3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooct-1-ene

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Only preliminary test.

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test (Carbon and Ammonium Oxidation))

Deviations:

yes

Remarks:

Only a pre-test was performed for an exposure duration 30 min three replicates.

GLP compliance:

no

Analytical monitoring:

yes

Vehicle:

no

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Laboratory culture:
- Name and location of sewage treatment plant where inoculum was collected: Activated sludge obtained from an aeration reactor of a sewage treatment plant receiving predominantly domestic sewage (Kurume central sewage treatment center (Kurume-shi, Fukuoka, Japan)
- Method of cultivation: The activated sludge (5 L) was fed with the synthetic sewage (250 mL) and cultivated for 19.5 h at 20 ± 2 °C under aerobic condition in order to acclimate the test conditions. The activated sludge was then used. Acclimation to the test item was not performed.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

30 min

Test temperature:

20 ± 2 °C

Nominal and measured concentrations:

nominal: control, 1000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Approximately 300 mL glass vessel (test vessel); 102 mL glass incubator bottle
- Type (delete if not applicable): open
- Test solutions: The test sample (160 μL, i.e., 250 mg), the synthetic sewage (8 mL), the purified water (117 mL) and the activated sludge (125 mL) were added to each test vessel.
- Aeration: yes, flow rate 0.5 - 1.0 L/min.
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 2
- Suspended solid concentration: 2330 mg/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: purified water

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): respiration rate after 30 min

TEST CONCENTRATIONS
- Spacing factor for test concentrations: not applicable, limit test

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Duration:

30 min

Dose descriptor:

EC50

Remarks on result:

not measured/tested

Remarks:

Pre-test; no EC50 was calculated

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Relevant effect levels: EC50 (30 min) 10 mg/L

Table 1: Inhibition of respiration

Test solution	Concentration [mg/L]	Oxygen consumption rate [mg O2/L/h]	Percentage inhibition of respiration [%]	Percentage residue of test item [%]
Test substance 1	1000	44.0	8	4
Test substance 2		44.9	6	6
Test substance 3		40.3	16	0
Reference item	4	37.3	22	-
	12	16.5	66	-
	36	7.85	84	-
Blank control 1	-	51.7 (beginning)	-	-
Blank control 2	-	43.9 (end)	-	-

The preliminary test as simple test was valid because the results met validity criteria of the OECD 209 test, and the high recovery rates of the test item were obtained by the pretreatment of the test solution in the recovery test (96.4% and 94.8%).

Validity criteria fulfilled:

not applicable

Reference 2

Endpoint:

activated sludge respiration inhibition testing

Data waiving:

study technically not feasible

Justification for data waiving:

other:

Description of key information

Study technically not feasible.

Additional information

An experimental study according to OECD 209 is technically not possible to be adequately performed. The substance has a vapour pressure of 4640 Pa at 25 °C and it is thus not possible to maintain exposure concentrations constant for the total exposure time of 3 h. An attempt was made to perform this study at a shorter duration of 30 min as recommended in ECHA Guidance R.7b (ECHA, 2017) for volatile substances (Daikin Industries, 2017). A test solution of nominal 1000 mg/L (three replicates) was aerated for 30 min according to OECD 209. This study was performed including chemical analysis by GC/FID to check if the substance is stable during exposure. Recovery rates were 96.4% and 94.8% (n=2) after preparation of the test solutions. After 30 min only 0-6% of the substance was found based on initial concentration. Thus, almost all of the substance evaporated after 30 min. Since it is not possible to perform the study with closed test vessels it was concluded that a main test is technically not possible to be performed since the substance concentration could not be maintained in the test solutions. In this pre-test no inhibition of respiration compared to the control was found after 30 min. The same process of evaporation would also happen at the aeration stage of common sewage treatment plants. Thus, it can be ensured that the test item is not likely to cause any effects on the degradation process of activated sludge microorganisms in sewage treatment plants.