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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:

2007-10-29 to 2007-12-04

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)

Remarks:

certified by "Ministerium für Umwelt und Naturschutz, Landwirtschaft und Verbraucherschutz des Landes Nordrhein-Westfalen", Germany

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 50 and 100 mg test item/L (nominal)
- Sampling method: Freshly prepared media and media after 24 h of exposure
- Sample storage conditions before analysis: at 4 °C until analysis, analysis was routinely performed on the day of sampling

Vehicle:

no

Details on test solutions:

test item was added to reconstituted water (M4 medium)

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Strain/clone: Strain of Bundesgesundheitsamt Berlin (Germany)
- Age at study initiation: less than 24 h old at the beginning of the test
- Sex: Female
- Source: bred in the laboratory
- Food and Feeding: daphnids were fed with concentrated algal suspension of Desmodesmus subspicatus during the holding at libitum; not fed during the exposure

ACCLIMATION
- Test animals were bred under similar (or the same) conditions as that used during the exposure period (holding water, temperature etc.), therefore, additional acclimatisation before the test was not necessary. Brood daphnids were maintained in dilution water at the test temperature for at least 48 hours prior to the start of the test.

Test type:

semi-static

Water media type:

freshwater

Remarks:

Reconstituted water (M4 medium)

Limit test:

no

Total exposure duration:

48 h

Hardness:

266 mg CaCO3/L

Test temperature:

20.1 to 20.8 °C

pH:

7.7 to 7.9

Dissolved oxygen:

8.2 to 8.8 mg/L

Nominal and measured concentrations:

nominal: 0 (control), 50 and 100 mg test item/L
measured: only DOC measurements, please see Table 1 in results section

Details on test conditions:

TEST SYSTEM
- Test vessel: 50 mL glass beakers, fill volume: 20 mL of test medium
- Aeration: none
- Type of test: semi-static
- renewal rate of test solution: every 24 hours
- No. of organisms per vessel: 10 neonates
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reconstituted water (M4 medium); Test item was added to the dilution water and then treated for 60 seconds in an ultra turrax and afterwards stirred for 24 h on a magnetic stirrer. Finally undissolved particles of the test item were removed by filtration using folded filters of pore size 7-12 μm.

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 : 8 hour light-dark
- Light intensity: < 1000 lux during maintenance

RANGE-FINDING STUDY
In order to select appropriate test concentrations for use in the definitive test, a non-GLP preliminary range-finding test was conducted to determine the approximate toxicity of the test item. No details are reported.

Reference substance (positive control):

not specified

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks:

Swimming ability and immobilisation rate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks:

Swimming ability and immobilisation rate

Details on results:

- Behavioural abnormalities: no abnormalities
- Other biological observations: none
- Mortality of control: no mortality
- Other adverse effects control: no
- Immobilisation of control: no immobilisation
- Abnormal responses: none

Results with reference substance (positive control):

not reported

Reported statistics and error estimates:

Not reported.

Table 1: Measured concentrations: DOC value [mg/L]

DOC value [mg/L]	24 h		48 h
	0 h (fresh)	24 h (aged)	0 h (fresh)	24 h (aged)
Control	< 5	< 5	< 5	< 5
50 mg/L test item	12.53	10.62	11.16	9.177
100 mg/L test item	24.76	21.64	20.71	16.74

Table 2: Immobilisation of test animals

Concentration [mg/L]	Number of Daphnia tested	Number of immobilised Daphnia	Number of immobilised Daphnia
		24 h	48 h
Control	20	0	0
50 mg/L test item	20	0	0
100 mg/L test item	20	0	0

VALIDITY OF TEST

No immobilisation was observed in the control group and the dissolved oxygen concentration at the end of the test in control and test vessels was more than 3 mg/L in all cases.
All validity criteria were met, therefore the study is considered to be fully valid.

Validity criteria fulfilled:

yes

Remarks:

The immobilisation and other abnormalities in the controls did not exceed 10% by the end of the test (actual value: 0 %). The dissolved oxygen concentration remained above 3 mg/L throughout the exposure period (actual values: 8.2 - 8.8 mg/L).

Conclusions:

In the acute toxicity test with Daphnia magna according OECD TG 202, the EC50 was estimated to be above the highest tested concentration (> 100 mg test item/L).

Executive summary:

To investigate the acute toxicity of the test item to aquatic invertebrates, a semi-static immobilisation test with Daphnia magna according to OECD TG 202 was carried out in accordance with GLP principles. Twenty animals per treatment and control (divided in 2 replicates with 10 animals in each vessel) were exposed to nominal test item concentrations of 50 and 100 mg/L, respectively. For determination of the test item concentrations, samples were taken from each concentration level and control at the start and at the end of each water renewal period, i.e., after 24 hours of exposure. Concentrations were indirectly determined by measurement of carbon. Carbon dioxide was determined by infrared spectrometry. Biological results and endpoints are based on the nominal concentrations. An untreated control ran in parallel. The immobility or mortality of the Daphnia was determined by visual observation after 24 and 48 hours of exposure. All validity criteria of the test guideline were met, therefore the study is considered to be fully valid. No effects of the test item were found. As a result, the EC₅₀ was estimated to be above the highest tested concentration (> 100 mg test item/L).

Description of key information

In the acute toxicity test with Daphnia magna according OECD TG 202, the EC₅₀ was estimated to be above the highest tested concentration (> 100 mg test item/L). All validity criteria of the test guideline were fulfilled. The study is thus regarded valid.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

> 100 mg/L

Additional information

To investigate the acute toxicity of the test item to aquatic invertebrates, a semi-static immobilisation test with Daphnia magna according to OECD TG 202 was carried out in accordance with GLP principles. Twenty animals per treatment and control (divided in 2 replicates with 10 animals in each vessel) were exposed to nominal test item concentrations of 50 and 100 mg/L, respectively. For determination of the test item concentrations, samples were taken from each concentration level and control at the start and at the end of each water renewal period, i.e., after 24 hours of exposure. Concentrations were indirectly determined by measurement of carbon. Carbon dioxide was determined by infrared spectrometry. Biological results and endpoints are based on the nominal concentrations. An untreated control ran in parallel. The immobility or mortality of the Daphnia was determined by visual observation after 24 and 48 hours of exposure. All validity criteria of the test guideline were met, therefore the study is considered to be fully valid. No effects of the test item were found. As a result, the 48 hour EC50 of the test item was estimated to be > 100 mg/L.