2-(4-Bromphenyl)-5-butyl-1,3-dioxane, trans-

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:

26 Mar - 17 Jul 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2-(4-Bromphenyl)-5-butyl-1,3-dioxane, trans-

EC Number:

817-763-8

Cas Number:

1310048-86-2

Molecular formula:

C14H19BrO2

IUPAC Name:

2-(4-Bromphenyl)-5-butyl-1,3-dioxane, trans-

Test material form:

solid

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Municipal sewage treatment plant, D-31137 Hildesheim

- Pretreatment:
The activated sludge was washed twice with autoclaved tap water. After the second washing the settled sludge was filled up with mineral salts medium and was maintained in an aerobic condition by aeration for 2-4 hours. Thereafter the sludge was homogenized with a blender. The supernatant was decanted and maintained in an aerobic condition by aeration with CO2-free air for 6 days. 10 mL/L were used to initiate inoculation.

- Concentration of sludge: 10 mL/L
- Initial cell/biomass concentration: 10^7 - 10^8 CFU/L
- Water: demineralized

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

30 mg/L

Based on:

test mat.

Initial test substance concentration 2

Initial conc.:

50.1 mg/L

Based on:

ThOD

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

Preparation of the test vessels

Based on the calculated oxygen demand, the test concentration of 27 mg/L, corresponding to an oxygen demand of 50.8 mg O2/L in the vessel, was selected.
The test solutions were prepared in measuring flasks and were placed in brown glass bottles as incubation vessels (inoculum control and functional control) or were prepared directly in brown glass bottles (test item and toxicity control):
• two for the inoculum control (C1, C2)
• one for the functional control (R1)
• two for the test item (P1, P2)
• one for the toxicity control (T1)

Separate replicates of test item and toxicity control were prepared for measurement of the pH-value at test start:

• one for the test item (PpH)
• one for the toxicity control (TpH)

- Inoculum control: The inoculated test medium, consisting of the required volumes of mineral medium stock solutions, ultrapure water and inoculum, was prepared in a measuring flask. 250 mL of this solution were filled in the brown glass bottles of the inoculum control, using a 250 mL measuring flask.
- Functional control: The reference item was weighed out and transferred into a measuring flask, the required volumes of mineral medium stock solutions, ul-trapure water and inoculum, were added. 250 mL of this solution were filled in the brown glass bottle of the functional control, using a 250 mL measuring flask.
- Test Item: The test item was weighed out for each replicate and directly trans-ferred into the test vessels with 250 mL of the inoculated test medi-um, using a 250 mL measuring flask.
- Toxicity control: The test item was weighed out and directly transferred into the test vessels with 250 mL of the reference item medium (see above), using a 250 mL measuring flask.

A rubber sleeve with soda lime was hung into the opening of the bot-tles to absorb evolved CO2. The bottles were closed with OxiTop measuring heads and the measuring system was activated.

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

Test performance:

Results of the Functional Control
The pass level of a biodegradation > 60 % was reached on day 4. The validity criterion that the degradation should be > 60 % after 14 d was fulfilled

Results of the Toxicity Control
In the toxicity control the biodegradation achieved 52 % after 14 days. After 28 days the biodegradation came to 56 %. The validity criterion that the test item should not inhibit the biodegradation of the reference item was fulfilled.

% Degradation

Key result

Parameter:

% degradation (O2 consumption)

Value:

1

Sampling time:

28 d

Details on results:

Both test item replicates did not reach the 10 % level (beginning of biodegradation) within the 28 d period of the study. The mean biodegradation on day 28 was 1 %.

Any other information on results incl. tables

Table 1: Biodegradation [%] of the test item in comparison to the functional control and toxicity control

		Biodegradation [%] Study day [d]
	Replicate	7	14	21	28
Test item 27 mg Test Material/L	1	0	0	0	0
Test item 27 mg Test Material/L	2	0	0	2	1
Functional control 30 mg Reference Item/L		78	83	83	84
Toxicity control + 22 mg  Test Material/L + 30 mg Reference Item/L		47	45	45	45

Applicant's summary and conclusion

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 informtion for this endpoint study record was obtained from an experimental study. The OECD GLP criteria were met and the methods applied are fully compliant with OECD TG 301F. The test item is classified as not readily biodegradable within the 28 day period of the study.