4''-ethyl-2'-fluoro-[1,1':4',1''-terphenyl]-4-methanol

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:

2018-01-10 to 2018-04-05

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

adopted on March 23, 2006; Annex 5 corrected: July 28, 2011

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Version / remarks:

Commission Regulation (EU) 2016/266 of 7 December 2015 amending, for the purpose of its adaptation to technical progress, Regulation (EC) No 440/2008 laying down test methods pursuant to Regulation (EC) No 1907/2006 of the European Parliament and of the Council on the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Remarks:

The test item concentration in the reconstituted water had low water solubility (<0.011 mg/L), thus, the compound cannot be detected with standard analytical methods.

Vehicle:

yes

Remarks:

reconstituted water

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A stock preparation with a test item concentration of 100 mg/L was freshly prepared. For that purpose, the test item was weighed in a calibrated flask and vehicle was added. The preparation was stirred with a magnetic stirrer for 24 hours. Then the formulation was passed through a filter membrane (pore size: 0.2 µm). The filtrate was used for the study. The pH value was not adjusted.

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Common name: Unicellular green algae
- Strain: 61.81 SAG
- Source: „Pflanzenphysiologisches Institut der Universität Göttingen“, Germany.
- Method of cultivation: The permanent algae cultures, the pre-culture and the algae cultures of the study were cultivated in an air-conditioned room with a water temperature of 21.0 – 24.0 °C, controlled at ± 2 °C. For cultivation, 300 mL Erlenmeyer flasks filled with 100 mL algae suspension were covered with air permeable stoppers. The cultures were shaken continuously at about 120 rpm and lit between 4440 and 8880 Lux. Fluorescent tubes installed above the flasks served for lighting.

ACCLIMATION
- Acclimation period: 72-h
- Culturing media and conditions: same as test
- Any deformed or abnormal cells observed: no

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Post exposure observation period:

-

Hardness:

24 mg/L as CaCO3 (calculated)

Test temperature:

24.4 to 25.3 °C

pH:

7.90 to 8.92

Nominal and measured concentrations:

Nominal concentrations: 100.0 mg/L
No measured concentration.

Details on test conditions:

TEST SYSTEM
- Test vessel: 300 mL Erlenmeyer flasks
- Type: open
- Material, size, headspace, fill volume: 300 mL Erlenmeyer glass flasks filled with 100 mL cell suspension
- Aeration: no
- Initial cells density: 10 000 cells per mL
- Control end cells density: 1 756 338 cells per mL
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reconstituted water according to OECD TG 201
- Culture medium different from test medium: no

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: no
- Light intensity and quality: The mean light intensities were 7544 Lux ± 2.8 % and 7298 Lux ± 2.6 % prior to and at the end of the exposure period, respectively.

EFFECT PARAMETERS MEASURED:
- Determination of cell concentrations: electronic particle counter

TEST CONCENTRATIONS
- Nominal test concentration: 100 mg/L

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: >0.011 mg/L (limit of water solubility)

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: >0.011 mg/L (limit of water solubility)

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: >0.011 mg/L ( (limit of water solubility)

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Yield

Remarks on result:

other: >0.011 mg/L ( (limit of water solubility))

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Yield

Remarks on result:

other: >0.011 mg/L (limit of water solubility)

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Yield

Remarks on result:

other: >0.011 mg/L (limit of water solubility)

Details on results:

No significant effect on growth of the algae was observed at a nominal concentration of 100 mg/L, i.e. up to the maximum water solubility.

The EC values exceeded the water solubility of <0.011 mg/L (nominal >100 mg/L) and, thus, could not be determined in this study.

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): no
- Unusual cell shape: no
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no

Results with reference substance (positive control):

The test item (Potassium dichromate) showed 72h EC50 of 0.91 mg/L for growth rate and 0.48 mg/L for yield. The EC50 for growth rate and yield obtained in this study are in the range of ± two standard deviation of the current historical means.

Therefore, this study confirms the sensitivity and reliability of the test system used in the test facility.

Table 1: Algal Growth Measurement - Algal biomass (cell number) after 24, 48 and 72 hour exposure

Nominal concentration [mg/L]		Biomass of algae (Cell number per mL*)
Control		0 hours	24 hours	48 hours	72 hours
		1.0000	6.5340	30.5460	167.6043
		1.0000	6.1713	38.6757	210.6063
		1.0000	5.2920	28.4724	139.7943
		1.0000	5.3910	34.5627	171.3303
		1.0000	5.5746	31.7034	151.6023
		1.0000	5.8896	38.3994	212.8653
	Mean	1.0000	5.8087	33.7266	175.6338
	SD	0.00000	0.48173	4.21530	30.18024
	CV	0.0	8.3	12.5	17.2
100.0		0 hours	24 hours	48 hours	72 hours
		1.0000	5.0094	30.0780	176.1480
		1.0000	5.1507	31.0743	185.2560
		1.0000	5.9517	36.5220	192.9510
		1.0000	5.6520	34.6680	187.5780
		1.0000	5.2884	31.7376	182.8710
		1.0000	5.5557	34.0740	186.9570
	Mean	1.0000	5.4347	33.0257	185.2935
	SD	0.00000	0.34988	2.45668	5.58809
	CV	0.0	6.4	7.4	3.0

*Cell number divided by factor 10000

 

