4-(3-phenylpropyl)pyridine

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

toxicity to microorganisms, other

Remarks:

Study was a toxicity control conducted as part of a CO2 evolution test in accordance with OECD Guideline 301B.

Type of information:

experimental study

Adequacy of study:

key study

Study period:

05 December to 03 January 2018

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

other:

Version / remarks:

Toxicity test performed as part of a ready biodegradability CO2 evolution test performed according to OECD 301B and EU C.4-C.

Deviations:

yes

Remarks:

On Days 18 and 20 of the test, the temperature was recorded as being 25.3 °C and 24.8 ºC respectively; a deviation from the Study Plan that tests maintain temperature of 22 ± 2ºC, did not affect validity.

Principles of method if other than guideline:

Toxicity test performed as part of a ready biodegradability CO2 evolution test performed according to OECD 301B and EU C.4-C.

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

The test substance is listed as 4-PPP. The test substance is a clear amber colored liquid. The test substance, purity of 98.5%, was obtained from the Sponsor, Vertellus Holdings LLC and stored at room temperature in the dark.

Analytical monitoring:

yes

Vehicle:

no

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

A mixed population of activated sewage sludge micro-organisms was obtained on 4 December 2017 from the aeration stage of the Severn Trent Water Plc sewage treatment plant at Loughborough, Leicestershire, UK, which treats predominantly domestic sewage.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

28 d

Nominal and measured concentrations:

A toxicity control containing the test item and sodium benzoate was prepared to assess any toxic effect of the test item on the sewage sludge micro-organisms used in the test. An amount of test item (35.1 mg) was dispersed in approximately 400 mL of mineral medium with the aid of high shear mixing prior to dispersal in inoculated mineral medium. An aliquot (51.4 mL) of the sodium benzoate stock solution was added to the test vessel and the volume was adjusted to 3 liters to give a final concentration of 11.7 mg test item/L plus 17.1 mg sodium benzoate/L, equivalent to a total of 20 mg carbon/L.

Key result

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

11.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other:

Remarks:

inhibition of CO2 evolution

Details on results:

At a test substance concentration of 11.7 mg/L and a reference substance concentration of 17.1 mg sodium benzoate/L, the toxicity control attained 54% degradation after 14 days and 81% degradation after 28 days, thereby confirming that the test substance did not exhibit an inhibitory effect on the sewage treatment micro-organisms used in the test (i.e., test substance and reference substance attained ≥ 25% degradation by Day 14 for the test substance to be considered as non-inhibitory).

Validity criteria fulfilled:

yes

Remarks:

IC 5% (protocol ≤ 5%); CO2 emitted by controls 30.38 mg/L (protocol <70 mg/L; difference replicates < 20% (protocol ≤20 %); degradation positive control 111% at 14 d (protocol ≤14 d), degradation toxicity d 14, 54% (protocol > 25%).

Conclusions:

The test substance is considered as not toxic towards the inoculum at a concentration of 11.7 mg/L. Degradation in the toxicity flask was 54% at 14 days. The guideline indicates that the test item can be considered as toxic towards the inoculum if degradation in the toxicity flask is below 25% at 14 days.

Description of key information

The key study was a toxicity control conducted as part of a CO₂ evolution test in accordance with OECD Guideline 301B. The test substance was shown to be non-inhibitory toward the inoculum at a concentration of 11.7 mg/L. Degradation in the toxicity flask was 54% at 14 days.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

11.7 mg/L