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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:
2010
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
A specific analytical method could not be found for this substance in water. In addition, the test solutions were loaded at levels above the water solubility limit (water solubility less than 0.9 mg/L at 20 degrees C according to Method A6; model predicted water solubility of 7E-10 mg/L at 25 degrees C); hence the exposure concentrations in this study likely overloaded the carrying capacity of the water resulting in undissolved materials that may have exerted a physical effect on the organisms and confounded the reliability of the study.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2011
Report Date:
2011

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
Details on test material:
- Name of test material (as cited in study report): OS255939
- Physical state: amber coloured viscous liquid
- Storage condition of test material: Room temperature
- Expiration date of the lot/batch: May 10, 2011

Sampling and analysis

Analytical monitoring:
no
Details on sampling:
- Concentrations: 0.1, 0.18, 0.32, 0.56, and 1.0 mg/L
- Sample storage conditions before analysis: Water samples were taken from the control and each loading rate WAF test group (replicates R1-R2 pooled) at 0 and 48 hours for TOC analysis.

Test solutions

Vehicle:
no
Details on test solutions:
Due to the low aqueous solubility and complex nature of the test item the test solutions were prepared as Water Accommodated Fractions. Amounts of the test item were each separately weighed on to a glass microscope slide and suspended at the surface of reconstituted water to give the 0.1, 0.18, 0.32, 0.56 and 1.0 mg/L loading rates respectively. After the addition of the test item, the reconstituted water was stirred by magnetic stirrer using a stirring rate such that a vortex was formed to give a dimple at the water surface. The stirring was stopped after 23 hours and the mixtures allowed to stand for 1 hour.

Evidence of undissolved material (e.g. precipitate, surface film, etc): Microscopic observations made on the WAFs indicated that a significant amount of dispersed test item was present in the water column and hence it was considered justifiable to remove the WAFs by filtering through a glass wool plug. The WAF was removed by mid-depth siphoning (the first 100 ml discarded) to give the loading rate WAFs. Microscopic observations of the WAFs were performed after filtering and showed there to be no microdispersions or particles of test item present.

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Water Flea
- Strain: Daphnia magna
- Source: In house laboratory cultures
- Age at study initiation (mean and range, SD): 1st instar, less than 24 h old
- Weight at study initiation (mean and range, SD): no data available.
- Length at study initiation (length definition, mean, range and SD): no data available.
- Valve height at study initiation, for shell deposition study (mean and range, SD): no data available.
- Peripheral shell growth removed prior to test initiation: no data available.
- Method of breeding: parthenogenesis
- Feeding during test : The daphnids received no food during exposure
- Food type: Not applicable.
- Amount: Not applicable.
- Frequency: Not applicable.

ACCLIMATION
- Acclimation period: Not applicable.
- Acclimation conditions (same as test or not): Not applicable.
- Type and amount of food: Each culture was fed daily with a suspension of algae (Chlorella sp.).
- Feeding frequency: daily
- Health during acclimation (any mortality observed): Not applicable.

QUARANTINE (wild caught)
- Duration: Not applicable.
- Health/mortality: Not applicable.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Post exposure observation period:
The number of immobilised Daphnia and any adverse reactions to exposure were recorded after 24 and 48 hours. The criterion of effect used was that Daphnia were considered to be immobilized if they were unable to swim for 15 seconds after gentle agitation.

Test conditions

Hardness:
The reconstituted water had an approximate theoretical total hardness of 250 mg/l as
CaCO3.
Test temperature:
20+1 degrees C. Water temperature was recorded daily throughout the test.
pH:
There were no treatment related differences in pH. pH values were recorded at the start and termination of the test.
Dissolved oxygen:
There were no treatment related differences in oxygen concentration. Dissolved oxygen concentrations were recorded at the start and termination of the test.
Salinity:
Not applicable.
Nominal and measured concentrations:
Nominal loading rates of 0.1, 0.28, 0.32, 0.56 and 1.0 mg/L
Details on test conditions:
TEST SYSTEM
As in the range finding tests 250 ml glass jars containing 200 ml of test preparation were used. At the start of the test 10 daphnids were placed in each test and control vessels at random in the test preparations. Duplicate test vessels were used for each test and control group. The test vessels were then covered to reduce evaporation and maintained in a temperature controlled room at approximately 21 degrees C with a photoperiod of 16 hours light and 8 hours darkness with 20 minute dawn and dusk transition periods. The daphnids were not individually identified and received no food during exposure and the test vessels were not aerated. The control group was maintained under identical conditions but not exposed to the test item. The test preparations were not renewed during the exposure period.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
The criterion of effect used was that Daphnia were considered to be immobilised if they were unable to swim for approximately 15 seconds after gentle agitation.

