Sodium hydroxyquinoline propanesulfonate

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:

Oct 2015 - Feb 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2016

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Sodium rac-1-hydroxy-3-(quinolin-6-yl)propanesulfonate

Cas Number:

1609934-65-7

Molecular formula:

C12H12NO4SNa

IUPAC Name:

Sodium rac-1-hydroxy-3-(quinolin-6-yl)propanesulfonate

Test material form:

solid: particulate/powder

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, predominantly domestic, adapted

Details on inoculum:

Source The source of test organisms was activated sludge freshly obtained from a municipal sewage treatment plant: 'Waterschap Aa en Maas', 's-Hertogenbosch, The Netherlands, receiving predominantly domestic sewage.
Treatment The freshly obtained sludge was kept under continuous aeration until further treatment. The concentration of suspended solids was determined to be 5 g/L in the concentrated sludge. 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):

> 1 - <= 29 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:

Test duration 28 days (last CO2 measurement on day 29). During the test period, the test media were aerated and stirred continuously.
Test vessels 2 litre glass brown coloured bottles.
Milli-RO water Tap-water purified by reverse osmosis (Milli-RO) and subsequently passed over activated carbon.
Stock solutions of mineral components A) 8.50 g KH2PO4
21.75 g K2HPO4
67.20 g Na2HPO4.12H2O
0.50 g NH4Cl dissolved in Milli-RO water and made up to 1 litre, pH 7.4 ± 0.2
B) 22.50 g MgSO4.7H2O dissolved in Milli-RO water and made up to 1 litre.
C) 36.40 g CaCl2.2H2O dissolved in Milli-RO water and made up to 1 litre.
D) 0.25 g FeCl3.6H2O dissolved in Milli-RO water and made up to 1 litre.
Mineral medium 1 litre mineral medium contains: 10 mL of solution (A),
1 mL of solutions (B) to (D) and Milli-RO water.
Barium hydroxide 0.0125 M Ba(OH)2 (Boom, Meppel, The Netherlands), stored in a sealed vessel to prevent absorption of CO2 from the air.
Synthetic air (CO2 < 1 ppm) A mixture of oxygen (ca. 20%) and nitrogen (ca. 80%) was passed through a bottle, containing 0.5 - 1 litre 0.0125 M Ba(OH)2 solution to trap CO2 which might be present in small amounts. The synthetic air was sparged through the scrubbing solutions at a rate of approximately 1-2 bubbles per second (ca. 30-100 mL/min).
Illumination The test media were excluded from light.

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 (2 bottles)
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

% Degradation

Key result

Parameter:

% degradation (CO2 evolution)

Value:

>= 5 - < 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 INC280-C1 (5% and 9%, based on ThCO2).
In the toxicity control, more than 25% biodegradation occurred within 14 days (37%, based on ThCO2). Therefore, the test item was assumed not to inhibit microbial activity.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

INC280-C1 was not readily biodegradable under the conditions of the modified Sturm test presently performed.