Oligomerisation products of 2,2'-[(1-methylethylidene)bis(4,1-phenyleneoxymethylene)]bisoxirane with acrylic acid and lauric acid

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

July 11, 2012 to august 9, 2012

Reliability:

1 (reliable without restriction)

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

other: ISO Standard 10634

Qualifier:

according to guideline

Guideline:

other: ISO DIS 9439 (Ultimate Aerobic Biodegradability - Method by Analysis of Released Carbon Dioxide)

Qualifier:

according to guideline

Guideline:

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

Qualifier:

according to guideline

Guideline:

other: OECD 301

Deviations:

no

GLP compliance:

yes

Vehicle:

no

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

-Source: The source of test organisms was activated sludge freshly obtained from a municipal
sewage treatment plant: 'Waterschap Aa en Maas', 's-Hertogenbosch, The Netherlands, receiving predominantly domestic sewage.
-Treatment: The freshly obtained sludge was kept under continuous aeration until further treatment. The concentration of suspended solids was 2.9 g/l in the concentrated sludge (information obtained from the municipal sewage treatment plant). Before use, the sludge was allowed to settle (50 minutes) and the supernatant liquid was used as inoculum at the amount of 10 ml/l of mineral medium.

Test type:

static

Water media type:

freshwater

Total exposure duration:

28 d

Test temperature:

22.1 and 22.7 °C

pH:

At t=0 d: 7.6
At t=28 d: 7.5 – 7.8

Details on test conditions:

- Test temperature: between 22.1 and 22.7°C.
- pH:
At t=0 d: 7.6
At t=28 d: 7.5 – 7.8
- pH adjusted: no
- Aeration of dilution water: Not before the test, the test is aerated continously
- Suspended solids concentration: The concentration of suspended solids was 2.9 g/l in the c
oncentrated sludge (information obtained from the municipal sewage treatment plant). Before use, the sludge was allowed to settle (50 minutes) and the liquid was decanted for use as inoculum at the amount of 10 ml/l of mineral medium.

- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 2 litre all-glass brown coloured bottles
- Number of culture flasks/concentration:
Test suspension: containing test substance and inoculum (2 bottles).
Inoculum blank: containing only inoculum (2 bottles)
Positive control: containing reference substance and inoculum (1 bottle).
Toxicity control: containing test substance, reference substance and inoculum (1 bottle).
- Method used to create aerobic conditions:
Synthetic air (a mixture of oxygen (ca. 20%) and nitrogen (ca. 80%)) was sparged through the s
olutions at a rate of approximately 1-2 bubbles per second (ca. 30-100 ml/min).


- Test performed in open system: yes
- Details of trap for CO2 and volatile organics if used:
CO2 was trapped in barium hydroxide solution. The amount of CO2 produced was determined by
titrating the remaining Ba(OH)2 with 0.05 M standardized HCl (1:20 dilution from 1 M HCl (Titrisol®ampul). Titrations were made on days 2, 5, 9, 14, 19, 23, 27 and 29 for the inoculum blank. For the positive and toxicity control, tritrations were made over a period of 14 days.

SAMPLING
- Sampling frequency: Titration were made on day: 2, 5, 9, 14, 19, 23, 27 and 29
- Sampling method: Titration of the whole volume of CO2-absorber

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Toxicity control: yes
- Other: Positive control containing reference substance and inoculum

Reference substance (positive control):

yes

Remarks:

sodium acetate

Key result

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

12 mg/L

Conc. based on:

test mat.

Basis for effect:

other: CO2 evolution

Remarks on result:

other: Based on DOC

Details on results:

In the toxicity control more than 25% biodegradation occurred within 14 days (36%, based on
ThCO2). Therefore, the test substance was assumed not to inhibit microbial activity.

Validity criteria fulfilled:

yes

Conclusions:

Under the study conditions RD04/201 was not readily biodegradable under modified Sturm test.

Executive summary:

A study was conducted to determine the ready biodegradability of the substance using the CO2 evolution test according to OECD Guideline 301B, EU Method C.4C and ISO DIS Method 9439, under GLP principles. A single test concentration of 12 mg/L (as total organic carbon, TOC) was tested for 28 days. The study consisted of two replicates of inoculum blanks, two replicates of the test bottles and a single bottle for the reference substance (sodium acetate) and a single bottle of the toxicity control. The test solutions were continuously stirred during the test, to ensure optimal contact between the test substance and the test organisms. The relative biodegradation values calculated from the measurements performed during the test period revealed no significant biodegradation of the test substance. In the toxicity control, the test substance was not found to inhibit microbial activity. The study met all acceptability criteria stated in the OECD guideline. Under the study conditions, the NOEC of the test substance to activated sludge microorganisms was determined to be 12 mg/L (Desmares-Koopmans MJE, 2012).

Description of key information

 

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

12 mg/L

Additional information

A study was conducted to determine the ready biodegradability of the substance using the CO2 evolution test according to OECD Guideline 301B, EU Method C.4C and ISO DIS Method 9439, under GLP principles. A single test concentration of 12 mg/L (as total organic carbon, TOC) was tested for 28 days. The study consisted of two replicates of inoculum blanks, two replicates of the test bottles and a single bottle for the reference substance (sodium acetate) and a single bottle of the toxicity control. The test solutions were continuously stirred during the test, to ensure optimal contact between the test substance and the test organisms. The relative biodegradation values calculated from the measurements performed during the test period revealed no significant biodegradation of the test substance. In the toxicity control, the test substance was not found to inhibit microbial activity. The study met all acceptability criteria stated in the OECD guideline. Under the study conditions, the NOEC of the test substance to activated sludge microorganisms was determined to be 12 mg/L (Desmares-Koopmans MJE, 2012).