2-[[(butylamino)carbonyl]oxy]ethyl acrylate

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:

14 Oct 2015 - 07 Jan 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Version / remarks:

17 Jul 1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

Version / remarks:

31 May 2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Swiss Federal Office of Public Health, Bern, Switzerland

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: ARA Werdhölzli, Zürich, Switzerland (04 Dec 2015)
- Storage conditions: The non-adapted activated sludge was aerated but not fed for 3 days.
- Storage length: 3 d
- Pretreatment: Prior to the test the sludge was washed twice with tap water and once with mineral medium. After centrifugation, the sludge, at a concentration twice the final concentration to be achieved for the test, was suspended in test medium.
- Concentration of sludge: 30 mg/L dry matter (in the final mixture)

Duration of test (contact time):

28 d

Initial conc.:

50 mg/L

Based on:

test mat.

Initial conc.:

100 mg/L

Based on:

ThOD

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: Aerobic mineral salts medium
- Test temperature: 22 ± 1 °C
- pH: 7.2 ± 0.2
- dry matter concentration: 30 mg/L in final mixture

TEST SYSTEM
- Culturing apparatus: 510 mL glass bottles, tighly closed with manometric BOD measuring devices.
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: Aeration of sludge prior to test
- Measuring equipment: OxiTop-C measuring head (WTW Wissenschaftlich-Technische Werkstätten GmbH & Co, Weilheim, Germany)
- Test performed in open system: No, the test bottles were tightly closed.
- Details of trap for CO2 and volatile organics if used: Butyl rubber quivers containing 2 pellets of sodium hydroxide each
- Other: The test vessels were stirred by an inductive stirring system.

SAMPLING
- Sampling frequency: O2 uptake was measured continuously with a manometric BOD measuring device.
- Sterility check if applicable: Yes (1 replicate), containing test item, ultra-pure water and 0.2 mM HgCl2 as sterilizing agent to prevent microbial decomposition.

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2 replicates, containing inoculum and test medium (no test item).
- Abiotic sterile control: 1 replicate, containing test item, ultra-pure water and 0.2 mM HgCl2 as sterilizing agent to prevent microbial decomposition.
- Toxicity control: 1 replicate, containing test medium, test item and reference item.
- Procedure control: 2 replicates, containing inoculum, test medium and reference item.

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

15

Sampling time:

28 d

Details on results:

The biodegradation of the test item was observed after a lag-phase of about 4 days . The biodegradation of the test item reached 12% at the end of the 10 d-window.

Results with reference substance:

The procedure control with sodium benzoate reached 76% degradation after 14 d, thus confirming the suitability of the inoculum and test conditions.

RESULTS ON ULTIMATE BIODEGRADATION (DOC)

The elimination based on dissolved organic carbon (DOC) analysis as compared to the applied total organic carbon (TOC) was calculated to be 41% for the test substance and 100% for the reference item (sodium benzoate), respectively. These results confirm the results of the limited biodegradability of the test substance based on O2 consumption.

TOXICITY CONTROL

At the applied initial test concentration of 51.0 mg/L the test item showed no significant toxic effect on the microbial population. More than 25% degradation occured within 14 d.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Description of key information

Not readily biodegradable (15% after 28 d, OECD 301 F)

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

There is one GLP study available, which investigated the ready biodegradability of the substance according to OECD guideline 301 F.

In a manometric respirometry test, a nominal concentration of 50 mg/L test item (corresponding to about 100 mg ThOD/L) was inoculated with 30 mg/L dry matter of microorganisms from activated sludge of a municipal sewage treatment plant in tightly closed glass bottles under static exposure conditions for 28 d. An inoculum blank, procedure, toxicity and abiotic sterile controls were run in parallel. Degradation was followed by the continuous measurement of O2 consumption. The amount of O2 taken up by the microbial population during biodegradation of the test item (corrected for the value in the blank control) was expressed as percentage of the theoretical O2 demand, ThOD, and serves as the measure for biodegradation. Additionally, ultimate biodegradation was determined based on dissolved organic carbon (mg DOC/L) concentrations at the end of the test compared to the respective concentrations of total organic carbon at the beginning (mg TOC/L) of the test.

Biodegradation of the test item was observed after a lag-phase of about 4 d. The biodegradation of the test substance reached 12% at the end of the 10 d- window and reached a final value of 15% after 28 d. Consequently, the pass level of 60% for ready biodegradability was not reached in the Manometric Respirometry Test, and the substance can therefore not be classified as readily biodegradable. The elimination based on DOC analysis as compared to the applied TOC was calculated to be 41% for test substance and 100% for the reference item, respectively. These results confirm the findings of the limited biodegradability of the test item based on O2 consumption. The procedure control reached 76% biodegradation after 14 d, thus confirming the suitability of the inoculum and test conditions. The abiotic sterile control confirmed that the test substance was not abiotically degraded by processes using O2 during the test (lack of oxygen consumption). The toxicity control showed no significant toxic effects on the microbial population since more than 25% degradation occurred within 14 d.