Farnesol

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:

07 July 2015 - 09 July 2015

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:

2004

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: All treatment levels and the control
- Sampling method: At the start of the exposure intervals (0 and 24 hours), sampling was carried out after preparation of the test concentrations. At the end of the exposure intervals (24 and 48 hours), samples were taken from additional replicates with test media, but without daphnids, which were incubated under test conditions until sampling, and analysed.
- Sample storage conditions before analysis: All samples were stored at 6 ± 2°C until sample preparation and at room temperature until the start of the analysis.

Vehicle:

no

Details on test solutions:

.PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A saturated solution with a nominal loading of 1000 mg/L of the test item was prepared with dilution water five days before the start of the exposure phase. Gentle stirring (to avoid formation of an emulsion) was carried out for 5 days with a magnetic stirrer at room temperature. After a separation of the phases after 1 hour of standing, the saturated solution was taken from the homogeneous phase (the approximate centre of the flask), checked for a Tyndall effect with a laser pointer and used as highest loading level and as stock solution for preparation of further loading levels by diluting with dilution water. After preparation of the saturated solution for the first exposure interval, the rest of the test item dispersion was stirred for further 24 hours as described above. On the following day, the saturated solution was taken from the homogeneous phase (the approximate centre of the flask), checked for a Tyndall effect and used as stock solution for preparation of further loading levels by diluting with dilution water.
- Controls: Dilution water
- Evidence of undissolved material: The tested solutions were visually clear throughout the exposure period.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Strain/clone: Daphnia magna STRAUS (Clone 5)
- Age of parental stock: 2 to 24 hours old daphnids from a healthy stock were used at the start of the study; no first brood progeny was used for the tes
- Feeding during test: None

CULTURE CONDITIONS
- Culture conditions: Elendt M4 modified to a total hardness of 160 to 180 mg CaCO2/L, 20 ± 2°C, 16 h light photoperiod
- Type and amount of food: Mix of unicellular green algae, e.g. Pseudokirchneriella subcapitata and Desmodesmus subspicatus, with an algae cell density of >106 cells/mL
- Feeding frequency: At least 5 times per week, ad libitum

ACCLIMATION
- Acclimation period: At least 2 hours in dilution water

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

267-269 mg CaCO3/L

Test temperature:

19-20 °C

pH:

7.73-8.10

Dissolved oxygen:

8.76-9.67 mg/L

Conductivity:

653-672 µS/cm

Nominal and measured concentrations:

Nominal concentrations: 6.25, 12.5, 25.0, 50.0 and 100 % of the saturated solution.
Geometric mean measured concentrations: 0.247, 0.532, 1.11, 2.36 and 5.52 mg/L.

Details on test conditions:

TEST SYSTEM
- Test vessel: 50 mL glass beakers (4 cm inner diameter, 7 cm height), loosely covered with watch glasses
- Type: Open
- Material, size, headspace, fill volume: 20 mL test volume
- Aeration: None reported
- Renewal rate of test solution: 24 hr renewal
- No. of organisms per vessel: 5
- No. of vessels per concentration: 4
- No. of vessels per control: 4

TEST MEDIUM / WATER PARAMETERS
- Culture medium different from test medium: Yes, ISO test water for test
- Intervals of water quality measurement: At the start of exposure (0 hr), at water renewal (24 hr, new and old solutions) and at the end of exposure (48 hr)

OTHER TEST CONDITIONS
- Adjustment of pH: None reported
- Photoperiod: 16/8 hours light/dark cycle
- Light intensity: Diffuse light, maximum 1340 lux

EFFECT PARAMETERS MEASURED: Immobilisation was determined in all groups after 24 and 48 hours

RANGE-FINDING STUDY
- Test concentrations: 10.0, 100 and 1000 mg/L
- Results used to determine the conditions for the definitive study: No immobilised daphnids observed at any test item concentration after 48 hours

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.532 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.568 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

1.11 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Mortality of control: None during test
- Other adverse effects control: No daphnids were immobilized or showed any signs of disease or stress (e.g. discoloration or unusual behaviour such as trapping on the surface of the water)
- Any observations that might cause a difference between measured and nominal values: The tested solutions were visually clear throughout the exposure period

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- Relevant effect levels: EC50 = 1.88 mg/L
- Limit test: No

Reported statistics and error estimates:

The NOEC and LOEC (after 48 hours) were estimated directly from the observation data, without mathematical calculation. The EC10 and the EC50 values after 24 and 48 hours were calculated by sigmoidal dose-response regression. The respective 95% confidence limits were calculated from the standard error and the t-distribution

Validity criteria fulfilled:

yes

Remarks:

In the control group, no daphnids were immobilized or showed any signs of disease or stress. The dissolved O2 concentration at the end of the exposure intervals was ≥ 8.76 mg/L

Conclusions:

The EC10, EC50 and EC100 were determined to be 0.532, 0.568 and 1.11 mg/L respectively for Daphnia magna after 48 hours.

Executive summary:

Acute toxicity to Daphnia magna was determined in a 48 -hour semi-static test. Daphnids were exposed to the test item at geometric mean measured concentrations of 0.247, 0.532, 1.11, 2.36 and 5.52 mg/L, alongside a dilution water control. The 48 -hour EC10, EC50 and EC100 were determined to be 0.532, 0.568 and 1.11 mg/L, respectively. The study was GLP-compliant and was conducted according to OECD guideline 202, therefore it is considered to be reliable without restriction (Klimisch 1).

Description of key information

The 48-hour EC50 for Daphnia magna was determined to be 0.568 mg/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.568 mg/L

Additional information

The short-term toxicity to Daphnia magna was determined in a 48 hour test according to OECD guideline 202 and conducted in compliance with GLP (2015). Organisms were exposed to measured concentrations (geometric mean) of 0.247, 0.532, 1.11, 2.36 and 5.52 mg/L. The EC10, EC50 and EC100 based on mobility were determined to be 0.532, 0.568 and 1.11 mg/L, respectively. This study is considered reliable and relevant (Klimisch 1) and is suitable for use as a key study.