Oligomerisation products of 2,2'-[(1-methylethylidene)bis(4,1-phenyleneoxymethylene)]bisoxirane with acrylic acid and fatty acids, C18-unsatd., dimers and nonanoic acid

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Cross-reference

Reason / purpose for cross-reference:

data waiving: supporting information

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From October 12, 2011 to November 10, 2011

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)

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Principles of method if other than guideline:

In addition, the procedures were designed to meet the test methods prescribed by the following guidelines:
- ISO Standard 9439 “Water Quality - Evaluation of ultimate aerobic biodegradability of organic compounds in aqueous medium - carbon dioxide evolution test (1999);
- ISO Standard 10634 "Water Quality - Guidance for the preparation and treatment of poorly water-soluble organic compounds for the subsequent evaluation of their biodegradability in an aqueous medium" (1995).

GLP compliance:

yes

Specific details on test material used for the study:

Ebecryl® 3702 radiation curing resin; Molecular weight: Mn is 950, Description: clear green to brown highly viscous liquid, Batch: HTIF11021, Purity: not indicated by the sponsor; treated as 100% pure, Test substance storage: at room temperature in the dark, Stability under storage conditions: stable, Solubility in water: no.

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Remarks:

freshly obtained from a municipal sewage treatment plant

Details on inoculum:

The freshly obtained sludge was kept under continuous aeration until further treatment. The concentration of suspended solids was 4.6 g/l in the concentrated sludge. Before use, the sludge was allowed to settle (35 minutes) and the supernatant liquid was used as inoculum at the amount of 10 ml/l of mineral medium.

Duration of test (contact time):

28 d

Initial conc.:

15.5 mg/L

Based on:

other: TOC/L

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

Definitions:
-Readily biodegradable are those test substances giving a result of at least 60% biodegradation within 28 days. This pass level must be reached within the 10 days immediately following the attainment of 10% biodegradation (10-day window).
-Theoretical carbon dioxide (ThCO2) is the quantity of carbon dioxide calculated (mg) to be produced from the known or measured carbon content of the test substance when fully mineralized; also expressed as mg carbon dioxide evolved per mg test substance.
-Total Organic Carbon (TOC) of a sample is the sum of the organic carbon in solution and in suspension.

Reference substance:

acetic acid, sodium salt

Test performance:

- Temperatures recorded: 20.1 - 21.5°C.
- pH on Day 28: 7.5 - 7.8.

Key result

Parameter:

% degradation (CO2 evolution)

Value:

0

Sampling time:

29 d

Remarks on result:

other:

Remarks:

not readily biodegradable

Details on results:

The ThCO2 of the test substance was calculated to be 2.81 mg CO2/mg.

(In the toxicity control more than 25% biodegradation occurred within 14 days (35%, based on ThCO2). Therefore, the test substance was assumed not to inhibit microbial activity).

Results with reference substance:

The ThCO2 of sodium acetate was calculated to be 1.07 mg CO2/mg.

Because the theoretical calculation of the CO2 production was not possible a sample of the test substance was taken for TOC analysis.

ThCO2, expressed as mg CO2/mg test substance, was calculated from the results of carbon analysis. The first step in calculating the amount of CO2 produced is to correct for background (endogenous) CO2 production. Thus the amount of CO2 produced by a test substance is determined by the difference (in ml of titrant) between the experimental and blank Ba(OH)2 traps. The amount of 0.05 N HCl titrated is converted into mg of CO2 produced:

mg CO2 = (0.05 x delta ml HCL titrated)/2 x 44 = 1.1 x dela ml HCL titrated

Relative biodegradation values were calculated from the cumulative CO2 production relative to the total expected CO2 production based on the total carbon content of the amount of test substance present in the test bottles. A figure of more than 10% biodegradation was considered significant. The relative biodegradation values were plotted versus time together with the relative biodegradation of the positive control. If applicable, the number of days is calculated from the attainment of 10% biodegradation until 60% biodegradation. Should this period be ≤ 10 days (10-day window), then the test substance is designated as readily biodegradable. Toxicity control: if less than 25% biodegradation (based on ThCO2) occurred within 14 days, the test substance was assumed to be inhibitory. The total CO2 evolution in the inoculum blank was determined by the cumulative difference (in ml of titrant) between the blank Ba(OH)2 traps and fresh Ba(OH)2.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

Under the study conditions (modified Sturm test), the test substance was considered not readily biodegradable.

Executive summary:

A study was conducted to evaluate the ready biodegradability of the tests substance according to OECD Guideline 301B (CO2 evolution test), EU Method C.4 - C and ISO standards 9439 and 10634. Because the theoretical calculation of CO2 production was not possible, a sample of the test substance was taken for total organic carbon (TOC) analysis. The TOC content was determined to be 77%. The substance was tested in duplicate at 15.5 mg/L, i.e. 12 mg TOC/L. Based on TOC, the corresponding ThCO2 was calculated to be 2.81 mg CO2/mg. Due to low solubility in water, weighed amounts of substance on a glass plate were added to 2 L test bottles containing medium with microorganisms and mineral components. The relative biodegradation values calculated over a 28 d period revealed no significant biodegradation. In the toxicity control, the substance did not inhibit microbial activity. Under the study conditions (modified Sturm test), the test substance was considered not readily biodegradable (Desmares-Koopmans, 2011).