Ammonium undecafluorohexanoate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

05 - 08 Jun 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: control, 100 mg/L
- Sampling method: Samples were taken at test start and test end. The samples were taken from an additional container. Algae cells were removed by centrifugation (3000 rpm, 10 min). Approximately 10 mL were sampled at test start and 9 mL at test end.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The test sample of 0.16 g was mixed in 800 mL of test medium and it was stirred for 1 min to prepare the dissolved test solution of 200 mg test substance/L corresponding to 100 mg a.i./L.
- Eluate: no
- Differential loading: no
- Controls: yes, test medium control

Test organisms (species):

Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)

Details on test organisms:

TEST ORGANISM
- Common name: green algae
- Strain: ATCC 22662
- Source (laboratory, culture collection): American Type Culture Collection (supplied: 30 Jun 1995)

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test temperature:

22.3 - 22.5 °C

pH:

7.8 - 8.3

Nominal and measured concentrations:

Nominal: control, 100 mg/L
Measured: < LOD, 98.8 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 300 mL Erlenmeyer flask (with gas-permeable Silicosen)
- headspace, fill volume: Fill volume: 100 mL, Headspace: 200 mL
- Aeration: constantly shaken at 100 rpm
- Initial cells density: 0.75E+04 cells/mL
- Control end cells density: 150E+04 cells/mL
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes, according to guideline

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: purified water, according to guideline
- Culture medium different from test medium: no, same as test

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: no
- Photoperiod: continuous illumination
- Light intensity and quality: fluorescent light with a wavelength range of 400-700 nm; nominal 90 µmol*m-2*s-1 ± 20%

EFFECT PARAMETERS MEASURED
- Determination of cell concentrations: particle counter (Model Coulter Z2) every 24 h
- Other: Microscopic observation of cell conditions at test start and end.

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

Reference substance (positive control):

yes

Remarks:

Periodically conducted with potassium dichromate (Test period 22-25 May 2017)

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

< 100 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): No abnormalities of cell shape were observed in the control and in the treatment.

Results with reference substance (positive control):

- Results with reference substance valid? yes
- EC50: ErC50 (72 h): 1.3 mg/L
- Other: Test period 22 - 25 May 2017

Reported statistics and error estimates:

The NOEC was estimated by F-test, Student's t-test (p<0.05).

The EC10 is not reported in the test report but it can be derived based on the raw data since the mean inhibition of growth is 1.3% and clearly below 10%.

Table 1: Growth rate and growth inhibition

Nominal concentration	No.	Growth rate (0-3 d)	Growth inhibition rate [%]
Control	A	1.76	-
	B	1.76	-
	C	1.76	-
	D	1.75	-
	E	1.77	-
	F	1.75	-
	Mean	1.76	-
	S.D.	0.00869	-
100 mg/L	A	1.73	1.5
	B	1.73	1.6
	C	1.74	3.1
	D	1.70	3.0
	E	1.76	0.026
	F	1.75	0.64
	Mean	1.73	1.3
	S.D.	0.0181	1.0

Table 2: Cell concentrations

		Cell concentration [E+04 cells/mL]
Nominal concentration	No.	0 h	24 h	48 h	72 h
Control	A	0.75	5.1	25	150
	B	0.75	5.0	27	150
	C	0.75	5.3	26	150
	D	0.75	4.9	27	140
	E	0.75	5.1	27	150
	F	0.75	5.3	26	140
	Mean	0.75	5.1	26	150
	S.D.	0	0.15	0.48	3.8
100 mg/L	A	0.75	5.1	26	130
	B	0.75	5.0	27	130
	C	0.75	5.0	27	140
	D	0.75	5.1	26	120
	E	0.75	5.0	28	150
	F	0.75	5.1	26	140
	Mean	0.75	5.0	27	140
	S.D.	0	0.064	0.84	7.3

At 0 h the cell concentrations are based on measured cell concentration in pre-culture.

Validity criteria

The mean coefficient of variation for section-by-section specific growth rates in the control cultures is 8.3%. The coefficient of variation of average specific growth rates during the whole test period in replicate control cultures is 0.49%. The biomass in the control cultures increased by a factor of 187. All validity criteria were met.

Validity criteria fulfilled:

yes

Description of key information

ErC50 (72 h) > 100 mg a.i./L (nominal; OECD 201)
ErC10 (72 h) > 100 mg a.i./L (nominal; OECD 201)

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L

EC10 or NOEC for freshwater algae:

100 mg/L

Additional information

One experimental study according to OECD 201 (GLP) is available investigating the effects of ammonium undecafluorohexanoate (CAS 21615-47-4) on growth of freshwater algae Pseudokirchneriella subcapitata. The study was performed as a limit test with a substance concentration of 200 mg test item/L corresponding to 100 mg a.i./L. Six replicates were tested for the control and the treatment and the cell concentration was measured every 24 h. At the end of exposure a mean growth inhibition of 1.3% was recorded. Based on statistical analysis this effect is statistically significant (p<0.05). Thus, a NOErC (72 h) cannot be derived but is < 100 mg a.i./L. However, the ErC10 should be used instead for the assessment of chronic toxicity since it also reflects and takes the biological variance into account. The ErC10 was derived to be > 100 mg a.i./L. No acute effects described by the ErC50 were recorded as well (ErC50 (72 h) > 100 mg a.i./L).