Alcohols, C12-14, ethoxylated

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

effects on growth of green algae

Type of information:

experimental study

Adequacy of study:

key study

Study period:

01 Mar - 26 Mar 2021

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:

2006, corrected 2011

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: all concentrations
- Sampling method: sampling at 0h (fresh solutions) and aftter 24, 48 and 72 h (aged solutions)
- Sample storage conditions before analysis: The samples were mixed with 10 mL acetonitrile and stored deep-frozen (≤ - 18 °C) until analysis.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A stock solution was prepared by adding the necessary amount of test item to a volumetric flask. Test medium was added and the solution was homogenised by stirring on a magnetic stirrer for 1 hour. The solution was observed to be clear and transparent; frothing was observed. Test item concentrations were prepared by dilution with test medium. All lower concentrations of test item solutions were observed to be clear and transparent. Algae were added to each solution individually, targeting nominal cell densities of 0.5 × 104 cells per mL in each solution.

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Strain: SAG 61.81
- Source (laboratory, culture collection): purchased from MBM Sciencebridge GmbH, Göttingen, Germany
- Method of cultivation: The algae are grown semi-continuously in sterile cultures in the laboratory. Old medium is periodically replaced by fresh mineral solution in order to keep the algae in an exponential growth state.

ACCLIMATION
- Acclimation period: 3 to 4 days
- Culturing media and conditions (same as test or not): same

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

22.4 – 23.3 °C

pH:

7.52 - 8.42

Nominal and measured concentrations:

Nominal test item concentrations: 0.0954, 0.305, 0.977, 3.13, 10.0 mg/L
Geometric mean measured test item concentrations: 0.0239, 0.0366, 0.0489, 0.282, 5.60 mg/L (based on 2 representative constituents)

Details on test conditions:

TEST SYSTEM
- Test vessel: Erlenmeyer flasks (glass), nominal volume 100 mL
- Type (delete if not applicable): covered by aluminium caps
- Fill volume: ~50 mL
- Initial cells density: 0.5 × E*4 cells/mL
- Control end cells density: 65.05 × E*4 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes acc. to AAP-Medium (according to Annex 3 of OECD 201)

TEST MEDIUM / WATER PARAMETERS
- Culture medium different from test medium: no
- Intervals of water quality measurement: pH at test start and test end; temperature continously

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod:continous illumination
- Light intensity and quality: 95.0 µEm-2s-1 (mean light intensity)

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: cell densities were determined by a fluorimeter at time points. 0, 24, 48 and 72 h

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: 0.0100, 0.100, 1.00 and 10.0 mg/L
- Results used to determine the conditions for the definitive study: EC50 (72h): >1.00 - < 10.0 mg/L

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.034 mg/L

95% CI:

>= 0.031 - <= 0.036

Nominal / measured:

meas. (geom. mean)

Conc. based on:

other: based on two representative constituents

Remarks:

C12EO2 and C12EO3

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.044 mg/L

95% CI:

>= 0.043 - <= 0.047

Nominal / measured:

meas. (geom. mean)

Conc. based on:

other: based on two representative constituents

Remarks:

based on two representative constituents

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.037 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

other: based on two representative constituents

Remarks:

C12EO2 and C12EO3

Basis for effect:

growth rate

Details on results:

- Exponential growth in the control (for algal test): yes

Results with reference substance (positive control):

- ErC50 (72 h): 1.55 mg/L (NOErC(72 h): 0.320 mg/L)
- Other: test performed Jan 2021

Reported statistics and error estimates:

The NOEC and LOEC were determined by using a multiple comparison method (Williams' test, left sided, for growth rate, Jonckheere-Terpstra test, left sided, for yield). The EC10, 20, 50-values for growth rate and yield were determined by probit analysis using linear maximum likelihood regression and Weibull analysis using linear maximum likelihood regression, respectively.

Table 1: Validity criteria for OECD 201 (2006)

Criterion from the guideline	Outcome	Validity criterion fulfilled
The biomass in the control cultures should have increased exponentially by a factor of at least 16 within the 72-hour test period.	110.25	yes
The mean coefficient of variation for section-by-section specific growth rates (days 0-1, 1-2 and 2-3, for 72-hour tests) in the control cultures must not exceed 35%	8%	yes
The coefficient of variation of average specific growth rates during the whole test period in replicate control cultures must not exceed 7% in tests with Pseudokirchneriella subcapitata and Desmodesmus subspicatus. For other less frequently tested species, the value should not exceed 10%.	1.5%	yes

 

Table 2: Percentage inhibition of growth rate

Nominal conc.	% Inhibition of growth rate
[mg/L]	0 h – 24 h	0 h – 48 h	0 h – 72 h
Control	0.0	0.0	0.0
0.0954	-4.2	-2.7	-1.4
0.305	13.2	16.8	5.8
0.977	118.2	104.5	72.9 *
3.13	≥ 100^1)	214.0	162.5 *
10.0	≥ 100^1)	≥ 100^1)	163.2 *

* Statistically significant different to the control (left-sided, p≤0.05)

¹⁾Due to cell numbers of zero the value was not calculable but was equal to or above 100

 

 

Validity criteria fulfilled:

yes

Remarks:

please see table 1 at "Any other information on results incl. tables"

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

22 - 25 JAN 2008

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

GLP compliance:

no

Remarks:

ISO/IEC 17025

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A stock solution was prepared y sterile filtration (0.45µm). Preparation of water accommodated fractions

