2-methoxyethyl methacrylate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
This read-across is based on the hypothesis that source and target substances have similar toxicological properties because
• they are manufactured from similar or identical precursors under similar conditions
• they share structural similarities with common functional groups: methacrylate esters
• the metabolism pathway leads to comparable products (methacrylic acid and short chain alcohol).

Therefore, read-across from the existing (eco)toxicity studies on the source substances is considered as an appropriate adaptation to the standard information requirements of REACH regulation

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
see cross reference “Justification for read-across”

3. ANALOGUE APPROACH JUSTIFICATION
see cross reference “Justification for read-across”

4. DATA MATRIX
see cross reference “Justification for read-across”

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across: supporting information

Test organisms (species):

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

Test type:

static

Water media type:

freshwater

Total exposure duration:

72 h

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

Validity criteria fulfilled:

yes

Conclusions:

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.

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); 72 hr NOEC=4.0 mg/L; OECD guideline 201/EU method C.3, static; GLP; read-across from ETMA

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

No data on toxicity to freshwater algae are available for MTMA. A study in freshwater algae is available for ETMA, which is considered reliable without restriction (Klimisch score 1). A justification for read-across is given in the endpoint summary "Aquatic toxicity". 

 

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.

EC50 values of 0.367 mg/L for MTMA and 0.295 mg/L for ETMA were predicted using ECOSAR V1.11. Although the QSAR highly overestimates toxicity to algae, it is nevertheless used as supporting information. Since the QSAR results of both substances are in the same order of magnitude, the result obtained with the source substance ETMA can be used as surrogate date for the target substance MTMA.