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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:
Jan 05, 1994 - May 10, 1994
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1994
Report Date:
1994

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent

Sampling and analysis

Analytical monitoring:
yes

Test solutions

Vehicle:
no
Details on test solutions:
For the preliminary test, a stock solution [A] containing 10 g/l of the test article in a solution was prepared by adding the required amount of the test article to test medium. This solution was agitated for 15 min in an ultrasonic water bath and subsequently on a magnetic stirrer. Concentration levels at or above 10.0 mg/l were achieved by dilution of the stock solution with Elendt medium by a factor of 10.
For the main test, a stock solution containing 100 mg/l of the test article was prepared as described above. The actual test concentrations were achieved by dilution of the stock solution with Elendt medium. Five concentrations between 10 mg/l and 0.6 mg/l were prepared using a serial dilution factor of 2. Additionally a concentration level of 7.5 mg/l was introduced.

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
Prior to testing, the daphnia were held in groups of 25-30 organisms in 1000 ml glass vessels containing synthetic water (Blendt medium). They were fed every 24 h with unicellular green algae (Scenedesmus spp.) and the water was renewed routinely on Monday, Wednesday and Friday.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h

Test conditions

Hardness:
sum of calcium and magnesium ions: 2.5 mmol/L
14.5 °dH
Test temperature:
19.6 - 21.6°C
pH:
7.5 - 8.5
Dissolved oxygen:
The lowest concentration of dissolved oxygen at the end of the test was 7.9 mg/L
Salinity:
not applicable
Conductivity:
0.049 µS/cm
Nominal and measured concentrations:
Analytical control measurements indicated that the measured concentrations did not significantly differ from the nominal concentrations. Analysis were performed by the sponsor
(data presented in APPENDIX ill).
Details on test conditions:
For each concentration, four 25 ml volumetric cylinders were filled with 10 ml of the appropriate test article solution. Subsequently, five daphnia were added to each test vessel.
The test vessels were closed and placed in a thermostatted incubator. The test was performed under standardized, constant conditions. In the preliminary test, the daphnia were observed after 48 h of exposure, while in the main test, observations were performed at 24 h and 48 h. In each case, two reference groups exposed to two concentration levels (0.4 and 1.4 mg/l) of the reference substance K2Cr2O7 and one control group were run concurrently.
On the basis of the results of the preliminary test, a concentration range between 10 mg/l and 0.6 mg/l was selected for the main test. The dilutions were performed stepwise by a factor of 2. A concentration level of 7.5 mg/l was used additionally.
Reference substance (positive control):
yes
Remarks:
K2Cr2O7

Results and discussion

Effect concentrationsopen allclose all
Duration:
24 h
Dose descriptor:
EC50
Effect conc.:
6.7 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
3.7 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
1.25 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Details on results:
In comparison to the control group, no obvious abnormal effects were seen at or below a concentration of 1.25 mg/l, which is therefore considered to represent the NOEC of the test
article.
Results with reference substance (positive control):
Potassium dichromate K2Cr2O7 (CAS No. 7778-50-9) was used as positive control in a current reference study.
Reported statistics and error estimates:
The 48 h EC50 value of 3.7 mg/l on the basis of nominal concentrations was calculated by means of Probit analysis according to Finney (1971) after log transformation of the nominal concentration values.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
Under the conditions of the study a 48-hour EC50 value of 3.7 mg/L and a NOEC of 1.25 mg/L have been determined for the effects of the test substance on mobility of Daphnia magna based on nominal exposure concentrations of the substance.