Fatty acids, C16-18 (even numbered), reaction products with tetraethylenepentamine, acetates (salts)

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:

February 07, 2005 - March 10, 2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

(1992)

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

(1992)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

- Name of test material: Fatty acids, C16-18, reaction products with tetraethylenepentamine, acetates (salts)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): ARA Ergolz ll, Fillinsdorf, Switzerland
The sludge was washed twice with tap water by centrifugation and the supernatant liquid phase was decanted. A homogenized aliquot of the final sludge suspension was weighed, thereafter dried and the ratio of wet to dry weight was calculated.
Based on this ratio, calculated amounts of wet sludge were suspended in test water to obtain a concentration equivalent to 4 g (±10%) dry material per liter. During holding, the sludge was aerated at room temperature until use. Prior to use, the sludge was
diluted with test water to a concentration of 1 g per liter (dry weight basis). Defined volumes of this diluted activated sludge were added to test water to obtain a final concentration of 30 mg dry material per liter.

Duration of test (contact time):

28 d

Initial conc.:

27 mg/L

Based on:

act. ingr.

Initial conc.:

17.2 mg/L

Based on:

other: TOC/L

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: test water was prepared according to the testing guidelines.

TEST SYSTEM
- Culturing apparatus: 5-liter flasks (amber glass)
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: Air was led through a bottle containing about 750 mL of a 2 M NaOH solution to trap CO2. The COz-free air was passed through the test solutions at a rate corresponding to about 30-100 mL/min.
- Details of trap for CO2 and volatile organics if used: Two absorber flasks, the first one containing 300 mL of 0.05 M NaOH and the second one containing 200 mL of 0.05 M NaOH, were connecied in series to the exit air line of each test flask.

SAMPLING
For the analysis of the COz-content, samples were taken on Day 2, 5, 7, 9, 12, 14, 19, 23, 27, 28 and 29.
On each sampling day, an aliquot of 5.0 mL was withdrawn from the absorber flask nearest to the test flask for analysis of inorganic carbon (IC). Additional samples for analysis of IC were withdrawn from the second absorber flask at the end of the exposure period on Day 28 in order to correct any carry over of CO2.
After sampling on Day 28, pH was measured in each test flask. Next, 1 mL of concentrated HCI was added to each test flask and the flasks were aerated overnight to drive off any residual CO. present. On Day 29, a sample from each absorber flask was withdrawn and analyzed for IC to determine residual CO, which was present in the test suspensions on Day 28. In this way, any residual CO. remaining in the test suspensions was determined as the difference between the amount of IC found before and after acidification.

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2 flasks
- Abiotic sterile control: 1 flask
- Toxicity control: 1 flask; 27.1 mg/L test item + 25.7 mg/l reference item

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (CO2 evolution)

Value:

9

Sampling time:

28 d

Remarks on result:

other: test item

Parameter:

% degradation (CO2 evolution)

Value:

35

Sampling time:

14 d

Remarks on result:

other: toxicity control

Details on results:

Test item:
At the end of the 28-day exposure period, the mean extent of biodegradation of the test item was 9%.

Abiotic control:
No degradation of the test item occurred in the abiotic control under the test conditions.

Toxicity control:
The extent of biodegradation in the toxicity control showed a similar course over the 28-day exposure period when compared to the procedure control containing the reference item, only. Within 14 days of exposure, the extent of biodegradation was 35%. Thus, according to the test guidelines, the test item had no inhibitory effect on activated sludge microorganisms at the tested concentration of 27.1 mg/L, as the biodegradation in the toxicity control was higher than 25% within 14 days of incubation.

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

Under the described conditions, no biodegradation was observed for C1618FA-TEPA-compound.
The test item had no inhibitory effect on activated sludge microorganisms at the tested concentration of 27.1 mg/L.

