2-Amino-3-bromopyridine

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

June 2016 - Feb 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

3-bromopyridin-2-amine

EC Number:

629-620-5

Cas Number:

13534-99-1

Molecular formula:

C5 H5 Br N2

IUPAC Name:

3-bromopyridin-2-amine

Test material form:

solid

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, predominantly industrial, non-adapted

Details on inoculum:

The source of test organisms was activated sludge freshly obtained from a municipal sewage treatment plant.
The freshly obtained sludge was preconditioned to experimental conditions by continuous aeration until further treatment. The concentration of suspended solids was determined to be 3.7 g/L in the concentrated. Before use, the sludge was allowed to settle (49 minutes) and the
supernatant liquid was used as inoculum at the amount of 10 mL/L of mineral medium.

Duration of test (contact time):

>= 0 - <= 28 d

Initial test substance concentration

Initial conc.:

12 mg/L

Based on:

TOC

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

Pre-incubation medium The day before the start of the test (day -1) mineral components, Milli-RO water (ca. 80% of final volume) and
inoculum (1% of final volume) were added to each bottle.
This mixture was aerated with synthetic air overnight to purge the system of CO2.
Type and number of bottles Test suspension: containing test item and inoculum (2 bottles).
Inoculum blank: containing only inoculum (4 bottles total;
2 bottles as blanks for the positive control aeration line and
2 bottles as blanks for the test item aeration line)
Positive control: containing reference item and inoculum (1 bottle).
Toxicity control: containing test item, reference item and inoculum (1 bottle).
Preparation At the start of the test (day 0), test and reference item were added to the bottles containing the microbial organisms and mineral components.
The volumes of suspensions were made up to 2 litres with Milli-RO water, resulting in the mineral medium described before.
Three CO2-absorbers (bottles filled with 100 mL 0.0125 M Ba(OH)2) were connected in series to the exit air line of each test bottle.

Results and discussion

Test performance:

Titrations were made every second or third day during the first 10 days, and thereafter at least every fifth day until day 28, for the inoculum blank and test suspension.
Titrations for the positive and toxicity control were made over a period of 14 days.
Each time the CO2-absorber nearest to the test bottle was removed for titration; each of the remaining two absorbers was moved one position in the direction of the test bottle. A new CO2-absorber was placed at the far end of the series.
Phenolphthalein (1% solution in ethanol, Merck) was used as pH-indicator.
On day 28, the pH of the test suspensions associated with the test item and toxicity control was measured. Thereafter, 1 mL of concentrated HCl (37%, Merck) was added to the bottles of the inoculum blank and test suspension. The bottles were aerated overnight to drive off CO2 present in the test suspension. The final titration was made on day 29.

% Degradation

% Degradation 1

Key result

Parameter:

% degradation (CO2 evolution)

Value:

2

Sampling time:

29 d

% Degradation 2

Key result

Parameter:

% degradation (CO2 evolution)

Value:

9

Sampling time:

29 d

Details on results:

The relative biodegradation values calculated from the measurements performed during the test period revealed no significant biodegradation of QAW039-C1 (2% and 9%, based on ThCO2).
In the toxicity control, more than 25% biodegradation occurred within 14 days (30%, based on ThCO2). Therefore, the test item was assumed not to inhibit microbial activity.
Functioning of the test system was checked by testing the reference item sodium acetate, which showed a normal biodegradation curve.

Any other information on results incl. tables

The temperature recorded in a vessel with water in the same room varied between 21.7 and

22.4°C.

The pH values of the different test media are 7.5 - 7.9

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

QAW039-C1 was not readily biodegradable under the conditions of the modified Sturm test presently performed.