3,3-dimethylbutyne

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: Study according to internationally accepted guidelines but not GLP compliant

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method C.6 (Degradation: Chemical Oxygen Demand)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.5 (Degradation: Biochemical Oxygen Demand)

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: Guidence on the Application of the CLP Criteria

Deviations:

no

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

3,3-dimethylbutyne

EC Number:

213-035-3

EC Name:

3,3-dimethylbutyne

Cas Number:

917-92-0

Molecular formula:

C6H10

IUPAC Name:

3,3-dimethylbut-1-yne

Test material form:

gas under pressure: refrigerated liquefied gas

Details on test material:

Test item: 3,3-dimethylbutyne
CAS No. 917-92-0
Batch No. L37038N
Physical state Clear, transparent, liquid
Colour Colourless
Active ingredient content (GC) 97.5%
Storage 2-8°C in a tightly closed container

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

250 ml inoculum culture with 1 g/L dry substance was made by mixing 24 ml stock culture with 226 ml mineral medium.

Duration of test (contact time):

5 d

Initial test substance concentration

Initial conc.:

200 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

other: Pressure (The liberated carbon dioxide is absorbed by sodium hydroxide so the biological oxidation generates vacuum which is registered by the measuring heads.)

Details on study design:

This study was performed to evaluate the degradability of 3,3-dimethyl-1-butyne in an aerobic mixed bacterial culture on the base of quotient of biochemical oxygen demand (BOD) and chemical oxygen demand (COD). The degradability was calculated from the quotient of BOD5 and COD according to Guidance on the Application of the CLP Criteria.

For the tests a stock solution of test item was made by dissolving 0.296 ml (200 mg) test item in 1000 ml mineral medium. The nominal concentration of this stock solution was 200 mg/l.
The COD was determined by the standard dichromate method. Three replicates were measured in the test.
The BOD5 of test item was determined by OxiTop system. In this test the test solutions are inoculated with mixed aerobe bacterial culture and poured into 500 ml dark bottles. The vessels are placed into incubator at 20 +/- 2°C with continuos stirring. The test duartion was 5 days. N-Allylthiourea is added to each test vessel for inhibiting of nitrification.

Results and discussion

% Degradation

% Degradation 1

Parameter:

other: values of vacuum

Value:

1.4

Sampling time:

1 d

% Degradation 2

Parameter:

other: values of vacuum

Value:

1.7

Sampling time:

2 d

% Degradation 3

Parameter:

other: values of vacuum

Value:

1.5

Sampling time:

3 d

% Degradation 4

Parameter:

other: values of vacuum

Value:

1.2

Sampling time:

4 d

% Degradation 5

Parameter:

other: values of vacuum

Value:

1.4

Sampling time:

5 d

BOD5 / COD results

BOD5 / COD

BOD5 / COD 1

Parameter:

COD

Value:

1.592 g O2/g test mat.

BOD5 / COD 2

Parameter:

BOD5

Value:

0.023 g O2/g test mat.

BOD5 / COD 3

Parameter:

BOD5*100/COD

Value:

1.4 other: %

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

other: not rapidly degradable

Conclusions:

The BOD5/COD*100 ratio is less than 50%. In this Degredability Test for 3,3-dimethylbutyne the result indicated that the test item is not rapidly degradable in the aquatic environment.