1-Octanol, reaction products with phosphorus oxide (P2O5), potassium salts

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

The experimental start date was 07 Jun 2018, and the experimental completion date was 17 Aug 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

2010

GLP compliance:

yes

Specific details on test material used for the study:

Purity: UVCB; solid matter 41.4%

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
The test item was added to Milli-RO water. Magnetic stirring for 15 minutes was applied to accelerate dissolution and to ensure homogeneity. Volumes of the stock solution corresponding to the test concentration were then added to the test media. Thereafter, 250 mL of activated sludge was added resulting in the required concentrations Optimal contact between the test item and test organisms was ensured by applying continuous aeration and stirring.

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Name and location of sewage treatment plant where inoculum was collected: Municipal sewage treatment plant: 'Waterschap Aa en Maas', 's -Hertogenbosch, Heeswijk-Dinther, The Netherlands, receiving predominantly domestic sewage
- Method of cultivation: The sludge was coarsely sieved and allowed to settle. The supernatant was removed and ISO-medium was added. 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.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Test temperature:

20.3 - 22.5°C

pH:

The pH in all test vessels, before addition of sludge, was between 7.4 and 7.7. After the 3 hour exposure period the pH was between 7.7 and 8.3.

Nominal and measured concentrations:

Nominal: 1000 mg solid matter/L

Details on test conditions:

TEST SYSTEM
- Test vessel: All glass open bottles/vessels
- Material, size, headspace, fill volume: Total volume 500 mL
- Aeration: continuously aerated and stirred on a magnetic stirrer
- No. of vessels per concentration: 5
- No. of vessels per control: 6
- No. of vessels per abiotic control: 1
- Sludge concentration: 3.0 g/L of sludge

OTHER TEST CONDITIONS
- Adjustment of pH: No

EFFECT PARAMETERS MEASURED
After the 3-hour contact time the oxygen consumption was recorded for a period of approximately 10 minutes:

TEST CONCENTRATIONS
Combined range-finding/limit test with a maximum concentration of 1000 mg solid matter/L

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Validity criteria fulfilled:

yes

Conclusions:

In conclusion, under the conditions of the present test the test item was not toxic to waste water bacteria (activated sludge) at or below a concentration of 100 mg solid matter/L (NOEC). The EC50 was above 1000 mg solid matter/L.

Executive summary:

The toxicity to microorganisms of the test item was assessed following OECD 209. During a combined range-finding/limit test study with un-adapted domestic sewage sludge, a study was performed with a maximum of 1000 mg solid matter/L. Under the conditions of the present test the test item was not toxic to waste water bacteria (activated sludge) at or below a concentration of 100 mg solid matter/L (NOEC). The EC50 was above 1000 mg solid matter/L.

Description of key information

The toxicity to microorganisms of the test item was assessed following OECD 209. During a combined range-finding/limit test study with un-adapted domestic sewage sludge, a study was performed with a maximum of 1000 mg solid matter/L. Under the conditions of the present test the test item was not toxic to waste water bacteria (activated sludge) at or below a concentration of 100 mg solid matter/L (NOEC). The EC50 was above 1000 mg solid matter/L.

Key value for chemical safety assessment

EC50 for microorganisms:

1 000 mg/L