Docosyl methacrylate

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

activated sludge respiration inhibition testing

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

weight of evidence

Justification for type of information:

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

Reason / purpose for cross-reference:

read-across source

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

> 10 000 mg/L

Reference 2

Endpoint:

activated sludge respiration inhibition testing

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

weight of evidence

Justification for type of information:

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

Reason / purpose for cross-reference:

read-across source

Details on test conditions:

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :

The physico-chemical oxygen uptake was determined by a test mixture containing the highest concentrations of test substance, synthetic sewage and distilled water but no activated sludge. The measured data of the test mixtures containing test substance and inoculum were corrected by this value.

TEST CONCENTRATIONS
As the solubility of 2.4 g test substance/l could not be obtained, the test material was added directly to the test mixtures.

Five concentrations of the test material (1, 10, 100, 1000, 10000 mg/l) were tested. As the solubility of the substance was far exceeded and no physical inhibitory effects (e.g. agglomeration of activated sludge) were observed, no further tests were performed.

Duration:

180 min

Dose descriptor:

EC50

Effect conc.:

> 10 g/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Reference 3

Endpoint:

toxicity to microorganisms

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

weight of evidence

Justification for type of information:

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

Reason / purpose for cross-reference:

read-across source

Duration:

16 h

Dose descriptor:

EC0

Effect conc.:

> 936 mg/L

Reference 4

Endpoint:

activated sludge respiration inhibition testing

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

weight of evidence

Justification for type of information:

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

Reason / purpose for cross-reference:

read-across source

Duration:

5 d

Dose descriptor:

EC0

Effect conc.:

> 500 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Reference 5

Endpoint:

activated sludge respiration inhibition testing

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

weight of evidence

Study period:

1989-07-18 to 1989-07-20

Justification for type of information:

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

Reason / purpose for cross-reference:

read-across source

GLP compliance:

yes

Key result

Duration:

180 min

Dose descriptor:

EC50

Effect conc.:

> 10 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Description of key information

The EC50 of the substance is determined to be > 10000 mg/L.

Key value for chemical safety assessment

EC50 for microorganisms:

10 000 mg/L

Additional information

Discussion

No experimental data on toxicity to microorganisms are available for the substance (CAS 16669-27-5) itself. Therefore, the ecotoxicological potential was assessed based on data available for the close structural analogues isotridecyl methacrylate (CAS 94247-059), octadecyl methacrylate (CAS 32360-05-7), methacrylic acid ester 13.6 (CAS 90552-04-8) and dodecyl methacrylate (CAS 142-90-5). Several tests with activated sludge are available, all of them valid without or with minor restrictions only. In accordance with Annex XI section 1.2 of Regulation (EC) No 1907/2006 (REACH), the information was evaluated in a weight of evidence approach.

In a static Activated Sludge Respiration Inhibition Test in compliance with GLP criteria and according to OECD Guideline 209, the close structural analogue isotridecyl methacrylate (CAS 94247-059) was tested over an duration of 180.0 min for toxicity to bacteria relevant for the biodegradation of the substance (Evonik Röhm GmbH, 1989). Mixed liquor from activated sludge of a predominantly domestic sewage treatment plant was obtained and aerated during transportation to the laboratory. Two samples of 10 ml were weighed and dried at 105 °C. The amount of solids was calculated and the wet sludge was suspended with isotonic solution to yield a concentration of 3 g suspended solids per litre. Subsequently, the activated sludge was amended with 50 ml synthetic sewage per litre and aerated at 20 °C + 2 °C overnight. Before use the amount of solids was determined and adjusted to 3 g/L. Aditionally, the pH-value was controlled. An adjustment was not necessary as the pH was in the accepted range of 6.0 – 8.0. The test concentrations were 1, 10, 100, 1000 and 10000 mg/L in nominal. As the solubility of the substance was far exceeded and no physical inhibitory effects (e.g. agglomeration of activated sludge) were observed, no further tests were performed. In addition, a positive control with the reference substance 3,5-Dichlorophenol was performed. In result, at concentrations up to 10000 mg/L, which are far exceeding the water solubility of the substance, no inhibition of the oxygen consumption of the bacteria was observed within 180 min. The EC50 (3 hours) of 3,5-dichlorophenol was in the accepted range of 5 to 30 mg/L. Therefore, it can be concluded that the test is valid and the close structural analogue is non-toxic to bacteria.

