Cyclohexadecen-1-one

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Version / remarks:

(1984)

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: Ultrasonic treatment for 15 minutes at room temperature followed by stirring for 24 h.

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Name and location of sewage treatment plant where inoculum was collected: Municipal sewage treatment plant of Sarstedt, Germany
- Preparation of inoculum for exposure: The sludge was washed twice with autoclaved tap water and adjusted corresponding to a dry weight of 4.0 g/L ± 10 %.
- Initial biomass concentration: 4.29 g/L dw

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Test temperature:

21.2 °C

pH:

7.0 (sludge)

Nominal and measured concentrations:

Nominnal concentration: control, 1000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 500 mL Erlenmeyer flasks
- Fill volume: 500 mL
- Aeration:permanent
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 2
- No. of vessels per toxicity control (replicates): 1 (three test concentrations)

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Synthetic waste water according to OECD-Guideline 209

EFFECT PARAMETERS MEASURED: Respiration inhibition

TEST CONCENTRATIONS
- Range finding study: yes
- Test concentrations: 10, 100, 1000 mg/L
- Results used to determine the conditions for the definitive study: no respiration inhibition in the highest test concentration

Reference substance (positive control):

yes

Remarks:

Copper (II) sulphate pentahydrate

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Details on results:

The test item was insoluble and swam on the surface. After ultrasonic treatment a white turbidity occurred and drops formed on the surface.

Results with reference substance (positive control):

EC50 = 101 mg/L

Table 1: Respiration Rates and Inhibition of Respiration of Test and Reference Item Concentrations

	Concentration [mg/L]	Respiration rate [mg02/L•h]	Inhibition [%]
Test item	1000	23.6	16
Control 1		28.4
Control 2	—	28.0	—
Reference item	180	7.6	73
	100	13.2	53
	58	21.2	25

An inhibition of 16% at the highest tested dose, was assessed as not significant.

Validity criteria fulfilled:

yes

Conclusions:

The test item is not toxic at concentrations up to 1000 mg/L to activated sludge of a municipal sewage treatment plant.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

1 000 mg/L

Additional information

One acute microorganism toxicity study is available. This study was performed according to OECD guideline 209 and in compliance with GLP. Activated sludge of a municipal sewage treatment plant was exposed over a period of 3 hours to a nominal concentration of 1000 mg test item/L. The test item showed no inhibitory effects on microorganisms. This study is considered reliable and relevant (Klimisch 1) and is suitable for use as a key study.