Zinc methacrylate

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

toxicity to microorganisms, other

Remarks:

Ready biodegradability study (OECD 301F)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

30 July - 10 October 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

other: OECD TG 301F

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Vehicle:

yes

Remarks:

Purified water

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Source of activated sludge: Wastewater treatment plant (ARA Ergolz II, Füllinsdorf, Switzerland) t
reating predominantly domestic wastewater
- Preconditioning: The sludge was washed twice with tap water by centrifugation and the supernatant
liquid phase was decanted. During the holding period of one day prior to use, the sludge was aerated
at room temperature.
- Dry weight of suspended solids: 4 g/L
- Concentration of sludge in test water: 30 mg dry material/L

Nominal and measured concentrations:

0 and 100 mg/L

Details on test conditions:

TEST CONDITIONS
- Composition of medium: Nutrient medium contained per litre of deionised water: 85 mg KH2PO4,
217.5 mg K2HPO4, 334 mg Na2HPO4.2H2O, 5 mg NH4Cl, 22.5 mg MgSO4.7H2O, 36.4 mg C
aCI2.2H2O, 0.25 mg FeCI3.6H2O
- Source/preparation of dilution water: Purified water
- Test temperature: 22 °C, maintained with a built-in thermostat and checked at least on each working
day.
- pH: 7.3-7.4 (at the start of the test); 7.5–8.4 (at the end of test)
- pH adjusted: Yes, pH was adjusted from 7.9 to 7.4 with a diluted hydrochloric acid solution.
- Continuous darkness: Yes
TEST SYSTEM
- Culturing apparatus: Flasks (500 mL)
- Number of culture flasks/concentration: Two for test item, inoculum and procedure control and one
for toxicity control
- Measuring equipment: SAPROMAT D12 (Voith GmbH, Heidenheim
- Details of trap for CO2: Evolved CO2 was absorbed by soda lime
SAMPLING
- Sampling frequency: Oxygen consumption was recorded manually by taking a daily reading at least
on each working day. The pH was measured in each test flask before the addition of the activated s
ludge inoculum and at the end of incubation.
CONTROL AND BLANK SYSTEM
- Inoculum blank: Yes; containing inoculum only
- Procedure control: Yes; containing reference substance (sodium benzoate) with inoculated medium
- Toxicity control: Yes; containing test material and reference substance (sodium benzoate) with
inoculated medium

Reference substance (positive control):

yes

Remarks:

benzoic acid, sodium salt 100 mg/L; purity: 99.7 %; source: Sigma-Aldrich

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Remarks:

no effects observed on microbial growth

Details on results:

Initial test material concentration: 100 mg/L
- Theoretical oxygen demand (ThOD) = 1.16 mg O2/mg
- % biodegradation on Day 4: > 10%
- % biodegradation on Days 5: > 60%
- % biodegradation on Days 28 = 92%

Results with reference substance (positive control):

Results with reference substance
- Theoretical oxygen demand (ThOD) = 1.67 mg O2/mg
- % biodegradation on Day 14 = 84%
- % biodegradation on Days 28 = 90%

Validity criteria fulfilled:

yes

Conclusions:

Under the test conditions, the NOEC for toxicity to microorganisms can be considered to be the tested concentration of 100 mg/L of Zinc Dimethacrylate

Executive summary:

In a ready biodegradation study performed according to OECD Guideline 301 F and GLP, Zinc Dimethacrylate (CAS 13189-00-9; EC: 236-144-8) was tested at a concentration of 100 mg/L and the inoculum was activated sewage sludge, domestic. The degradation of the test material was assessed by the determination of the oxygen consumption. The test treatments, inoculum blank and procedure control were measured in duplicates and one vessel was used for toxicity control. At 100 mg/L test concentration, greater than 10% degradation was reached by Day 4 and greater than 60% biodegradation was reached by Day 5. Hence, the test material met the 10-day window requirement for ready biodegradability. On Day 28, the biodegradation was 92%. The reference material (sodium benzoate) reached greater than 60% biodegradation within 3 days. The biodegradation in the toxicity control was 84% within 14 days and had no toxic effect on the micro-organisms. Hence, it met the validity criteria for reference material and toxicity control. Under the test conditions, the NOEC for toxicity to microorganisms can be considered to be the tested concentration of 100 mg/L of Zinc Dimethacrylate (Eisner, 2013).

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

100 mg/L

Additional information

In a ready biodegradation study performed according to OECD Guideline 301 F and GLP, Zinc Dimethacrylate (CAS 13189-00-9; EC: 236-144-8) was tested at a concentration of 100 mg/L and the inoculum was activated sewage sludge, domestic. The degradation of the test material was assessed by the determination of the oxygen consumption. The test treatments, inoculum blank and procedure control were measured in duplicates and one vessel was used for toxicity control. At 100 mg/L test concentration, greater than 10% degradation was reached by Day 4 and greater than 60% biodegradation was reached by Day 5. Hence, the test material met the 10-day window requirement for ready biodegradability. On Day 28, the biodegradation was 92%. The reference material (sodium benzoate) reached greater than 60% biodegradation within 3 days. The biodegradation in the toxicity control was 84% within 14 days and had no toxic effect on the micro-organisms. Hence, it met the validity criteria for reference material and toxicity control. Under the test conditions, the NOEC for toxicity to microorganisms can be considered to be the tested concentration of 100 mg/L of Zinc Dimethacrylate (Eisner, 2013).