1-(5,6,7,8-tetrahydro-2-naphthyl)ethan-1-one

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:

20 October 2017 - 21 November 2017

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 D (Ready Biodegradability: Closed Bottle Test)

Version / remarks:

17 July 1992

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

1-(5,6,7,8-tetrahydro-2-naphthyl)ethan-1-one

EC Number:

212-266-7

EC Name:

1-(5,6,7,8-tetrahydro-2-naphthyl)ethan-1-one

Cas Number:

774-55-0

Molecular formula:

C12H14O

IUPAC Name:

1-(5,6,7,8-tetrahydronaphthalen-2-yl)ethan-1-one

Test material form:

liquid

Details on test material:

Appearance: Colourless to pale yellow liquid

Specific details on test material used for the study:

The test item is insoluble in water.
Physical appearance: colourless to pale yellow liquid
Storage conditions: at room temperature protected from light, container flushed with nitrogen.

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of activated sludge: secondary effluent, freshly obtained from a municipal sewage treatment plant ('Waterschap Aa en Maas', 's-Hertogenbosch, The Netherlands)
- Pretreatment: Secondary effluent was filtered through a coarse filter paper; the first 200 mL were discarded.
- Storage conditions: aerated
- Concentration of sludge: not indicated, 4 mL filtrate of secondary effluent per litre of final volume was used

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

1 mg/L

Based on:

test mat.

Initial test substance concentration 2

Initial conc.:

3 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: according to OECD guideline 301
- Test temperature: 22-23°C
- pH: 7.5 (at the start of the test)
- pH adjusted: no
- Continuous darkness: yes
- Other: Oxygen concentration in the test solutions was between 9.31 and 9.41 mg/L at the start of the test and between 7.45 and 7.84 mg/L at the end of the test. The O2 depletion during the test in the inoculum blank was 1.42 mg/L.

TEST SYSTEM
- Culturing apparatus: 250-300 mL BOD bottles with glass stoppers
- Number of culture flasks/concentration: 2
- Measuring equipment: oxygen meter

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes, containing only inoculum
- Abiotic sterile control: no
- Toxicity control: yes, containing reference ite, test item (1 mg/L) and inoculum
- Other: procedure control, containing only reference item and inoculum

STATISTICAL METHODS: no statistical analysis was applied, a figure of more than 10% biodegradation was considered biologically relevant.

Reference substance

Reference substance:

acetic acid, sodium salt

Remarks:

Purity: 99.5%

Results and discussion

Test performance:

- In the toxicity control more than 25% biodegradation occurred within 14 days (29%, based on ThOD), showing that the test item did not inhibit microbial activity.

% Degradation

% Degradation 1

Key result

Parameter:

% degradation (O2 consumption)

Value:

5

Sampling time:

28 d

Remarks on result:

other: 1 mg test item/L

% Degradation 2

Key result

Parameter:

% degradation (O2 consumption)

Value:

6

Sampling time:

28 d

Remarks on result:

other: 3 mg test item/L

Details on results:

- No biologically relevant biodegradation was observed during the 28-day test period. Biodegradation in individual bottles was 4 and 5% for the test solution at 1 mg test item/L and 6% in both test solutions at 3 mg test item/L.

BOD5 / COD results

Results with reference substance:

The reference item biodegraded for 74% after 14 days.

Any other information on results incl. tables

Table 1 Mean Values of Oxygen Depletion at Different Points in Time

Test medium	Concentration	Oxygen depletion (mg O2/L) after X days^a)
	(mg/L)	7	14	21	28
Procedure control A	2	1.08	1.06
Procedure control B	2	1.06	1.24
Test item low A	1	0.14	-0.01	-0.04	0.10
Test item low B	1	-0.08	0.00	0.09	0.13
Test item high A	3	-0.04	0.24	0.57	0.52
Test item high B	3	0.07	0.33	0.41	0.47
Toxicity control A	2 / 1^b)	1.09	1.31
Toxicity control B	2 / 1^b)	1.16	1.17
^a): Corrected for oxygen depletion in the blank control (mean value).
^b): Toxicity control contains sodium acetate andFLORANTONE T.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

In the closed bottle test, performed according to OECD 301D and GLP, the test substance was not readily biodegradable (5 and 6% in test solutions at 1 mg test item/L and 3 mg test item/L, respectively).