2-ethoxyethyl methacrylate

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:

1997-12-15 to 1998-01-13

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Version / remarks:

04 April 1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

adopted 07 June 1984

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 0, 4.3, 9.4, 20.7, 45.5, 100, 200 mg/L; at beginning and end of the test
- Sample storage conditions before analysis: no data

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Preliminary test: Preparation of a stock solution (106.9 mg of test item in 1.069 L dilution water) by stirring for 23.5 h in darkness
- Definitive test: Preparation of a stock solution (408 mg in 2.044 L dilution water) by stirring in darkness for 58 h. Resulting concentration: 200 mg/L
- Preparations of test concentrations: dilution of the stock solution by the factor of 2 (100 mg/L) and then 2.2 (45.5, 20.7, 9.4, 4.3 mg/L)

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Common name: green algae
- Strain: Pseudokirchneriella subcapitata CCAP 27814
- Source (laboratory, culture collection): Culture Center of Algae and Protozoa
- Age of inoculum (at test initiation): 4 d pre-culture
- Method of cultivation:
4 d before the test, pre-cultures were prepared by diluting 5 mL of the stock culture in 500 mL dilution water; at the beginning of the test, 50 mL were transferred from the pre-culture and cell numbers were adjusted to 10E04 cells/mL

ACCLIMATION
- Culturing media and conditions (same as test or not): same as test
- Any deformed or abnormal cells observed: no; verified for each culture before use

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

22.75 ± 1.75 °C

pH:

initial: 7.68 - 7.79
final: 7.27 - 7.66

Dissolved oxygen:

initial: 9.1 - 9.6 mg/L
final: 8.9 - 9.1 mg/L

Nominal and measured concentrations:

preliminary test: 0.1 to 100% of saturated solution

definitive test:
nominal: 0, 4.3, 9.4, 20.7, 45.5, 100, 200 mg/L
measured, initial: 0, 4, 8.6, 19.1, 42.4, 92.9, 184.2 mg/L
measured, final: 0, 3.6 (2.65*), 7.75, 17.1, 39.8 (35.1*), 84.3, 170.05 (159.7*) mg/L
*concentrations measured using samples from algae assay.

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 mL glass erlenmeyer flasks containing 50 mL test solution and algae inoculum
- Type (delete if not applicable): closed
- Initial cells density: 10E04 cells/mL
- Control end cells density: 2.10E06 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3

GROWTH MEDIUM
- Standard medium used: yes

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Photoperiod: 16 h light; 8 h dark
- Stirring: 150 rpm
- light intensity: 6000 to 7100 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: fluorescence measurement using a cytofluorimeter after 0, 24, 48, 72 h

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2.2
Range finding study
- Test concentrations: 0.1 to 100% of saturated solution
- Results used to determine the conditions for the definitive study: result of the preliminary study not given in the study report; results were used to determine the limit concentration used in the definitive test

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

4 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

22 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Remarks on result:

other: 95% CL: 7.3 - 51 mg/L

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 184.2 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

4 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

act. ingr.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

4.4 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

act. ingr.

Basis for effect:

biomass

Remarks on result:

other: 95% CL: 0.53 - 10 mg/L

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

37 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

act. ingr.

Basis for effect:

biomass

Remarks on result:

other: 95% CL: 18-90 mg/L

Details on results:

- Observation of abnormalities: Some algae exposed to the 2 highest concentrations appeared turgid in comparison to the control.

Results with reference substance (positive control):

- Results with reference substance valid? yes
- EC50: 72 h EC50 biomass: 0.36 mg/L, growth rate: 0.9 mg/L (last test: 1997-10-24)

Reported statistics and error estimates:

Dunnett's test

concentration, nominal (mg/L)	biomass (%)	growth rate (%)
0	0.00	0.00
4.3	5.49	1.01
9.4	29.71	7.63
20.7	45.47	14.38
45.5	46.18	14.41
100	57.80	17.36
200	88.18	43.30

Validity criteria fulfilled:

yes

Conclusions:

In this study ETMA was found to inhibit the growth of the freshwater green alga Pseudokirchnerella subcapitata after 72 hours.
The NOEC, EC10 and EC50 values based on growth rate were 4.0 mg/L, 22.0 mg/L and >184.2 mg/L, respectively.
The NOEC, EC10 and EC50 values based on biomass were 4.0 mg/L, 4.4 mg/L and 37.0 mg/L, respectively. All effect levels are given based on initial measured concentrations of ETMA.

Executive summary:

In a 72 hour toxicity study, the cultures of Pseudokirchneriella subcapitata CCAP 27814 were exposed to ETMA at nominal concentrations of 0 (control), 4.3, 9.4 20.7, 45.5, 100 and 200 mg/L under static conditions in accordance with OECD Guideline 201, adopted 07 June 1984, and EU test method C.3, 04 April 1992.

Microscopic observation showed that some algae exposed to the 2 highest concentrations appeared turgid in comparison to the control.

The NOEC, EC10 and EC50 values based on growth rate were 4.0 mg/L, 22.0 mg/L and >184.2 mg/L, respectively. The NOEC, EC10 and EC50 values based on biomass were 4.0 mg/L, 4.4 mg/L and 37.0 mg/L, respectively. All effect levels are given based on initial measured concentrations of ETMA.

 

Results Synopsis

 

Test Organism: Pseudokirchnerella subcapitata CCAP 27814

Test Type: Static

 

72 hr ErC50: > 184.2 mg/L 

72 hr EyC50:  37 mg/L             95% C.I.: 18-90 mg/L

 

72 hr ErC10: 22 mg/L              95% C.I.:  7.3 - 51 mg/L

72 hr EyC10: 4.4 mg/L             95% C.I.: 0.53 - 10 mg/L

 

72 hr NOEC: 4.0 mg/L              

Endpoint(s) Effected:  growth rate, biomass

 

Description of key information

72 hr ErC50 > 184.2 mg/L; 72 hr ErC10=22 mg/L (95% C.I.:  7.3 - 51 mg/L); OECD guideline 201/EU method C.3, static; GLP

Key value for chemical safety assessment

EC50 for freshwater algae:

184.2 mg/L

EC10 or NOEC for freshwater algae:

22 mg/L

Additional information

One study in freshwater algae is available for ETMA, which is considered reliable without restriction (Klimisch score 1).

In a 72 hour toxicity study, the cultures of Pseudokirchneriella subcapitata CCAP 27814 were exposed to ETMA at nominal concentrations of 0 (control), 4.3, 9.4 20.7, 45.5, 100 and 200 mg/L under static conditions in accordance with OECD Guideline 201, adopted 07 June 1984, and EU test method C.3, 04 April 1992.

Microscopic observation showed that some algae exposed to the 2 highest concentrations appeared turgid in comparison to the control.

The NOEC, EC10 and EC50 values based on growth rate were 4.0 mg/L, 22.0 mg/L and >184.2 mg/L, respectively. The NOEC, EC10 and EC50 values based on biomass were 4.0 mg/L, 4.4 mg/L and 37.0 mg/L, respectively. All effect levels are given based on initial measured concentrations of ETMA.

According to OECD guideline 201 (adopted July 2011), the EC10 is preferred as relevant dose descriptor.