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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
Study period:
May 2004
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Even if the study is not GLP, it follows the standard recognised guidelines (EC C2 and OECD 202), but without analytical monitoring.
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
no
Qualifier:
equivalent or similar to guideline
Guideline:
EU Method C.2 (Acute Toxicity for Daphnia)
Deviations:
no
GLP compliance:
no
Analytical monitoring:
no
Vehicle:
no
Details on test solutions:
Test medium:
The test medium was reconstituted water and its characteristics are described below:
Total hardness: between 40 and 48mg/L in CaCO3.
Conductivity: between 190-250 μS/cm
pH: between 7,2 and 7,6
The test medium was aerated before the test until the saturation was reached.

Test solutions:
The day before the test, solutions of 100mg/L, 10mg/L and 1mg/L of the test substance were prepared in the test medium. The solutions were continuously stirred for 24 hours at approximately 25ºC. However, the solutions were brought to 20ºC before starting the test.
On the day of the test, the soluble fractions of each one of the four solutions were separated by decantation, during 2 hours. After that, they were introduced into the test bottles.
The concentrations of the test solutions are expressed in mg of test item per liter of test medium.
At the end of the test, the test solutions were collected
Test organisms (species):
other: Daphnia similis
Details on test organisms:
TEST ORGANISM
- Common name: Daphnia similis
- Strain: Claus 1876 (Cladocera Crustacea).
- Source: CETESB (Companhia de Tecnologia e Saneamento Ambiental)
- Age at study initiation (mean and range, SD): < 24h old
- Feeding: unicellular green alga Selenastrum capricornutum and fish feed, once a day.
- Feeding during test: no

ACCLIMATION
- Acclimation period: none


Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Hardness:
40-48 mg/L
Test temperature:
19.7-20.0 ± 0.5ºC
pH:
6.98 - 7.49
Dissolved oxygen:
6.25 - 7.37 mg/L
Nominal and measured concentrations:
1.0; 10 and 100 mg/L.
Details on test conditions:
TEST SYSTEM
- Test vessel: 40ml-pyrex glass tubes (borosilicate glass).
- Type (delete if not applicable): open
- Aeration: The test medium was aerated before the test until the saturation was reached.
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

Four test solutions were prepared at the following concentrations: 1, 10 and 100 mg/L. The concentration of 100 mg/L was prepared in duplicate (100A and 100B).
10mL of each soluble fraction of the test solutions were transferred in each one of four test containers per concentration and 10mL of the test medium were introduced in each of four test containers for the control.
Five organisms in each of the test containers were added - 20 daphnia at the total for each concentration and control (it took approximately 15 minutes for all the containers).


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reconstituted water
- Culture medium different from test medium: no

OTHER TEST CONDITIONS
- Adjustment of pH: yes
- Photoperiod: none
- Light intensity: darkness

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : After 24 and 48 hours of daphnia exposure, immobilized daphnia were counted in each test container.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 10
Reference substance (positive control):
yes
Remarks:
Potassium dichromate
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 1 - < 10 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
The acute toxicity of isobornylcyclohexanol to Daphnia similis in 24 and 48 hours is between 1 and 10 mg/L.
The acute toxicity zone of isobornylcyclohexanol to Daphnia similis in 24 hours is comprised between 1 and 10 mg/L. The highest tested concentration causing a percentage of immobilization ≤ 10 % is 1mg/l. The lowest tested concentration causing 100 % immobilization is 10 mg/L.
The acute toxicity zone of isobornylcyclohexanol to Daphnia similis in 48 hours is comprised between 1 and 10 mg/L. The highest tested concentration causing a percentage of immobilization ≤ 10 % is 1mg/l. The lowest tested concentration causing 100 % immobilization is 10 mg/L.

