Reaction mass of 1,1'-(2,2,4-trimethylhexane-1,6-diyl)bis-1H-pyrrole-2,5-dione and 1H-Pyrrole-2,5-dione, 1,1'-(2,4,4-trimethyl-1,6-hexanediyl)bis-

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Version / remarks:

adopted 14 July, 1992

Deviations:

yes

Remarks:

Concentration of suspended solids was 6.5 g/L (instead of 3-5 g/L). Therefore, 7.5 instead of 10 mL/L of the supernatant was used as inoculum. The deviation was considered to have no effect on the outcome of this study.

Qualifier:

according to guideline

Guideline:

EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)

Version / remarks:

December 1992

Deviations:

yes

Remarks:

Concentration of suspended solids was 6.5 g/L (instead of 3-5 g/L). Therefore, 7.5 instead of 10 mL/L of the supernatant was used as inoculum. The deviation was considered to have no effect on the outcome of this study.

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge: obtained from municipal sewage treatment plant Waterschap de Maaskant, 's-Hertogenbosch, The Netherlands.
- Storage conditions: kept under continuous aeration until further treatment
- Preparation of inoculum for exposure: sludge was allowed to settle (59 minutes) andthe liquid was decanted for use as inoculum at the amount of 7.5 mL/L of mineral medium

Duration of test (contact time):

28 d

Initial conc.:

19.5 mg/L

Based on:

test mat.

Initial conc.:

12 mg/L

Based on:

TOC

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium:
A) 8.50 g KH2PO4, 21.75 g K2HPO4, 67.20 g Na2HPO4*12H20, 0.50 g NH4CI, dissolved in Milli-Q water and made up to 1 litre, pH 7.4 ± 0.2
B) 22.50 g MgSO4* 7H2O dissolved in Milli-Q water and made up to 1 litre.
C) 36.40 g CaCI2*2H2O dissolved in Milli-Q water and made up to 1 litre.
D) 0.25 g FeCl3*6H2O dissolved in Milli-Q water and made up to 1 litre.
Mineral medium: 1 litre mineral medium contains: 10 ml of solution (A), 1 ml of solutions (B) to (D) and Milli-RO water.
(Tap-water purified by reverse osmosis (Milli-RO) and subsequently passed over activated carbon and ionexchange cartridges (Milli-Q) (Millipore Corp., Bedford, Mass., USA).
- Additional substrate: no
- Test temperature: 21.2 °C - 23.5 °C
- pH: 7.4 - 7.7
- pH adjusted: no
- Aeration of dilution water: Synthetic air (CO2 < 1 ppm): A mixture of oxygen (ca. 20%) and nitrogen (ca. 80%) was passed through a bottle, containing 0.5 - 1 L 0.0125 M
- Suspended solids concentration: 6.5 g/L suspended solids
- Continuous darkness: yes

TEST SYSTEM
- Number of culture flasks/concentration: 2
- Measuring equipment: 0.05 m standardised HCl
- Details of trap for CO2 and volatile organics if used: Ba(OH)2 solution

SAMPLING
- Sampling frequency: 2, 5, 7, 9, 14, 19, 23, 27 and 29 days
- Sampling method: CO2-absorber nearest to test bottle was removed for titration

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes, 2 bottles
- Toxicity control: yes, 1 bottle
- Positive control: yes, 1 bottle

Reference substance:

acetic acid, sodium salt

Parameter:

% degradation (CO2 evolution)

Value:

0

Sampling time:

2 d

Remarks on result:

other: mean of bottle A and bottle B

Parameter:

% degradation (CO2 evolution)

Value:

1

Sampling time:

5 d

Remarks on result:

other: mean of bottle A and bottle B

Parameter:

% degradation (CO2 evolution)

Value:

3

Sampling time:

14 d

Remarks on result:

other: mean of bottle A and bottle B

Parameter:

% degradation (CO2 evolution)

Value:

4

Sampling time:

23 d

Remarks on result:

other: mean of bottle A and bottle B

Parameter:

% degradation (CO2 evolution)

Value:

8

Sampling time:

29 d

Remarks on result:

other: mean of bottle A and bottle B

Details on results:

The percentage biodegradation in the toxicity control was > 25% (33% based on ThCO2) after 14 days. Therefore, the test substance was assumed not to inhibit microbial activity.

Results with reference substance:

The reference substance was degraded to 68% after 14 days.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

MATMD was not readily biodegradable under the conditions of the modified Sturm test.

Description of key information

The substance is not readily biodegradable (8% after 28 d, OECD 301B).

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater

Additional information

The ready biodegradabiltity of the substance was tested in a guideline study following OECD 301B. The substance was inoculated with activated sludge taken from a municipal sewage treatment plant. The degradation rate was determined by measuring the CO2 evolution during the test period of 28 days. At test termination a degradation rate of 8% was determined. Based on the test results the substance is not readily biodegradable according to OECD criteria.