In a static Activated Sludge Respiration Inhibition Test according to EU Method C.11 and in compliance with GLP criteria, the close structural analogue octadecyl methacrylate (CAS 32360-05-7) was tested over an duration of 180.0 min (test temperature: 20 °C ± 2 °C; pH 6.0 - 8.0) for toxicity to bacteria relevant for the biodegradation of the substance (Evonik RohMax GmbH, UNTER 88-011, 1988). A sample of mixed liquor from a  predominantly domestic sewage plant was obtained. Five concentrations of the test material (1, 10, 100, 1000, 10000 mg/L) were tested. In addition, a positive control with the reference substance 3,5-Dichlorophenol was performed. As the solubility of octadecyl methacrylate was far exceeded and no physical inhibitory effects (e.g. agglomeration of activated sludge) were observed, no further tests were performed. In the first run of the experiment, the respiration rate after 180 min contact time could not be determined. the oxygen concentration in the measuring cell decreased rapidly. As consequence of technical reasons, the oxygen uptake after 30 min could not be determined in the second test run. In result, at concentrations up to 10000 mg/L, which are far exceeding the water solubility of the the structural analogue, no inhibition of the oxygen consumption of the bacteria was observed within 180 min. Therefore, it can be concluded that this close structural analogue is non-toxic to bacteria. The 3-hours EC50 of 3,5-dichlorophenol was in the accepted range of 5 to 30 mg/l. The test is regarded as valid.

In an Activated Sludge Respiration Inhibition Test in compliance with GLP criteria and according to OECD Guideline 209, the close structural analogue methacrylic acid methyl ester 13,6 (CAS 90552-04-8) was tested over an duration of 180.0 min for toxicity to bacteria relevant for the biodegradation of the substance (Evonik RohMax Additives GmbH, UNTER 88-012, 1988). The EC10 (3 h) for the inhibition of biodegradation was > 10000 mg/L. Therefore, it can be concluded that this close structural analogue is non-toxic to bacteria.

In a Growth Inhibition Test according to DEV L 8 ("Deutsches Einheitsverfahren", German standard method), Pseudomona gluorescens was exposed to the close structural analogue octadecyl methacrylate (CAS 32360-05-7). The principle of the test is that dissolved toxic substances inhibit the ability of the bacterium Pseudomonas gluorescens to produce organic acids from glucose. As a result, the EC0 (16 h) was > 936 mg/L. It can be concluded, that this close structural analogue is non-toxic to bacteria.

The toxicity to bacteria relevant for the biodegradation of the close structural analogue methacrylic acid methyl ester 13,6 (CAS 90552-04-8) was assessed in a static Activated Sludge Respiration Inhibition Test according to OECD Guideline 209 (Evonik Röhm GmbH, UNTER 88-032, 1989). Deviating from the guideline, the contact time was about 5 days (according to Offhaus). Due to low solubility, the close structural analogue was tested emulsified at concentrations of 100, 200 and 500 mg/L. In result, no inhibition of respirometric activity in any of the tested concentrations was observed. The 5-d EC0 (bacteria) was determined to be > 500 mg/L in emulsion according to OECD guideline 209.

Overall conclusion

The close structural analogues tested had an moiety chain length of C12–C22. No toxicity to bacteria was observed, the EC0 / EC50 values were, depending on the test conditions, between > 500 and > 10000 mg/L. Thus, concentrations of the test substances were several orders of magnitude above the limit of solubility. There is, however, no indication that the undissolved test substances interfered with bacterial respiration or the functioning of the test system. In conclusion, no inhibition of biodegradability in STPs or in the environment is expected.

Based on the most reliable information (Evonik Röhm GmbH, UNTER 89 -013, 1989), the EC 50 of docosyl methacrylate (CAS 16669 -27 -5) is considered to be > 10000 mg/L. This value is supported by two other studies (Evonik RohMax GmbH, UNTER 88-011, 1988; Evonik RohMax Additives GmbH, UNTER 88-012) since they had the same result (EC50 > 10000 mg/L). In two further studies (Evonik RohMax GmbH, UNTER 88-030, 1988; Evonik Röhm GmbH, UNTER 88-032, 1989) the estimated EC50 values were above the highest concentration tested.