Docosyl 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 based on grouping of substances (category approach)

Adequacy of study:

key study

Study period:

2005-03-01 to 2005-03-04

Justification for type of information:

For "read across justification" please refer to chapter 13.

Reason / purpose for cross-reference:

read-across source

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

10 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: biomass and growth rate

Remarks on result:

other: 95% confidence interval: not applicable

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

> 10 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: biomass and growth rate

Remarks on result:

other: 95% confidence interval: not applicable

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 10 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: biomass and growth rate

Remarks on result:

other: 95% confidence interval: not applicable

Description of key information

The 72-h EC50 and NOEC of the substance is determined to be > 10 µg/L and 10.0 µg/L, respectively.

Key value for chemical safety assessment

EC50 for freshwater algae:

10 µg/L

EC10 or NOEC for freshwater algae:

10 µg/L

Additional information

Discussion

No experimental data on toxicity to aquatic algae and cyanobacteria are available for the substance itself. Therefore, the ecotoxicological potential to algae is assessed based on data available for the close structural analogue dodecyl methacrylate (CAS 142-90-5).

The toxicity of dodecyl methacrylate (CAS 142-90-5) to the unicellular freshwater green alga Desmodesmus subspicatus was determined according to the principles of OECD-Guideline 201 (1984) and EC Commission Directive 92169l EC Method C.3 (Evonik RohMax Additives GmbH, UNTER03-008, 2005). The aim of the study was to assess the effects on growth rate and biomass production over a period of 72 h. The study was conducted under static conditions with an initial cell density of nominally l0E+4 cells/mL. A limit test with a nominal concentration of 10 µg/L was prepared. This concentration is higher than the solubility in water (< 1 µg/l), but has, nevertheless, been chosen with regard to the feasibility of attaining appropriate and analysable test concentrations at 10 µg/L. Three replicates were tested for the limit concentration and six replicates for the control. Microscopic evaluation of the cells at start and end of the incubation period revealed no morphological abnormalities. Environmental conditions, pH-value, measured at 0 and 72 h, and room temperature, measured continuously, were determined to be within the acceptable limits. Control analysis was carried out using HPLC at test start and at 24 h intervals. The recovery rate of the limit concentration was 105 % at test start and 94 % at test end. All effect values are based on the nominal test item concentration. Dodecyl methacrylate did not cause any inhibiting effects to Desmodesmus subspicatus after 72 h when tested at a concentration of 10 µg/L. NOEC and EC50 values based on growth inhibition and biomass production were > 10 µg/L, respectively. This toxicity study is classified as acceptable and satisfies the guideline requirements for Algae, Growth Inhibition study.

Overall conclusion

In conclusion, the structural analogue dodecyl methacrylate (CAS 142 -90 -5) did not cause any inhibiting effects to Desmodesmus subspicatus after 72 h when tested at a concentration of 10 µg/L. Based on this results, the 72 -h EC50 and NOEC of docosyl methacrylate (CAS 16669-27-5) is considered to be > 10.0 and 10.0, respectively.