: Before use, the sludge was centrifuged (5000 r/min, 10 minutes) and the supernatant liquid decanted. Thereafter, a small amount of the washed sludge was weighed and then dried at 100°C until the weight of the dried sludge did not change significantly anymore. Then the dry weight percentage of suspended solids of the activated sludge was calculated (5.63%). Finally 3.55 g wet sludge after centrifugation was mixed with 50 ml basal mineral medium to obtain an activated sludge with a mixed liquid suspended solids level of 4 g SS/L. The microbial inoculum concentration was 30 mg/L.

- Initial cell/biomass concentration: Cell density was determined to be 4.4x10-7 CFU/L using microscope.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

44.9 mg/L

Based on:

ThOD

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium:
Stock solution A:
8.56 g KH2PO4
21.7 g K2HPO4
33.39 g NA2HPO4*2H2O
0.51 g NH4CL

in 1 litre deionized water.

Stock solution B: 27.45 g CaCl2 in 1 l deionized water.

Stock solution C: 22.5 g MgSO4*7H2O in 1 l deionized water.

Stock solution D: 0.25 g FeCl3*6H2O in 1 l deionized water.

Basal stock medium: 10 ml Stock solution A in 800 ml deionized water, addition of 1 ml each of solution B, C and D, fill up to 1 litre.



- Additional substrate:
- Test temperature: 22°C +/- 1°C
- pH: 7.2 to 7.67, measured at test start and end in each bottle
- pH adjusted: no
- Suspended solids concentration: 30 mg/L
- Continuous darkness: yes
- Other:

TEST SYSTEM
- Culturing apparatus: closed glas vessel (510 ml) with OxiTop BOD meter, final test solution volume: 250 ml
- Number of culture flasks/concentration: 2
- Details of trap for CO2: absorption by NaOH
- Other: All vessels contained a Teflon coated magnetic stir bar. After equipment assembly stirrer was started and the equipment was checked for air-tightness. Vessels were kept at 22°C in the dark.


CONTROL AND BLANK SYSTEM
- Inoculum blank: 2 vessels containing inoculum only
- Procedure control: 1 vessel containing reference substance (40 mg/L) and inoculum
- Toxicity control: 1 vessel containing test substance (44.9 mg/l), reference substance (40 mg/L) and inoculum
- Other:

STATISTICAL METHODS:

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

Test performance:

Biodegradation of the toxicity control was 50.3% in 14 days indicationg that there is no inhibitory effect ot the test item.

% Degradation

Key result

Parameter:

% degradation (O2 consumption)

Value:

35

Sampling time:

28 d

BOD5 / COD results

Results with reference substance:

Biodegradation of the reference substance, sodium benzoate, reached 97% within 14 days.

Any other information on results incl. tables

see attachments

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Executive summary:

The ready biodegradability of the test item was determined in a 28-d oxygen consumption test (OECD 301F) using activated sludge from a domestic waste water treatment plant. The initial concentration of the test item was 44.9 mg/l, the inoculum concentration was 30 mg/L.

Biodegradation of the reference substance, sodium benzoate, reached 97% within 14 days. Biodegradation of the toxicity control was 50.3% in 14 days indicating that there is no inhibitory effect ot the test item.

Under the test conditions the test substance was degraded by 35% after 28 days.