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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From December 12, 2003 to February 4, 2004
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study performed according to OECD and according to GLP

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2004
Report Date:
2004

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.2 (Acute Toxicity for Daphnia)
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- For the determination of the actual test item concentration, the following samples were taken:
- Just before the start of the test: duplicate samples from the test medium and from the control (both without daphnids)
- After 48 hours (stability samples): duplicate samples from the test medium and from the control

- For the 48-hour stability samples, addifional flasks with adequate volumes of the freshly prepared test medium and the control were incubated during the test period under the same conditions as in the actual test (but without daphnids). All samples were directly analyzed after sampling without prior storage.

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A water accomodated fraction (WAF) with a loading rate of 100 mg/L was prepared according to the OECD Guidance Document on Aquatic Toxicity Testing of Difficult Substance or Mixtures.
- A dispersion with the loading rate of 100 mg/L was prepared by mixing 250.8 mg of the test item into 2500 mL test water.
- No auxiliary solvent or emulsifier was used.
The dispersion was treated ultrasonically for 15 minutes and stirred for 96 hours at room temperature in the dark to dissolve a maximal amount of the test item in test water. After the stirring period, the saturated dispersion was filtered through a membrane filter (Schleicher & Schuell, Type NC45, pore size 0.45 microm) just before the start of the test. The undiluted filtrate was tested on daphnids as WAF
- Controls: yes, growth medium without test item
- Evidence of undissolved material: clear test medium during the whole test

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Daphnia magna
- Source: A cone of this species was originally supplied by the University of Sheffield/UK in 1992. Since that time, the clone is bred in the laboratories of RCC
- Age at study initiation: 6-24 h
- Method of breeding: in RCC laboratories in reconstituted water of the quality identical to the water quality used i the tests (regarding pH, main ions and total hardness)

Study design

Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
48 h

Test conditions

Hardness:
2.5 mmol/L (= 250 mg/L as CaCO3)
Test temperature:
20°C during the test period (test performed in a temperature-controlled room)
pH:
7.7-7.9
(start: pH = 7.8 for control and 7.7 for the loading rate / end: pH = 7.9 for control and loading rate)
Dissolved oxygen:
Start of the test: 9.0 mg/L
End of the test: 8.9 mg/L
Nominal and measured concentrations:
Loading rate of 100 mg/L
Measured concentration: < LOQ (0.0024 mg/L)
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type: the beakers were covered with glass plates to reduce the loss of water and to avoid the entry of dust
- Material, size, headspace, fill volume: 100 mLglass beakers
- Aeration: non
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- Biomass loading rate: < 1 daphnia per 2 ml of test solution

TEST MEDIUM / WATER PARAMETERS
Test water:
- Reconstituted test water: analytical grade salts were dissolved in purified water to obtain the following nominal concentrations:
- CaCl2 x 2H2O: 2.0 mmol/L (= 294.0 mg/L)
- MgSO4 x 7 H2O : 0.5 mmol/L (= 123.0 mg/L)
- NaHCO3: 0.75 mmol/l (= 65.0 mg/L)
- KCl: 0.075 mmol/L (= 5.8 mg/L)
- Alkalinity: 0.8 mmol/L
- Ratio of Ca:Mg = 4:1 (based on molarity)
- Ratio of Na:K = 10:1 (based on molarity)
- Culture medium different from test medium: no
- Intervals of water quality measurement: 24h

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: a 16-hour light to 8-hour dark photoperiod with a 30-minute transition period
- Light intensity: between approximately 520-710 Lux

EFFECT PARAMETERS MEASURED: Immobilization (every 24h)

TEST CONCENTRATIONS
- Range finding study: yes
- Results used to determine the conditions for the definitive study: yes
Reference substance (positive control):
yes
Remarks:
potassium dichromate (tested at least once a year)

Results and discussion

Effect concentrationsopen allclose all
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
24 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
- Mortality of control: none
- Appearance of the test medium: No remarkable observations were made concerning the appearance of the tes medium: the test medium was a clear solution throughout the entire test duration

Any other information on results incl. tables

In the control and in the WAF with the loading rate of the test item of 100 mg/L, no immobilzed test organisms were observed during the test period of 48h. Therefore, the 48-hour NOEC and the 48-hour EC0 of the test substance to Daphnia magna were determined to be at least the loading rate of 100 mg/L. The 48-hour NOEC and EC0 may even be higher but loading rates above 100 mg/L or test item concentrations above the solubility limit in test water were not tested. The 48-hour EC50 and the 48-hour EC100 were clearly higher than the loading rate of 100 mg/L. These values could not be quantified since the test item had no toxic effect on the daphnids up to the loading rate of 100 mg/L or up to the highest test item concentration which could be dissolved in the test water.

Applicant's summary and conclusion