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Short-term toxicity to aquatic invertebrates

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Reference
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
other: read across from analogue substance
Adequacy of study:
key study
Study period:
Since July 15, 1997 until September 3,1997
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Qualifier:
according to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Analytical monitoring:
yes
Details on sampling:
All test medium samples for the analytical determinations were taken from the approximate centre of the test vessels (after mixing the medium) and kept at -18°C to -25°C until analysis. The concentrations of the test substance at the beginning and at the end of the test were analysed by spectrophotometric method.
The samplesw eres tored at room temperature




Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
-Stock solution: 100.1 mg test substance were mixed with 200 ml test medium in a beaker and filled up to 1000 ml with test water. The stock solution was homogenised by ultrasonic treatment for 5 minutes. The test concentrations were prepared from this stock solution.
- Test solutions: A range finding test was carried out at concentrations from 0.01 - 100 mg/1 to determine the concentrations for the main test.
Due to the results of this pre-test the nominal test concentrations were chosen as 45 and 100 mg test substance/1. Additionally a blank control without test substance was tested.

- Evidence of undissolved material (e.g. precipitate, surface film, etc): Observation of sediments in the test vessels. The high content of salts in the test medium may have been caused a decrease of solubility of the test substance.
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Daphnia magna
- Strain: Straus
- Source: The Daphnia were bred in the laboratories of the Product Ecology under standardised conditions.
- Feeding during test: with a suspension of green algae (Scenedesmus subspicatus) supplemented by a Tetramin-extract .
- Food type: green algae (Scenedesmus subspicatus) supplemented by a Tetramin-extract
- Amount: in such quantities that the food is consumed within 24 hours

For each test concentration 20 Daphnia divided into two groups of 10 animals were used.


Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Hardness:
Total hardness = 259 mg/l CaCO3

Test temperature:
20,0 °C
pH:
The pH was in a range of 7.6 - 8.0.
The pH 8.1 (in the highest test concentration ).
Dissolved oxygen:
The test medium was oxygen saturated at the beginning of the test.
Oxygen (%) in:
Blank= 98
45mg/l of nominal conc.= 98
100mg/l of nominal conc.=96
Salinity:
NaHCO 65 mg/l
MgS04 * 7H20 123.3 mg/l
KCl 5.8 mg/l
CaCl2 x 2H20 294 mg/l
Na2Si03 4.3 mg/l
NaN03 274 µg/l
KH2PO4 143 µg/l
K2HPO4 184 µg/l
Nominal and measured concentrations:
During the test the actual test concentrations in the analysed test media were in the range of 24.8 - 26.4% of the nominal values. Therefore, the results are related to the actual values of the test substance concentrations.
The relatively low recovery of 24.8 - 26.4 % correlates with the observation of sediments in the test vessels. The high content of salts in the test medium may have been caused a decrease of solubility of the test substance.
Details on test conditions:
TEST SYSTEM
- Test vessel: 250 ml beakers containing 60-100 ml test medium with 10 animals per beaker. All tests were run in duplicate.
- Renewal rate of test solution: The water is renewed partially three times per week.
- No. of organisms per vessel:10
- No. of vessels per concentration (replicates):2
- No. of vessels per control (replicates):2


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: The test medium was prepared with bidistilled water.
- Metals: Na+, Mg2+, K+, Ca2+
- Alkalinity:0.8 mmol/l
- Ca/mg ratio: 4:1
-Na / K ratio 10 : 1

OTHER TEST CONDITIONS
- Light intensity:14 hours photoperiod daily, 10 hours darkness

- Test concentrations: 45 and 100 mg/l nominal
Reference substance (positive control):
yes
Remarks:
potassium dichromate
Duration:
48 h
Dose descriptor:
other: IC0
Effect conc.:
ca. 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
IC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
IC100
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
The evaluation were done according to the guidelines by visual assessment of the mobility of the Daphnia after 24 and 48 hours. The relatively low recovery of 24.8 - 26.4 % correlates with the observation of sediments in the test vessels. No immobilization and abnormal behaviour of the Daphnia was observed in the test concentration of 26 mg/l, which is the solubility limit of the nominal concentration 100 mg/l, after the test period of 48 hours.
Results with reference substance (positive control):
- Results with reference substance valid? Yes
- EC50/LC50: 1.07 mg/l after 24h
- reference control July 03,1997
Reported statistics and error estimates:
If possible the EC50 values and the confidence limits were calculated with the "Program for the computation of the ED50" revised November 1988 (V.I.2.), Ciba-Geigy AG; W.Seewald, Mathematical Applications / FO 5.31.
Validity criteria fulfilled:
yes
Conclusions:
The substance was tested for acute toxicity to Daphnia following OECD 202. Under the experimental conditions the IC50, 48h (IC0) is > 100 mg/l (nominal, 26 mg/l measured, solubility limit of the substance in the test conditions)
Executive summary:

The analogue substance was tested for acute toxicity to Daphina Magna following OECD 202, Immobilisaton test. During the test the actual concentrations in the analysed test media were in the range of 24,8 -26 ,4% of the nominal values (100 mg/l). The relatively low recovery of the tested substance correlates with the observation of sediments in the test vessels. The high content of salts in the test medium may have caused a decrease in solubility of the test substance. No immobilisation and abnormal behaviour of the Daphnia were observed in the test concentration of 26 mg/l after the test period of 48 hours. Therefore the IC0, 48h = 26 mg/l and IC50, 48h > 26 mg/l.

Description of key information

analogue substance 1, IC0, 48h = 100 mg/l and IC50, 48h > 100 mg/l (nominal), >26 mg/l (measured)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Effect concentration:
100 mg/L

Additional information

One study (1997, Ciba) was performed on analogue substance 1 for acute toxicity to Daphina Magna following OECD 202, Immobilisaton test. During the test the actual concentrations in the analysed test media were in the range of 24,8 -26 ,4% of the nominal values (100 mg/l). The relatively low recovery of the tested substance correlates with the observation of sediments in the test vessels. The high content of salts in the test medium may have caused a decrease in solubility of the test substance. No immobilisation and abnormal behaviour of the Daphnia were observed in the test concentration of 26 mg/l after the test period of 48 hours. Therefore the IC0, 48h = 26 mg/l and IC50, 48h > 26 mg/l.