Sodium hydroxyquinoline propanesulfonate

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Oct 2015 - Mar 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:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test (Carbon and Ammonium Oxidation))

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition 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

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

After the 3-hour contact time the oxygen consumption was recorded for a period of approximately 10 minutes. During measurement, the sample was not aerated but continuously stirred on a magnetic stirrer.

Test solutions

Vehicle:

yes

Remarks:

Adjusted ISO medium

Details on test solutions:

Adjusted ISO medium, formulated using RO-water (tap-water purified by reverse osmosis; GEON Waterbehandeling, Berkel-Enschot, The Netherlands) with the following composition:
CaCl2.2H2O 211.5 mg/L
MgSO4.7H2O 88.8 mg/L
NaHCO3 46.7 mg/L
KCl 4.2 mg/L

Test organisms

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

The sludge was coarsely sieved (1 mm) and allowed to settle. The supernatant was removed and ISO-medium was added. A small amount of the sludge was weighed and dried overnight at ca. 105°C to determine the amount of suspended solids (3.0 g/L of sludge, as used for the test). The pH was 7.5 on the day of testing. The batch of sludge was used one day after collection; therefore 50 mL of synthetic medium (=sewage feed) was added per litre of activated sludge at the end of the collection day. The sludge was kept aerated at test temperature until use.

Study design

Test type:

not specified

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Test conditions

Test temperature:

20 ± 2°C

pH:

7.0 and 8.2

Details on test conditions:

The pH in all test vessels, before addition of sludge was between 7.6 and 7.7. After the 3 hour exposure period the pH was between 7.0 and 8.2.
The temperature continuously measured in the temperature control vessels ranged between 17.1 and 21.2°C during the test and was slightly outside the range prescribed by the study plan (20 ± 2°C)

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

>= 12 - <= 76 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Effect concentrations 2

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

>= 450 - <= 1 200 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Effect concentrations 3

Key result

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

<= 32 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Details on results:

The effects observed were in agreement with what was expected based on the results of the combined limit/range-finding test. The results of this test allowed for reliable determination of a NOEC and ECx values.
No statistically significant inhibition of the respiration rate of the sludge was recorded at or below a loading rate of 32 mg INC280-C1 per l. At higher concentrations the inhibitory effect of INC280-C1 on aerobic waste water (activated sludge) microorganisms increased with increasing concentration, ranging from 21% inhibition at 100 mg/L to 55% at 1000 mg/L.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of this present test INC280-C1 was not toxic to waste water bacteria (activated sludge) at or below a 32 mg/L (NOEC).
The EC10 was 40 mg/L (95% confidence interval: 12 – 76 mg/L).
The EC50 was 660 mg/L (95% confidence interval: 450 – 1200 mg/L).