4,6-Dichloro-5-fluoropyrimidine

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:

27 Mar - 06 Apr 2002

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 0.06, 0.13, 0.25, 0.5 and 1 mg/L
- Sampling method: Sampling schedule of chemical analysis 0 and 48 h

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A stock solution was prepared to give series of test concentrations. To achieve this 2.4 mg of the test substance were added to 2 litres of dilution water, treated with an ultra turrax for 60 seconds and afterwards stirred for 24 h on a magnetic stirrer. Finally undissolved particles of the test substance were removed by filtration.
- Controls: 1 control
- Test concentration separation factor: 2
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): None after filtration

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Age at study initiation (mean and range, SD): Neonates
- Stage and instar at study initiation: Neonates
- Method of breeding: well-established test culture
- Source: Strain of Bundesgesundheitsamt Berlin
- Feeding during test: No

ACCLIMATION
- Acclimation conditions (same as test or not): The culture water (so-called 'M4 medium') is partly renewed once a week.
- Type and amount of food: The Daphnia are exclusively fed with unicellular green algae (Desmodesmus subspicatus) 'ad libitum'.
- Feeding frequency: daily

METHOD FOR PREPARATION AND COLLECTION OF EARLY INSTARS OR OTHER LIFE STAGES, INCLUDING CULTURING CONDITIONS: The neonates are separated from their parent Daphnia by filtration prior to the acute test.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

15.8 °dH (= 282 mg/L CaCO3)

Test temperature:

20.0 °C

pH:

7.7 - 7.8

Dissolved oxygen:

8.8. - 9.1 mg O2/L

Nominal and measured concentrations:

0.06, 0.13,0.25, 0.5 and 1 mg/L (nominal)

Details on test conditions:

TEST SYSTEM
- Test vessel: Karlsruher Flaschen holding 10 neonates in 250-300 mL of test medium
- Type (delete if not applicable): closed
- Volume of solution: 250-300 mL
- Aeration: No aeration
- No. of organisms per vessel: 10 neonates per vessel
- No. of vessels per concentration (replicates): 2 replicates per concentration
- No. of vessels per control (replicates): 2 replicates per control

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reconstituted water (M4-medium)

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16:8 light:dark
- Light intensity: < 1000 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : immobilisation after 24 and 48 h

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

0.97 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

>= 0.24 - <= 0.97 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

0.24 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Validity criteria for the measurement of the short-term toxicity to aquatic invertebrates:

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.	Neonates were used in this test.	Yes
In the control, including 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)	In the control 0% mortaility an no other adverse effects were observed.	Yes
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.	Five test concentrations were used. EC0 and EC100 were determined. The test concentration separation factor was 2.	Yes

 

Validity criteria fulfilled:

yes

Remarks:

See 'Any other information on results incl. tables'.

Conclusions:

EC50 (48 h): >0.24 - <0.97 mg/L (nominal)

Executive summary:

The Daphnia were exposed to a range of concentrations, nominally 0.06, 0.13, 0.25, 0.5 and 1 mg/L of the test substance dissolved in water. Auxiliaries used to prepare the testmedia were an ultras turrax, a magnetic stirrer and a folded filter. Observations were made on the swimming ability and the immobilisation rate, respectively, after 24 and 48 hours of exposure. The following values were determined: EC0 = 0.24 mg/L, EC50: >0.24 - <0.97 mg/L, EC100 = 0.97 mg/L (48 h).

The results are expressed in terms of nominal concentrations (at 24 h), and in terms of mean measured concentrations (at 48 h). Measured concentrations ranged from 90 - 96.6% of nominal values at 0 hours, and from 91.7 - 97.6% of nominal values at 48 hours, respectively.

Description of key information

The Daphnia were exposed to a range of concentrations, nominally 0.06, 0.13, 0.25, 0.5 and 1 mg/L of the test substance dissolved in water. Auxiliaries used to prepare the testmedia were an ultras turrax, a magnetic stirrer and a folded filter. Observations were made on the swimming ability and the immobilisation rate, respectively, after 24 and 48 hours of exposure. The following values were determined: EC0 = 0.24 mg/L, EC50: >0.24 - <0.97 mg/L, EC100 = 0.97 mg/L (48 h).

The results are expressed in terms of nominal concentrations (at 24 h), and in terms of mean measured concentrations (at 48 h). Measured concentrations ranged from 90 - 96.6% of nominal values at 0 hours, and from 91.7 - 97.6% of nominal values at 48 hours, respectively.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

> 0.24 - < 0.97 mg/L