2,2'-oxydi(ethylamine)

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:

2012-04-30 - 2012-06-20

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)

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

- Name of test material (as cited in study report): BAEE
-Chemical name: bis(aminoethyl)ether
- Physical state: liquid
- Analytical purity: 95.9%
- Lot/batch No.: LL080179
- Expiration date of the lot/batch: not supplied
- Storage condition of test material: at room temperature in the dark

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): activated sludge was sampled from the aeration stage of the Severn Trent Water Plc sewage treatment plant at Loughborough, Leicestershire, UK (treating predominantly domestic sewage, sample taken on 21 May 2012)
- Laboratory culture: sample first washed twice by settlement and resuspension in mineral medium to remove excess DOC, washed sample maintained under continuous aeration in the lab at 21°C until further use
- Concentration of sludge before inoculation: 2.8 g/L (filtration, drying, weighing)
- Initial cell/biomass concentration: 30 mg SS/L

Duration of test (contact time):

28 d

Initial conc.:

21.7 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

PRELIMINARY INVESTIGATIONAL WORK
- To investigate whether the test item adsorbed to filter matrices and/or to activated sludge.
- 100 mg test item dissolved in 1 L mineral medium. 2 samples for DOC analysis: one untreated and one filtered (0.45 µm Gelman AcroCap filter).
- Similar 100 mg/L solution inoculated at 30 mg SS/L. 2 samples for DOC analysis: one after filtration, and the other after centrifugation at 4000 g for 15 min. Control samples prepared in the same way from a similar solution without activated sludge.

TEST CONDITIONS
- Composition of medium: as recommended by OECD
- Additional substrate: none
- Solubilising agent (type and concentration if used): none
- Test temperature: 21°C
- pH: 7.5-7.8 throughout the study
- pH adjusted: yes, to 7.4 at the start of testing, using diluted HCl or NaOH solutions
- Suspended solids concentration: 30 mg SS/L
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 5-L test culture vessels containing 3 L of medium
- Number of culture flasks/concentration: 2
- Test vessels sealed and CO2-free air bubbled through solution at 30-100 mL/min/vessel and stirred continuously by magnetic stirrer
- Measuring equipment:
- Details of trap for CO2 and volatile organics if used: two 500-mL Dreschel bottles containing 350 mL 0.05 M NaOH (prepared using purified degassed water)
- On day 28, 1 mL of concentrated HCl was added to drive off any inorganic carbonates formed

SAMPLING
- Sampling frequency: first CO2 adsorber vessel sampled on day 0, 2, 6, 8, 10, 14, 21, 28 and 29; second adsorber vessel sampled on day 0 and 29
- For DOC, IC and TC analysis, samples (30 mL) taken on day 0 from test item vessels and inoculum control. All samples filtered (0.45 µm) before analysis.

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes (inoculum + mineral medium, 2 vessels)
- Abiotic sterile control: no
- Toxicity control: yes (inoculum + mineral medium + 21.7 mg/L test item + 17.1 mg/L sodium benzoate (together 20 mg C/L), 1 vessel)
- Procedure control: yes (inoculum + mineral medium + 17.1 mg/L sodium benzoate (10 mg C/L), 2 vessels)

STATISTICAL METHODS:
- Student's t-test to determine significant differences between test and control groups.

Reference substance:

benzoic acid, sodium salt

Preliminary study:

The test item was demonstrated not to adsorb to filter matrices or activated sludge. Therefore, samples taken for DOC analysis were filtered to remove SS present without loss of test item.

Test performance:

- Total CO2 evolution in inoculum control vessels on day 28 was 31.54 mg/L, satisfying the validity criterion (< 40 mg/L).
- IC content of test item suspension at start of test was < 5% of TC, satisfying the validity criterion.
- The difference between values for CO2 production at end of test for replicate vessels was < 20%, satisfying the validity criterion.
- Toxicity control attained 39% degradation after 14 days, confirming that the test item was not toxic to the activated sludge organisms (should be >= 25% after 14 days).
- Sodium benzoate attained 76% degradation after 14 days, confirming suitability of inoculum and test conditions (should be >= 60% after 14 days).

Key result

Parameter:

other: % ThCO2

Value:

0

Sampling time:

28 d

Remarks on result:

other: not readily biodegradable

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

In this CO2 evolution test conducted according to OECD guideline 301B, no biodegradation of the test substance was observed after 28 days using activated sludge from a treatment plant treating predominantly domestic sewage. Test performance was demonstrated to be good (as shown by the results with the reference item and the toxicity control) and all validity criteria were met. The results of the test can be considered reliable. The test substance is not readily biodegradable.

Description of key information

In a 28-day CO2 evolution test according to OECD guideline 301B and performed under GLP, no biodegradation of the test substance was observed (Roulstone, 2012).

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

One reliable (Klimisch 1) study is available (Roulstone, 2012) which is considered as key study to cover this endpoint. This study determined the ready biodegradability of BAEE in a 28-day CO2 evolution test conducted according to OECD guideline 301B, in the presence of activated sludge from a waste water treatment plant treating predominantly domestic sewage. Test performance was demonstrated to be good (as shown by the results with the reference item and the toxicity control) and all validity criteria were met. The results of the test can be considered reliable. No biodegradation of the test substance was observed after 28 days; the test substance is not readily biodegradable.