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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:
20/01-2015 - 27/01/2015
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
in accordance with GLP

Data source

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

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.2 (Acute Toxicity for Daphnia)
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid
Details on test material:
- Name of test material (as cited in study report): Guaiacwood essential oil
- Physical state: solid
- Storage condition of test material: At room temperature
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
Not relevant

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations: nominal WAFs of 1.0, 2.2, 4.6, 10 and 22 mg/l
- Sampling method: 50-60 ml Samples for possible analysis were taken from all test concentrations and the control at t=0h and t=48h. At the end of the exposure period, the replicates were not pooled at each concentration before sampling, instead samples were taken from replicate A of each group.
- Sample storage conditions before analysis: Samples were stored in a refrigerator until analysis. Additionally, reserve samples of 50 ml were taken for possible analysis. If not used, these samples were stored in a freezer for a maximum of three months after delivery of the draft report, pending on the decision of the sponsor for additional analysis.

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The batch of Guaiacwood essential oil tested was a yellowish/brown solid and a mixture of components with poor water solubility.
Water Accommodated Fractions (WAFs) were prepared at individual loading rates ranging from 1.0 to 22 mg/l. Exact amounts of test substance were added to test medium and magnetically stirred for 2 days in closed vessels with minimal headspace. Thereafter, all solutions were left to stabilise overnight. Subsequently, the WAFs were collected by siphoning the water phase and distributed over the test vessels.
- Controls: yes, blanks

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Daphnia magna
For the test selection of young daphnids with an age of < 24hours, from parental daphnids of more than two weeks old
- Strain: Straus, 1820
- Source: In-house laboratory culture with a known history
- Method of breeding: each batch was started with newborn daphnids in M7 medium, i.e. less than 3 days old, by placing about 250 of them into 5 litres of medium in an all-glass culture vessel. Maximum age of cultures is 4 weeks. Daphnids are kept at 18-22ºC and were fed an algal suspension on a daily basis.
- Feeding during test: No

ACCLIMATION
- Health during acclimation (any mortality observed): Daphnids originated from a healthy stock, 2nd to 5th brood, showing no signs of stress such as mortality >20%, presence of males, ephippia or discoloured animals and there was no delay in the production of the first brood.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Post exposure observation period:
Not relevant

Test conditions

Hardness:
180 mg/l CaCO3
Test temperature:
20 - 21ºC
pH:
7.6 - 7.9
Dissolved oxygen:
8.0 - 9.2 mg/l
Salinity:
Not relevant
Nominal and measured concentrations:
Nominal: control, 1.0, 2.2, 4.6, 10 and 22 mg/l (WAF)
Measured (t=0h): 1.022, 1.0787, 2.597, 4.472, 7.062 and 10.57 mg/l
Measured (t=48h): 0.5222, 0.8819, 1.605, 3.878, 6.02 and 9.638 mg/l
Details on test conditions:
TEST SYSTEM
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: 60 ml, all-glass, with a minimum headspace, closed airtight
- Aeration: None
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: tap water purified by Reverse Osmosis (RO-water, GEON Waterbehandeling, Berkel-Enschot, The Netherlands)
- Composition:
CaCl2.2H2O 211.5 mg/l
MgSO4.7H2O 88.8 mg/l
NaHCO3 46.7 mg/l
KCl 4.2 mg/l
B 0.125 mg/l
Fe 0.05 mg/l
Mn 0.025 mg/l
Li, Rb and Sr 0.0125 mg/l
Mo 0.0063 mg/l
Br 0.0025 mg/l
Cu 0.0016 mg/l
Zn 0.0063 mg/l
Co and I 0.0025 mg/l
Se 0.0010 mg/l
V 0.0003 mg/l
Na2EDTA.2H2O 2.5 mg/l
Na2SiO3. 9H2O 10.0 mg/l
NaNO3 0.27 mg/l
KH2PO4 0.14 mg/l
K2HPO4 0.18 mg/l
Thiamine 75.0 μg/l
B12 1.0 μg/l
Biotin 0.75 μg/l
- Culture medium different from test medium: No
- Intervals of water quality measurement: temperature (continuously), pH and oxygen (after 0 and 48 hours)

OTHER TEST CONDITIONS
- Photoperiod: 16 hours daily

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): immobility at 24 and 48 hours

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2.2
- Range finding study
- Test concentrations: 1.0, 10 and 100 mg/l
- Results used to determine the conditions for the definitive study: yes
Reference substance (positive control):
yes
Remarks:
Potassium dichromate

Results and discussion

Effect concentrationsopen allclose all
Duration:
24 h
Dose descriptor:
EL50
Effect conc.:
12 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: 95% CL: 10-16 mg/l
Key result
Duration:
48 h
Dose descriptor:
EL50
Effect conc.:
5 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: 95% CL: 4.3 - 6.3 mg/l
Details on results:
- Other biological observations: The responses recorded in this test allowed for reliable determination of an EL50. No immobilisation was observed in the control and the two lowest concentrations during the exposure. In the WAF prepared at 4.6 mg/l 40% daphnids were immobilised at the end of the exposure. All daphnids were immobilised in the two highest concentrations at the end of the test.
- Mortality of control: 0%
Results with reference substance (positive control):
- Results with reference substance valid? Yes
- Mortality: 100%
- 24-EC50: 0.93 mg/l
- 48h-EC50: 0.47 mg/l
Reported statistics and error estimates:
The 24 and 48h-EL50-value was calculated from the weibits of the percentages of affected daphnids and the logarithms of the corresponding loading rates using the maximum likelihood estimation method.

ToxRat Professional v 2.10.05 (ToxRat Solutions® GmbH, Germany) was used to perform the analyses.

Any other information on results incl. tables

Number of introduced daphnids and incidence of immobility in the final test

Time (h)

Replicate

Guaiacwood essential oil, WAF prepared at (mg/l)

Control

1.0

2.2

4.6

10

22

0

A

5

5

5

5

5

5

B

5

5

5

5

5

5

C

5

5

5

5

5

5

D

5

5

5

5

5

5

Total introduced

20

20

20

20

20

20

24

A

0 (1)

0

0

0 (5)

1 (5)

5 (4)

B

0

0 (1)

0

0 (5)

1 (4)

5 (5)

C

0

0

0 (1)

0 (5)

1 (4)

5 (5)

D

0

0

0

0 (5)

2 (5)

5 (5)

Total immobilised

0

0

0

0

5

20

Effect %

0

0

0

0

25

100

 

 

 

 

 

 

48

A

0

0

0

0

5 (2)

5

B

0 (1)

0 (2)

0

1

5 (2)

5

C

0

0

0

2

5 (1)

5

D

0

0 (1)

0

5 (2)

5

5

Total immobilised

0

0

0

8

20

20

Effect %

0

0

0

40

100

100

( ) between brackets: number of daphnia observed trapped at the surface of the test solutions. These organisms were reimmersed into the respective solutions before recording of mobility.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
Mortality in controls 0%, oxygen >3 mg/l at the end of the test
Conclusions:
The acute toxicity (48h-EL50) of Guaiacwood essential oil towards Daphnia magna is 5 mg/l.
Executive summary:

The acute toxicity of Guaiacwood essential oil towards Daphnia magna was investigated according to OECD guideline 202 under GLP. Daphnids were exposed to nominal WAFs of 1.0, 2.2, 4.6, 10 and 22 mg/l and were observed for 48 hours. Based on nominal concentrations, the 48h-EL50 was found to be 5 mg/l.