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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:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
GLP compliance:
yes (incl. certificate)
Analytical monitoring:
yes
Details on sampling:
Since the test item is an unspecified mixture, an unspecific method was considered to be appropriate. The test concentrations were below the limit of quantification. Therefore the stable distribution over the exposure period was representatively determined in a stock solution exposed to study conditions. In the freshly prepared stock solution 3.8 mg Carbon/L could be detected. After 48 h the content of Carbon was 3.3 mg/L. All reported results refer to nominal concentrations.
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The test concentrations were prepared by dilution of the stock solution of a concentration of 10 mg test item/L directly before the start of exposure. A stock solution of 10 mg test item/L was prepared by dissolving 25.0 mg test item into 2500 mL test water by intense stirring for 10 minutes. Adequate volumes of this stock solution were diluted with test water to prepare the test media.
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Daphnia magna
- Strain: clone 5
- Source: The daphnids introduced in the test were taken from the inhouse laboratory culture.
- Age at study initiation (mean and range, SD): 2.0 to 18.5 hours old

- Method of breeding: The daphnids were bred in the laboratory under similar temperature and light conditions as used in the test. The cultivation of the parental daphnids was performed in the same reconstituted water as the test water used in the test. The test organisms were not
first brood progeny.
-The daphnids in the stock culture were fed at least on all working days with green algae (Desmodesmus subspicatus) freshly grown in the laboratory.

ACCLIMATION
- Was not necessary, since the test was performed in the same medium as the culturing.
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Test temperature:
20 °C
pH:
7.9 to 8.2
Dissolved oxygen:
8.3 to 9.3 mg/L
Nominal and measured concentrations:
Nominal test concentrations: control 47.6, 85.7, 154, 278 and 500 μg test item/L
Details on test conditions:
TEST SYSTEM
- Test vessel: Glass beakers
- Type: covered with a lid to reduce the loss of water due to evaporation and to avoid the entry of dust into the solutions
- Size, fill volume: 100 mL, 60 mL
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

OTHER TEST CONDITIONS
- Photoperiod: 16 h light - 8 h dark
- Light intensity: 590 - 800 lux

EFFECT PARAMETERS MEASURED: Immobilisation was recorded after 48h.

TEST CONCENTRATIONS
- Range finding study: yes, non-GLP
- Test concentrations: 47.6, 85.7, 154, 278 and 500 μg test item/L
- Results used to determine the conditions for the definitive study: yes
Reference substance (positive control):
yes
Remarks:
potassium dichromate
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
0.138 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
- In the freshly prepared stock solution 3.8 mg Carbon/L could be detected. After 48 h the content of Carbon was 3.3 mg/L.
- After 24 hours in the control and in the concentrations up to and including 154 μg test item/L no immobilisation of the test animals was observed. - At the highest test concentrations of 278 and 500 μg/L 6 respectively 20 daphnids were immobile after 24 hours test duration.
- At the end of the test the toxicity of the test item to Daphnia magna had increased.
- After 48 hours of exposure no immobilisation of the test animals was observed in the control and up to and including the test item concentration of 85.7 μg/L.
- At the concentration of 154 μg/L, 17 daphnids were immobile.
- At the highest test item concentrations of 278 and 500 μg/L, 21 and 20 daphnids were immobile, respectively.
Results with reference substance (positive control):
- The reference item potassium dichromate is tested at least twice a year to demonstrate satisfactory test conditions.
Validity criteria fulfilled:
yes
Conclusions:
The test substance is acutely very toxic to aquatic invertebrates.

Description of key information

EC50(48h) = 0.138 mg/L (nominal) for immobilisation of Daphnia magna (OECD 202)

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
0.138 mg/L

Additional information

The acute toxicity on aquatic invertebrates was investigated for the Sulfonium compound mixture with the waterflea Daphnia magna, in a GLP guideline study according to OECD 202 (BASF 2013). After 48 hours the EC50 for immobilisation was 0.138 mg/L based on nominal test substance concentration.