6-sec-butylquinoline

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13th December 2018 to 25 February 2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

Version from 13th April 2004

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

Version from 30th May 2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

- Name: 6-sec-butylquinoline
- Purity by GLC: > 99.2%
- Lot number: 6SBQ5/2017
- Molecular formula: C13H15N
- Molecular weight: 185.26955 g/mol

Analytical monitoring:

yes

Details on sampling:

Samples were diluted with an equal amount of acetonitrile (dilution factor 2). A second dilution step was done for the sample with higher concentrations (10 * LOQ) using acetonitrile / medium 50/50 (% v/v) in a ratio 1:1.

Vehicle:

no

Details on test solutions:

Date of performance: 08. – 10. January 2019
Treatments: 0.46 / 1 / 2.2 / 4.6 / 10 mg/L (The concentrations to be tested are based on the result of a non-GLP pre-test)

The saturated solution was prepared for the test. This was done by weighing the nominal load of 10.0 mg/L resp. 9.9 µL/L test item (based on a density 1.0105 ± 0.0011 g/cm3 de-termined in LAUS study 17112706G912), adding the corresponding amount of dilution water and stirring moderate for 23 hours 10 minutes.
The lower phase was used unfiltered as test solution. The lower treatments were prepared by dilution of this stock solution with dilution water.

Test organisms (species):

Daphnia magna

Details on test organisms:

SPECIFICATION
Species: Daphnia magna
Authority: STRAUS
Strain: Berlin
Sex: female
Age: between 0 and 24 hours
Origin: Umweltbundesamt Berlin
In-house breeding since: 27. September 2007
Selection of the test system was made following the proposal of the guidelines.

ANIMAL HUSBANDRY
Daphnia magna is bred in the LAUS GmbH throughout the year. The animals are kept for the use in toxicity tests. They multiply by parthenogenesis, thus being genetically identical. The keeping is performed similar to the method described in the OECD guideline, following SOP 115 002 01 (Zucht und Hälterung von Daphnia magna STRAUS“), version 12 from 02. Feb. 2015.
Vessels: preserving glasses, nominal volume 2 L
Medium: M4-Medium (recipe of ELENDT)
Food: green algae (Desmodesmus subspicatus)
Medium renewal: twice a week
Photo period: 16/8 hours, using neon tubes
Temperature: 20 +- 2 °C

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

250 mg CaCO3 per litre

Test temperature:

19.6 – 20.2 °C

pH:

7.6 to 7.8

Dissolved oxygen:

7.8 to 8.8

Salinity:

not measured

Nominal and measured concentrations:

At the beginning and at the end of the test, the content of the test item in the test solutions was determined using HPLC-UV-determination. The concentrations determined at the start of the test were between 86% and 94% of the nominal concentration. At the end of the test the determined concentrations were between 73% and 77% of the nominal concentration.
Therefore, the determination of the results was based on the geometric mean of the measured concentrations. Geometric mean is calculated by multiplication of the n partici-pating concentrations and taking the nth root.

Details on test conditions:

TEST SYSTEM
- Test vessel: glass flasks nominal volume 65 mL
- Type (delete if not applicable): closed
- Aeration: dilution water is aerated
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Culture medium different from test medium: M4-Medium (recipe of ELENDT)
- Intervals of water quality measurement: pH was measured at the beginning of the test and at the end for the control and all test concentrations. Dissolved oxygen was measured at the beginning and at the end of the test for the control and all test concentrations. Temperature was measured continuously in a temperature control vessel.

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16/8 hours, using neon tubes


EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Immobility (including mortality)

VEHICLE CONTROL PERFORMED: yes/no

RANGE-FINDING STUDY
- Test concentrations: 0.46 / 1 / 2.2 / 4.6 / 10 mg/L
- Results used to determine the conditions for the definitive study: Five concentrations showed toxicity between 15% and 100% immobilisation. None of the animals was immobilised in the blank control.

Reference substance (positive control):

yes

Key result

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

3.48 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

1.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

<= 0.39 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

<= 0.39 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Results with reference substance (positive control):

None of the animals was immobilised in the blank control.

Reported statistics and error estimates:

The estimation of the biological results was accomplished using the software ToxRat® Professional, version 3.2.1.

Validity criteria fulfilled:

yes

Conclusions:

The 48h-EC50 was 1.80 mg/l based on nominal concentrations (95% confidence interval between 1.30 and 2.47 mg/l), remaining stable during the exposure period.

Executive summary:

One valid experiment was performed.

The study was performed using 5 concentrations ranging from 0.46 to 10 mg/L. For each test concentration and the blank control, 20 Daphnia were exposed to the test item for 48 hours in a static test system. After 24 and 48 hours, the immobilised Daphnia were counted.

Five concentrations showed toxicity between 15% and 100% immobilisation. None of the animals was immobilised in the blank control.

Potassium dichromate K₂Cr₂O₇(CAS No. 7778-50-9) was used as positive controlin a current reference study to assure that the test conditions are reliable.

 

At the beginning and at the end of the test, the content of the test item in the test solutions was determined using HPLC-UV-determination. The concentrations determined at the start of the test were between 86% and 94% of the nominal concentration. At the end of the test the determined concentrations were between 73% and 77% of the nominal concentration. Therefore, the determination of the results was based on the geometric mean of the measured concentrations.

The following results were determined for the test item 6-sec-butylquinoline (species: Daphnia magna). 

48h-NOEC= < 0.39 mg/L
48h-LOEC =≤0.39 mg/L
24h-EC₅₀= 3.48 mg/L
48h-EC₅₀= 1.80 mg/L

Description of key information

The 48h-EC50 was 1.80 mg/l based on nominal concentrations (95% confidence interval between 1.30 and 2.47 mg/l), remaining stable during the exposure period.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

1.8 mg/L