Executive summary:

The ready biodegradation of C16 18FA-TEPA-compound (ca. 90% a.i.) was investigated in a study according to EU Method C.4-C (1992) and OECD guideline 301 B (1992), CO2 evolution test over a period of 28 days and using an inoculum obtained from activated sludge from a predominantly domestic sewage treatment plant. The biodegradation rate was determined by measurement of carbon dioxide evolution.

Inoculum blank, procedural/functional control with the reference substance Sodium benzoate and a toxicity control with 27.1 mg/L test item and 25.7 mg/L reference item Sodium benzoate were performed.

The reference item degraded normally (63% by within 14 days). By the end of the test, the reference item was degraded to an average of 72%.

At the end of the 28-day exposure period, the mean extent of biodegradation of the test item was 9%. No significant biodegradation of C1618FA-TEPA-compound occurred under the test conditions within 28 days and the pass level for ready biodegradability of at least 60% degradation 10-day window within the 28-day period of the test was not reached.

The extent of biodegradation in the toxicity control showed a similar course over the 28-day exposure period when compared to the procedure control containing the reference item, only. Within 14 days of exposure, the extent of biodegradation was 35%. Thus, according to the test guidelines, the test item had no inhibitory effect on activated sludge microorganisms at the tested concentration of 27 mg/L, as the biodegradation in the toxicity control was higher than 25% within 14 days of incubation.

Description of key information

Under the described conditions, no biodegradation was observed for C1618FA-TEPA-compound. The test item had no inhibitory effect on activated sludge microorganisms at the tested concentration of 27.1 mg/L (EU Method C.4-C/OECD guideline 301 B, CO2 evolution test).

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater

Additional information

The ready biodegradation of C1618FA-TEPA-compound (ca. 90% a.i.) was investigated in a study according to EU Method C.4-C (1992) and OECD guideline 301 B (1992), CO2 evolution test over a period of 28 days and using an inoculum obtained from activated sludge from a predominantly domestic sewage treatment plant. The biodegradation rate was determined by measurement of carbon dioxide evolution.

Inoculum blank, procedural/functional control with the reference substance Sodium benzoate and a toxicity control with 27.1 mg/L test item and 25.7 mg/L reference item Sodium benzoate were performed.

The reference item degraded normally (63% by within 14 days). By the end of the test, the reference item was degraded to an average of 72%.

At the end of the 28-day exposure period, the mean extent of biodegradation of the test item was 9%. No significant biodegradation of C1618FA-TEPA-compound occurred under the test conditions within 28 days and the pass level for ready biodegradability of at least 60% degradation 10-day window within the 28-day period of the test wasnot reached.

The extent of biodegradation in the toxicity control showed a similar course over the 28-day exposure period when compared to the procedure control containing the reference item, only. Within 14 days of exposure, the extent of biodegradation was 35%. Thus, according to the test guidelines, the test item had no inhibitory effect on activated sludge microorganisms at the tested concentration of 27 mg/L, as the biodegradation in the toxicity control was higher than 25% within 14 days of incubation.

 

Also the closely related read-across substance was not readily biodegradable (the data have only been taken into the dossier in order to justify the read-across for ecotoxicity endpoints):

The ready biodegradation of the test item was investigated in a study conducted according to OECD Guideline 301F over a period of 28 days and using predominantly domesticactivated sludge micro-organismsas inoculum. The biodegradation rate was determined by measurement of O2 consumption. Inoculum blank, procedural/functional control with the reference substance sodium benzoate, and toxicity control using x100 mg/L test item and 100 mg/L reference compound were performed. This study is regarded as reliable without restriction and satisfies the guideline requirements for ready biodegradation. The test item proved to be not readily biodegradable. The functional control reached the pass level >60% after 14 d. In the toxicity control containing both test and reference item >25% biodegradation ThCOD occurred within 14 d thus indicating that the test item was not inhibitory to the activated sludge organisms at the concentration tested. Biodegradation after 28 days was 0%.