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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:

2020-10-20 to 2021-01-21

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2021

Report date:

2021

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Reaction mass of 2-(3a,4,5,6,7,7a-hexahydro-1H-4,7-methanoinden-5-yloxy)ethyl acrylate and 2-(3a,4,5,6,7,7a-hexahydro-1H-4,7-methanoinden-6-yloxy)ethyl acrylate

Molecular formula:

C15 H20 O3

IUPAC Name:

Reaction mass of 2-(3a,4,5,6,7,7a-hexahydro-1H-4,7-methanoinden-5-yloxy)ethyl acrylate and 2-(3a,4,5,6,7,7a-hexahydro-1H-4,7-methanoinden-6-yloxy)ethyl acrylate

Test material form:

liquid

Details on test material:

- Name: 2-Propenoic acid,2-[[3a,4,5,6,7,7a-hexahydro-4,7-methano-1H-inden-5(or 6)-yl]oxy]ethyl ester
- CAS No.: 68169-12-0 (outside EU)
- EC Name: Reaction mass of 2-(3a,4,5,6,7,7a-hexahydro-1H-4,7-methanoinden-5-yloxy)ethyl acrylate and 2-(3a,4,5,6,7,7ahexahydro-1H-4,7-methanoinden-6-yloxy)ethyl acrylate
- EC Number: 951-956-9
- Batch No.: OX8J0799
- Molecular Weight: 248.32 g/mol
- Physical State: liquid
- Colour: clear
- Active Components: 98.52% active components (different isomers), 1.48% 2-Cyclopenta-1,3-dienyloxyethan-1-ol
- Purity: 98.52%
- Expiry Date: 17 September 2023
- Storage Conditions: room temperature
- Safety Precautions: The routine hygienic procedures were sufficient to assure personnel health and safety.

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

Inoculum of the aqueous phase of non-adapted activated sludge. The activated sludge was washed twice with chlorine free tap water. After the second washing the settled sludge was resuspended in mineral salts medium and was maintained in an aerobic condition by aeration with CO2 free air for two days before test start. 4.92 mL/L of this mixture were used to initiate inoculation (25.0 mg/L dw).

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

15 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

The necessary amounts of ultrapure water, mineral salts medium and inoculum was placed in each incubation vessel. The vessels were aerated for 24 h with CO2 free air. After 24 h the CO2 adsorption vessels were connected to the air outlets of the incubation vessels via a series of 3 gas wash bottles, each containing 100 mL of a 0.0125 mol/L Ba(OH)2 solution.
The test and reference item were weighed out. The test item was weighed into small beakers. A defined amount of ultrapure water was added to the test item and treated with ultrasound for half an hour. The test item dispersions and the reference item were transferred to the respective incubation vessels with ultrapure water. The vessels were made up to 3 L with ultrapure water and connected to the system for the production of CO2 free air.
On day 28, 1 mL 37 % HCl was added to each of the vessels. Aeration was continued for further 4 h and the quantity of CO2 released was determined.
Determination of CO2 was carried out by titration subsequent to complete adsorption of the released CO2 in an alkaline solution (0.0125 mol/L Ba(OH)2). For each titration the first gas wash bottle was removed and a new bottle was connected to the last one. Back titration of the residual Ba(OH)2 with 0.05 N HCl was carried out three times a week during the first ten days and thereafter twice weekly. On day 28 the pH of all solutions was measured prior to
acidification.

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

% Degradation

Key result

Parameter:

% degradation (CO2 evolution)

Value:

28

Sampling time:

28 d

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Both test item replicates did not reach the 60 % pass level within 28 days. The mean biodegradation on day 28 was 28 %. Under the test conditions 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 Reaction mass of 2-(3a,4,5,6,7,7a-hexahydro-1H-4,7-methanoiden-5-yloxy)ethyl acrylate and 2-(3a,4,5,6,7,7a-hexahydro-1H-4,7-methanoiden-6-yloxy)ethyl acrylate was determined with a non-adapted activated sludge over a test period of 28 days in the Modified Sturm Test.

The biodegradation of the test item was followed by titrimetric analysis of the quantity of CO2 produced by the respiration of bacteria. The degradation was stopped on day 28 by acidification of the test solutions. The last titration was made on day 29 after residual CO2 had been purged from the test solutions over a period of 24 hours. The percentage CO2 production was calculated in relation to the theoretical CO2 production (ThCO2) of the test item.

To check the activity of the test system sodium benzoate was used as functional  control. The percentage degradation of the functional control reached the pass level of 60 % within 6 days and a maximum biodegradation of 94 % on day 28.

In the toxicity control containing both test and reference item a biodegradation of 54 % was determined within 14 days, with 61 % after 28 days. The biodegradation of the reference item was not inhibited by the test item in the toxicity control.

Both test item replicate did not reach the 60 % pass level within 28 days. The mean biodegradation on day 28 was 28 %. Under the test conditions the test item is classified as not readily biodegradable within the 28 day period of the study.