Validity criteria were fulfiled:
In the control, not more than 10% of the Daphnia was immobilized or trapped at the surface of the water.
The dissolved oxygen concentration at the end of the test was greater than 2 mg/L.
The pH didn’t change by more than 1,5 unit during the period of the test.
Results with reference substance (positive control):
The daphnia had a 24 H - EC 50 with potassium dichromate of 0,29mg/l.
This result is in accordance with the control chart of the laboratory.

Physico-chemical parameters:

Initial

Number of Mobile Organisms

pH

O2

Concentration

Tube 1

Tube 2

Tube 3

Tube 4

mg/L

(mg/L)

24h

48h

24h

48h

24h

48h

24h

48h

Initial

Final

Initial

Final

100 A

0

0

0

0

0

0

0

0

7,34

7,06

7,22

7,37

100 B

0

0

0

0

0

0

0

0

7,32

7,05

7,03

6,97

10

0

0

0

0

0

0

0

0

7,35

6,98

7,13

6,25

1

5

4

5

4

5

5

5

5

7,41

7,00

7,35

6,34

Control

5

5

5

5

5

5

5

5

7,49

7,21

7,04

6,98

 

 

Initial Concentration

Immobile Organisms

24h

Immobile Organisms

48h

(mg/L)

Total number

%

Total number

%

100 A

20

100

20

100

100 B

20

100

20

100

10

20

100

20

100

1

0

0

2

10

Control

0

0

0

0

Results with potassium dichromate:

Initial Concentration

Number of Mobile Organisms 24h

Total Immobile

pH

O2

mg/L

(mg/L)

Tube 1

Tube 2

Tube 3

Tube 4

Organisms

Initial

Final

Initial

Final

0,59

0

0

0

0

20

7,29

7,35

7,52

7,78

0,46

0

0

0

0

20

7,31

7,31

7,49

7,79

0,35

0

0

0

0

20

7,29

7,25

7,51

7,81

0,27

4

4

3

4

5

7,25

7,29

7,22

7,81

0,21

5

5

5

5

0

7,31

7,24

7,21

7,82

0,16

5

5

5

5

0

7,41

7,25

7,31

7,91

0,12

5

5

5

5

0

7,48

7,31

7,25

7,92

Control

5

5

5

5

0

7,60

7,31

7,42

7,62

Validity criteria fulfilled:
yes
Conclusions:
With a EC50-48h between 1 and 10 mg/L, isobornylcyclohexanol is toxic for daphnia.
Executive summary:

The objective of this study (2004) was to determine, through a screening test, the acute toxicity zone of isobornylcyclohexanol (CAS: 3407-42-9) to Daphnia similis.

The day before the test, solutions of 100mg/L, 10mg/L and 1mg/L of the test substance were prepared in the test medium. The solutions were continuously stirred for 24 hours at approximately 25ºC. However, the solutions were brought to 20ºC before starting the test.

On the day of the test, the soluble fractions of each one of the four solutions (the concentration of 100mg/L was prepared in duplicate) were separated by decantation during 2 hours. After that, they were introduced into the test bottle. Four replicates with five animals were investigated at the exposure levels of 100A mg/L, 100B mg/L, 10 mg/L and 1 mg/l.

The concentration zones of the 24-hour EC(I)50 and 48-hour EC(I) 50 are described below:

EC(I)50-24 hours = between 1 and 10 mg/L

EC(I)50-48 hours = between 1 and 10 mg/L

Based on these results, isobornylcyclohexanol is toxic to Daphnia.

Description of key information

The test item, isobornylcyclohexanol, was considered toxic to Daphnia similis.

The 48-hour EC50 of isobornylcyclohexanol to Daphnia similis was thus determined to be between 1 and 10 mg/L based on the mobility; revealing it is toxic for the daphnids.

Key value for chemical safety assessment

Additional information

A screening study, scored as Klimisch 2 and flagged as a key study, is available on isobornylcyclohexanol, giving a 48h-EC50 between 1 and 10 mg/L and revealing that isobornylcyclohexanol is toxic to Daphnia similis (T. Arruda, 2004).

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