Table 2: Yield after 24, 48 and 72 hour exposure

Nominal concentration [mg/L]		Yield
Control			24 hours	48 hours	72 hours
			5.5340	29.5460	166.6043
			5.1713	37.6757	209.6063
			4.2920	27.4724	138.7943
			4.3910	33.5627	170.3303
			4.5746	30.7034	150.6023
			4.8896	37.3994	211.8653
	Mean		4.8087	32.7266	174.6338
	SD		0.48173	4.21530	30.18024
	CV		10.0	12.9	17.3
100.0			24 hours	48 hours	72 hours
			4.0094	29.0780	175.1480
			4.1507	30.0743	184.2560
			4.9517	35.5220	191.9510
			4.6520	33.6680	186.5780
			4.2884	30.7376	181.8710
			4.5557	33.0740	185.9570
	Mean		4.4346	32.0257	184.2935
	SD		0.34988	2.45668	5.58809
	CV		7.9	7.7	3.0

 

Table 3: Mean specific growth rate after 24, 48 and 72 hour exposure

 

Nominal concentration [mg/L]	Mean specific growth rate
Control		24 hours	48 hours	72 hours
		1.877	1.710	1.707
		1.820	1.828	1.783
		1.666	1.674	1.647
		1.685	1.771	1.715
		1.718	1.728	1.674
		1.773	1.824	1.787
	Mean	1.757	1.756	1.719
	SD	0.0820	0.0625	0.0569
	CV	4.7	3.6	3.3
100.0		24 hours	48 hours	72 hours
		1.611	1.702	1.724
		1.639	1.718	1.741
		1.784	1.799	1.754
		1.732	1.773	1.745
		1.666	1.729	1.736
		1.715	1.764	1.744
	Mean	1.691	1.747	1.741
	SD	0.0641	0.0371	0.0101
	CV	3.8	2.1	0.6

 

Table 4: EC-Values

Parameter (0-72h)	Growth rate	Yield
EC10 95% confidence interval	>0.011 mg/L (nominal >100 mg/L) n.d.	>0.011 mg/L (nominal >100 mg/L) n.d.
EC20 95% confidence interval	>0.011 mg/L (nominal >100 mg/L) n.d.	>0.011 mg/L (nominal >100 mg/L) n.d.
EC50 95% confidence interval	>0.011 mg/L (nominal >100 mg/L) n.d.	>0.011 mg/L (nominal >100 mg/L) n.d.

 

 

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of the present study, an aqueous solution of nominal 100 mg/L of the test item revealed no toxicity to algae.
The 72h EC50, EC20 and EC10 for growth rate and yield were >0.011 mg/L (nominal >100 mg/L) and thus, could not be determined in this study.

Executive summary:

The toxicity of the test item on the growth and growth rate of the green algae of the unicellular green alga,Pseudokirchneriella subcapitataduring exposure period of 72 hours was estimated in a method according to OECD 201 under GLP. For this purpose, exponentially growing cultures ofPseudokirchneriella subcapitatawere exposed to a nominal test item concentration of 100 mg/L. The study comprised of one control group and one test item group with six replicates each. The initial algae cell density in each replicate was 10 000 cells/mL. The growth of the algae was determined over an exposure period of 72 hours and compared with the growth of the control group. The test item concentration in the reconstituted water was not quantified at the start and the end of this study. Because of the low water solubility (<0.011 mg/L), the test item cannot be detected with standard analytical methods and the development of an analytical method with a sufficiently low detection and quantification limit is complex. Due to the absence of any adverse effects at the saturation concentration, the study was performed without analytical concentration verification. No significant effect on growth rate and yield of the algae was observed at a nominal concentration of 100 mg/L, i.e. up to the maximum water solubility. Under the conditions of the present study, an aqueous solution of nominal 100 mg/L of the test item revealed no toxicity to algae. The 72h EC_50, EC₂₀ and EC₁₀for growth rate and yield were >0.011 mg/L (nominal >100 mg/L) and thus, could not be determined in this study

Description of key information

Under the conditions of the present study, an aqueous solution of nominal 100 mg/L of the test item revealed no toxicity to algae.

The 72h EC_50, EC₂₀ and EC₁₀for growth rate and yield were >0.011 mg/L (nominal >100 mg/L) and thus, could not be determined in this study. (reference 6.1.5-1).

Additional information

The toxicity of the test item on the growth and growth rate of the green algae of the unicellular green alga,Pseudokirchneriella subcapitataduring exposure period of 72 hours was estimated in a method according to OECD 201 under GLP. For this purpose, exponentially growing cultures ofPseudokirchneriella subcapitatawere exposed to a nominal test item concentration of 100 mg/L. The study comprised of one control group and one test item group with six replicates each. The initial algae cell density in each replicate was 10 000 cells/mL. The growth of the algae was determined over an exposure period of 72 hours and compared with the growth of the control group. The test item concentration in the reconstituted water was not quantified at the start and the end of this study. Because of the low water solubility (<0.011 mg/L), the test item cannot be detected with standard analytical methods and the development of an analytical method with a sufficiently low detection and quantification limit is complex. Due to the absence of any adverse effects at the saturation concentration, the study was performed without analytical concentration verification. No significant effect on growth rate and yield of the algae was observed at a nominal concentration of 100 mg/L, i.e. up to the maximum water solubility. Under the conditions of the present study, an aqueous solution of nominal 100 mg/L of the test item revealed no toxicity to algae. The 72h EC_50, EC₂₀ and EC₁₀for growth rate and yield were >0.011 mg/L (nominal >100 mg/L) and thus, could not be determined in this study