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: green algae
- Strain: 86.81 SAG
- Source (laboratory, culture collection): Collection of Algal Cultures, Institute of Freshwater Ecology, University of Göttingen, Göttingen, Germany.
- Method of cultivation: 250 mL flask containing 100 mL sterile OECD medium inoculated with cell material from axenic slope culture

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

22 ± 2°C

Nominal and measured concentrations:

Nominal test substance concentrations: 0.250, 0.500, 1.00, 2.00, 4.00 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 ml galss beakers
- Fill volume: 100 ml
- Initial cells density: 0.5-0.85 µg dw/ml
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: continous illumination
- Light intensity and quality: high pressure sodium lamp. 5000-6000 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: every 24 h by spectrophotometer

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2.5
- Justification for using less concentrations than requested by guideline:
- Range finding study
- Test concentrations: 1, 10 and 100 mg/L
- Results used to determine the conditions for the definitive study: 96% growth inhibition at 100 mg/L, 96% at 10 mg/L and 43% at 1 mg/L

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.778 mg/L

95% CI:

>= 0.707 - <= 0.853

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.25 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.416 mg/L

95% CI:

>= 0.321 - <= 0.487

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.25 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

yield

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.516 mg/L

95% CI:

>= 0.495 - <= 0.54

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

yield

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.312 mg/L

95% CI:

>= 0.266 - <= 0.344

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

yield

Details on results:

- Exponential growth in the control (for algal test): yes

Table 1: Validity criteria for OECD 201 (2006)

Criterion from the guideline	Outcome	Validity criterion fulfilled
The biomass in the control cultures should have increased exponentially by a factor of at least 16 within the 72-hour test period.	>16	yes
The mean coefficient of variation for section-by-section specific growth rates (days 0-1, 1-2 and 2-3, for 72-hour tests) in the control cultures must not exceed 35%	24.3%	yes
The coefficient of variation of average specific growth rates during the whole test period in replicate control cultures must not exceed 7% in tests with Pseudokirchneriella subcapitata and Desmodesmus subspicatus. For other less frequently tested species, the value should not exceed 10%.	2.4%	yes

Table 2: Algal cell growth

Nominal concentration	Mean inibition [%]
Control	0
0.250	1.23
0.500	17.7
1.00	70.6
2.00	79.9
4.00	99.4

 

Validity criteria fulfilled:

yes

Remarks:

please see table 1 at "Any other information on results incl. tables"

Reference 3

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

15 - 18 JUN 1993

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

other: 92/69/EWG

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A stokc solution was prepared by adding 0.1 g test substance to 1 l distilled water.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Strain: SAG 86.81
- Source (laboratory, culture collection): i-house culture, originally obtained from Institut für Wasser-, Boden- und Lufthygiene, berlin, Germany
- Age of inoculum (at test initiation): 3 d

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

pH:

8.6 - 8.8 (start)
8.3 - 8.8 (end)

Nominal and measured concentrations:

Nominal test substance concentrations: 17, 30, 50, 90, 150, 250 µg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: glass beakers
- Initial cells density: 2*E04 cells/ml
- No. of vessels per concentration (replicates): 5
- No. of vessels per control (replicates): 8

GROWTH MEDIUM
- Standard medium used: yes (acc. to guideline 92/69/EWG)


OTHER TEST CONDITIONS
- Light intensity and quality: ca. 8000 lux, white
- Salinity (for marine algae):

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: at 0, 24, 48 and 72 h, fluorometric

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 0.25 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.12 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.05 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.088 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.036 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Test concentration [µg/L]	Cell density [× 10^4/mL]
	Incubation period [h]
	0	24	48	72
0	2	5	19	57
17	2	5	18	53
30	2	5	19	57
50	2	5	19	54
90	2	4	14	45
150	2	4	10	32
250	2	3	9	27

Validity criteria fulfilled:

not specified

Reference 4

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

09 - 13 DEC 2002

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

significant methodological deficiencies

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

1984

Deviations:

no

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

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

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test temperature:

23 ± 2°C

Nominal and measured concentrations:

Nominal test substance concentration: 2 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: glass beakers (250 ml)
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3

GROWTH MEDIUM
- Standard medium used: yes/no
- Detailed composition if non-standard medium was used:

OTHER TEST CONDITIONS
- Photoperiod: continous illumination


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: counting chamber (at 24 ,48 and 72 h)

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Description of key information

ErC50 (72 h): 0.034 mg/L (meas. geom.mean; OECD 201)

ErC10 (72 h): 0.0445 mg/L (meas. geom.mean; OECD 201)

Additional information

One key study on the toxicity of Alcohols, C12-14, ethoxylated to aquatic algae is available. The study design followed OECD guideline 201. Green algae of the species Raphidocelis subcapitata were used as test organisms. The algae were exposed to nominal test substance concentrations of 0.0954, 0.305, 0.977, 3.13, and 10.0 mg/L. The test concentrations were analytically verified by HPLC/MS-MS. The geometric mean measured test item concentrations were 0.0239, 0.0366, 0.0489, 0.282, and 5.60 mg/L (based 2 representative constituents). An ErC10 (72 h) of 0.034 mg/L (geom. mean) was determined at based on the algal growth rate. The ErC50 (72 h) was 0.0446 mg/L (geom. mean) .

 

Comparable results were determined in five available supporting studies. All studies were conducted according to OECD guideline 201 and were performed without analytical dose verification. The determined ErC50 (72 h) values range from >0.25 - 0.52 mg/L (nominal) (NOEC (72 h) 0.0365 - 0.63 mg/L).