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Diss Factsheets

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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Well documented study according to international accepted guidelines and GLP compliant.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2015
Report date:
2015

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
2-[(2E)-2-(6-Methoxy-3,4-dihydronaphthalen-1(2H)-ylidene)ethyl]-2-methylcyclopentane-1,3-dione
EC Number:
618-321-5
Cas Number:
899-79-6
Molecular formula:
C19H22O3
IUPAC Name:
2-[(2E)-2-(6-Methoxy-3,4-dihydronaphthalen-1(2H)-ylidene)ethyl]-2-methylcyclopentane-1,3-dione
Test material form:
solid: crystalline
Details on test material:
Test item: Methyl-secodione
CAS number: 899-79-6
Molecular formula: C19H22O3
Batch number: L4B021N
Physical state: Solid, crystalline powder
Colour: Beige
Storage: At room temperíture, dry place

Sampling and analysis

Analytical monitoring:
yes

Test solutions

Vehicle:
yes
Details on test solutions:
The preparation of the test solutions was based on the preliminary non GLP range finding test.
Two stock solutions were prepared in the test. The first stock solution was prepared at the beginning of the test and the second fresh stock solution was prepared on the next day. For the stock solutions 100.0 mg of test item was taken into 1 000 ml Elendt M4 medium. The suspensions were stirred for 24 hours. After it the suspensions were filtered. The first 75 ml filtrates were disposed. The concentration of the filtrates (stock solutions) was determined by validated HPLC
method.
The measured concentrations of the stock solution I and II were 10.03 and 11.31 mg/L respectively.
In the case of both stock solutions seven dilution levels were prepared by mixing appropriate volume of Elendt M4 medium and stock solution of the test item. The maximum separation factor between of test vessels was 2.0.

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
Test species: Daphnia magna Straus
Age: < 24 hours neonates
Origin: National Institute of Environmental Health
Culture conditions: The test species is maintained in Elendt M4 medium with culture conditions at 21±1 °C and a light/dark cycle of 16/8 hours with light intensities of less than 1000 Lux. The cultures are fed with centrifugalized green alga (Pseudokirchneriella subcapitata) cells daily at weekdays.

Study design

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

Test conditions

Test temperature:
The temperature of thermostat was recorded daily and registered continuously.
At the start of the test: 21.1 °C
After 24 hours: 21.1 °C
At the end of the test: 21.1 °C
The temperature inside the thermostat at the test vessels was measured and registered continuously.
pH:
The pH was measured at each concentration level at the following time points:
- At the start (day 0, test solution I) from the rest test solution.
- At 24h (day 1/a, test solution I) from each test vessels.
- At 24h (day 1/b, test solution II) from the rest test solution.
- At 48h (day 2, test solution II) from each test vessels.
The measured mean values varied in the range of 7.88 - 8.01.
Dissolved oxygen:
The oxygen concentration was measured at each concentration level at the
following time points:
- At the start (day 0, test solution I) from the rest test solution.
- At 24h (day 1/a, test solution I) from each test vessels.
- At 24h (day 1/b, test solution II) from the rest test solution.
- At 48h (day 2, test solution II) from each test vessels.
The measured mean values varied in the range of 5.87 - 6.14.
Nominal and measured concentrations:
In the test the following nominal concentrations of test solutions were applied:
test solution I.: 10.03; 6.69; 5.02; 3.34; 2.01; 1.17; and 0.84 mg/L
test solution II.: 11.31; 7.54; 5.66; 3.77; 2.26; 1.32; and 0.94 mg/L.
The average measured concentrations:
8.24; 5.46; 4.08; 2.73; 1.65, 0.96 and 0.70 mg test item/L.
Details on test conditions:
The test was maintained under semi-static conditions for a period of 48 hours.
At the start of the study each test vessels contained 50 ml of test solutions I and five young daphnids. In the test four replicates total of 20 animals at each test
concentration level were investigated. The test vessels were covered with plastic lids and were kept in thermostat at 21 ± 1 °C with a 16/8 hours light/dark cycle.
After 24 hours of the start of the test the living young daphnids were replaced into the freshly prepared test solutions II. The new test vessels were continued to incubate in a thermostat at 21 ± 1 °C with a 16/8 hours light/dark cycle for additional 24 hours. Each control vessels containing five young daphnids in Elendt M4 medium were prepared in four replicates and kept under the same semi-static conditions.
The number of immobilised and abnormally behaved daphnids was recorded after 24h. A daphnia is considered to be immobile if it is not able to swim within 15 seconds after a gentle agitation of the test vessel. The daphnids were not fed during the test.
Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Duration:
48 h
Dose descriptor:
EC10
Effect conc.:
1.61 mg/L
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
2.54 mg/L
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
The ECx concentrations were determined by the ToxRat® statistic software.
The NOEC and LOEC were also determined but the results were not conclusive.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
According to this Daphnia magna, Acute Immobilisation Test for Methyl-secodion (CAS No. 899-79-6) the results indicated that the test item is hazardous to the aquatic environment [GHS Acute aquatic hazard Category Acute II. – 48 hr EC50 (for Crustacea) > 1 mg/L but ≤ 10 mg/L].