diethylmethoxyborane

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP Guideline study with good documentation. The substance is unstable in the test medium, but no chemical analytical data are available. The identity of the residual fraction is therefore unclear.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1997

Report date:

1997

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

425-380-9

EC Name:

-

Cas Number:

7397-46-8

Molecular formula:

C5H13BO

IUPAC Name:

methyl diethylborinate

Details on test material:

- Name of test material (as cited in study report): DEMB
- Physical state: liquid
- Analytical purity: 99.4%
- Stability under test conditions: No, hydrolyses slowly
- Storage condition of test material: At room temperature in the dark

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, domestic (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge: secondary effluent freshly obtained from a municipal sewage treatment plant: 'Waterschap de Maaskant', 's-Hertogenbosch, the Netherlands.
- Preparation of inoculum for exposure: Secondary effluent was filtered through a coarse filter paper, the first 200 mL was discarded. The filtrate was kept aerated until inoculation.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

2 mg/L

Initial test substance concentration 2

Initial conc.:

5 mg/L

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: test substance and inoculum (100 µL flitrate of secondary effluent per litre of final volume) in mineral medium
- Test temperature: 21 °C
- pH: 7.3 - 7.6
- Aeration of dilution water: before initiation of the test
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 250-300 mL BOD bottles with glass stoppers
- Number of culture flasks/concentration: 2
- Measuring equipment: WTW: OXI 530 dissolved oxygen meter, TriOxmatic EO 200 oxygen electrode, electrolyte type ELY/N.

SAMPLING
- Sampling frequency: Immediately at the start of the experiment (day 0), and at day 7, 14, 21 and 28 in duplicate.

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Toxicity control: yes
- Other: positive control

Reference substance

Reference substance:

acetic acid, sodium salt

Results and discussion

% Degradation

% Degradation 1

Parameter:

% degradation (O2 consumption)

Value:

>= 31 - <= 41

Sampling time:

28 d

Remarks on result:

other: 2 mg/L

% Degradation 2

Parameter:

% degradation (O2 consumption)

Value:

>= 29 - <= 39

Sampling time:

28 d

Remarks on result:

other: 5 mg/L

Details on results:

- The toxicity control revealed that the substance did not inhibit microbial activity.

- Degradation kinetics:
Day 7: 38 %
Day 14: 38 %
Day 21: 41 %
Day 28: 31 %

BOD5 / COD results

Results with reference substance:

The oxygen depletion in the toxicity control was always more than 75% of the sum of the oxygen depletion of the positive control and the test
substance (2 mg/L). Therefore, DEMB was assumed to be not inhibitory.

Applicant's summary and conclusion

Interpretation of results:

other: moderately/partially biodegradable