-Results used to determine the conditions for the definitive study: Based on the results of the range finding tests the loading rates for the definitive test were assigned. Results of the initial range finding test indicated that significant immobilization occurred at 1.0, 10 and 100 mg/L loading rate WAF so a second range finding test was conducted by exposing daphnids to nominal loading rates of 0.1, 1.0 and 10 mg/L.
Reference substance (positive control):
yes
Remarks:
potassium dichromate (non-concurrent). A positive control used potassium dichromate as the reference item at concentrations of 0.32, 0.56, 1.0, 1.8 and 3.2 mg/L. Exposure conditions and data evaluation for the positive control were similar to those in the

Results and discussion

Effect concentrationsopen allclose all
Duration:
48 h
Dose descriptor:
EL50
Effect conc.:
0.75 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: 0.56 to 1.0 mg/l loading rate WAF
Duration:
48 h
Dose descriptor:
NOELR
Effect conc.:
0.56 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
- Behavioural abnormalities: NDA
- Observations on body length and weight: NDA
- Other biological observations: NDA
- Mortality of control: 0
- Other adverse effects control: None noted
- Abnormal responses: NDA
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: None noted
- Effect concentrations exceeding solubility of substance in test medium: N/A
Results with reference substance (positive control):
- Results with reference substance valid? Yes.
- EC50/LC50:
Exposure of Daphnia magna to the reference item gave a 48 hour EC50 value of 0.75 mg/L (95% confidence limits 0.68 to 0.86 mg/L) and No Observed Effect Concentration of 0.32 mg/L

Any other information on results incl. tables

Cumulative Immobilisation Data in the Definitive Test

Nominal Loading Rate (mg/l)

Cumulative Immobilised Daphnia (Initial Population: 10 Per Replicate)

24 Hours

48 Hours

R1

R2

Total

%

R1

R2

Total

%

Control

0

0

0

0

0

0

0

0

0.1

0

0

0

0

0

0

0

0

0.18

0

0

0

0

0

0

0

0

0.32

0

0

0

0

0

0

0

0

0.56

0

0

0

0

0

0

0

0

1.0

9

9

18

90

10

10

20

100

The results of the chemical analysis using Total Organic Carbon showed that the test preparations at 0 hours had measured test concentrations from 0.99 to 5.50 mg C/l, while measured concentrations in the range of 2.17 to 2.98 mg C/l were obtained at 48 hours.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The acute toxicity of the test material to the freshwater invertebrate Daphnia magna has been investigated and gave a 48-Hour EL50 value of 0.75 mg/l loading rate WAF with 95% confidence limits of 0.56 – 1.0 mg/l loading rate WAF. The No Observed Effect Loading rate at 48 hours was 0.56 mg/l.
Executive summary:

Introduction.A study was performed to assess the acute toxicity of the test item to Daphnia magna. The method followed that described in the OECD Guidelines for Testing of Chemicals No. 202, referenced as Method C.2 of Commission Regulation No. 440/2008.

 

Methods.

A determination of the General Physico-Chemical Properties study conducted on the test material gave a water solubility value for the test material of less than 0.9 mg/L at 20 degrees C according to Method A6 and using calculation methods the water solubility estimate at 25 degrees C is 7E-10 mg/L. Despite extensive method development work a reliable and specific analytical method could not be found for the test item in water.

 

Following preliminary range finding tests, 20 daphnids (2 replicates of 10 animals) were exposed to Water Accommodated Fractions (WAFs) of the test item over a range of nominal loading rates of 0.1, 0.28, 0.32, 0.56 and 1.0 mg/L for 48 hours at a temperature of 21 degrees C under static test conditions. The number of immobilized daphnids were recorded after 24 and 48 hours.

 

Results.The 48-Hour EL50 for the test item to Daphnia magna based on nominal loading rates was 0.75 mg/L with 95% confidence limits from 0.56 to 1.0 mg/L. The No Observed Effect Loading rate was 0.56 mg/L loading rate WAF. Total Organic Carbon analysis of the test preparations at 0 hours and at 48 hours confirmed that exposure to the test material occurred.

 

The dissolved test material may have been one or several components of the test material. Given that toxicity cannot be attributed to a single component or a mixture of components but to the test material as a whole, the results were based on nominal loading rates only.