Fluocortolone

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:

Aug 1991

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Draft report

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 100 mg/L
- Sampling method: direct sampling from vessel
- Sample storage conditions before analysis: direct analysis

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: 111.1 mg were dissolved in 1 mL triethylene glycol and stirred constantly for 40 minutes. 250 µL of this solution were dissolved in 250 mL tap water. This solution was filtered by a paper filter and filled into the test vessels. For the control 250 µL triethylene glycol were dissolved in 250 mL of tap water.
- Differential loading: Yes
- Controls: Yes, vehicle control
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): triethylene glycol
- Concentration of vehicle in test medium (stock solution and final test solution(s) or suspension(s) including control(s)): 1.02 mg/L

Test organisms (species):

Daphnia magna

Details on test organisms:

- Specification: Common name water flea
- Source: Schering AG, Experimental Toxicology, Berlin, Germany
- Age: 18 - 24 hours
- Holding: Parent animals were kept in glass vessels in water of the same quality and temperature as under experimental conditions
- Water: Normal tap water was used as dilution water, not polluted with harmful concentrations of chlorine, heavy metals or other substances, based on quarterly measurements and in accordance with the German standard "Trinkwasserverordnung" (Lund and Schiwy, 1986)

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test temperature:

20.8 - 21.2 °C

pH:

8.9 - 9.1

Dissolved oxygen:

9.0 - 9.1 mg/L

Nominal and measured concentrations:

The nominal test concentration of 100 mg/L corresponds to 92.1 mg/L of analytical result

Details on test conditions:

I. Exposure conditions:
- 20 Daphnia were used for the test concentration and also for the control group, randomly distributed into groups of five
- Labelled 100 mL test vessels holding 50 mL of the test solution or the dilution water (control group)
- Experimental design: The test was performed with 4 replicates of the test solution and the dilution water control with 5 Daphnia in each vessel
- Method of initiation: neonates were placed in prepared media
- Photoperiod: 12 h light : 12 h dark
- Aeration: none
- Feeding: None
- Test item concentration: 100 mg/L
- Medium renewal: none
- Criteria of effects: Immobilization and visual abnormalities

II Observations
- Immobilization and visual abnormalities were recorded at 24 and 48 hours

III. Hydrographical measurements:
- One additional vessel without Daphnia (measurement vessel) for each test and control solution, respectively, was used for the measurements of pH, temperature and oxygen content
- pH, oxygen concentration and temperature were measured at 0 and 48 hours

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

The EC50 was higher than the reached test concentration of 92.1 mg/L according to the analysis, with 99% confidence following binominal theory.

Validity criteria for the measurement of the daphnia toxicity:

Target condition according to guideline:	Actual condition according to the study:	Validity criteria met:
Young daphnids, aged less than 24 hours at the start of the test, are exposed to the test substance at a range of concentrations for a period of 48 h.	Age of daphnids used: 18 - 24 h Exposure time: 48 h	Yes
In the control, including the control containing the solubilising agent, not more than 10 % of the daphnids should have been immobilized. (Not more than 10 % of the control daphnids should show immobilisation or other signs of disease or stress, for example, discoloration or unusual behaviour such as trapping at surface of water)	The control mortalities are below the 10 % value which is regarded as the limit for natural mortality. As the physico-chemical measurements show, the composition of the test water corresponds to the nominal values. The EC50 of the reference substance lies within the required range. Thus, the study conditions correspond to the standard.	Yes
Test concentrations: At least five test concentrations should be used. They should be arranged in a geometric series with a separation factor preferably not exceeding 2.2. The highest concentration tested should  preferably result in 100 % immobilization, and the lowest concentration tested should preferably give no observable effect.	Test concentrations used: 1 (limit tests) Test concentration separation factor: None as limit test	Yes (with acceptable deviation)

 

Validity criteria fulfilled:

yes

Remarks:

for details please refer to "Any other information on results incl. tables"

Conclusions:

EC50 (48 h) >100 mg/L (nominal), >92.1 mg/L (measured)

Executive summary:

The study was conducted as a definitive test in agreement with the test guideline of the OECD, no. 202. Twenty Daphnia were used for the test concentration and also for the control group. The Daphnia were exposed to the test concentration of 100 mg/L (nominal) and the dilution water for a period of 48 hours under static conditions. lmmobilization was recorded at 24 hours and 48 hours. The test temperature was in the range of 20 °C ± 1 °C. The pH of the test concentration and the control group was 8.9 -9.1, the oxygen concentration was 9.0 -9.1 mg/L. The light dark rhythm was adjusted to 12 hours/12 hours. lmmobilized Daphnia were observed in the test concentration after 24 hours and 48 hours. Another observation was that all Daphnia in the test concentration showed apathetic swimming behaviour after 24 hours . For the concentration analysis samples were taken from each test vessel with the test product at 0 hours, 24 hours and 48 hours. After 48 hours of exposure the EC50 of fluocortolone to Daphnia magna was higher than 92.1 mg/L which was the test concentration according to the analysis. This toxicity study is classified as acceptable and satisfies the guideline requirements for the acute daphnia study.

Description of key information

EC50 (48 h) > 92.1 mg/L (measured)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

> 92.1 mg/L

Additional information

After 48 hours of exposure the EC50 was higher than the reached test concentration of 92.1 mg/L according to the analysis, with 99% confidence following binominal theory.