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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:
28 February 2011 - 02 March 2011
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: This study has been performed according to OECD and/or EC guidelines and according to GLP principles.

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:
ISO 6341 (Water quality - Determination of the Inhibition of the Mobility of Daphnia magna Straus (Cladocera, Crustacea))
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.2 (Acute Toxicity for Daphnia)
Deviations:
no
Qualifier:
according to
Guideline:
other: Guidance document on aquatic toxicity testing of difficult substances and mixtures, OECD series on testing and assessment number 23, December 14, 2000.
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Description: Yellow-brown powder
Batch: 00120R

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
Samples for possible analysis were taken from all test concentrations and the control according to the schedule below. In addition, the filter was retained for possible analysis of the residue.

Frequency: at t=0 h and t=48 h
Volume: 2 ml from the approximate centre of the test vessels
Storage: Samples were stored in a freezer until analysis.

At the end of the exposure period, the replicates were pooled at each concentration before sampling.

Additionally, reserve samples of 2 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:
The batch of the substance tested was a yellow-brown powder. The test substance was not completely soluble in test medium at the loading rate initially prepared.

Preparation of the test solutions started with prepared individually loading rates of 1.0, 10 and
100 mg/l applying a 2-day period of magnetic stirring to achieve maximum dissolution in test medium. The obtained aqueous mixture was filtered through a 0.45 µm membrane filter (Whatman, rc 55) and the clear and colourless filtrates were used as test concentrations. The lowest test concentration was prepared by subsequent dilution of the filtrate prepared at the loading rate of 1.0 mg/l in test medium.

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
Species: Daphnia magna (Crustacea, Cladocera) (Straus, 1820), at least third generation, obtained by acyclical parthenogenesis under specified breeding conditions.
Source: In-house laboratory culture with a known history.
Reason for selection: This system has been selected as an internationally accepted invertebrate species.
Validity of batch: 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.
Characteristics: For the test selection of young daphnids with an age of < 24 hours, from parental daphnids of more than two weeks old.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
48 h
Post exposure observation period:
none

Test conditions

Hardness:
180 mg/l expressed as CaCO3
Test temperature:
The temperature of the test medium was 20.8 °C at the start of the test. The temperature continuously measured in a temperature control vessel varied between 19.3 and 20.1°C during the test, and complied with the requirements as laid down in the protocol (18-22°C, constant within 2°C).
pH:
7.6-8.0
Dissolved oxygen:
9.4-9.8
Nominal and measured concentrations:
See table below in materials and methods. The measured concentration in the sample taken from the highest test concentration at the start of the test was 18 mg/l. During the exposure period the measured concentration remained constant (97% of initial). Based on these results the effect parameters were expressed in terms of the initially measured concentrations.
Details on test conditions:
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: glass, 100 ml, normal headspace, 80 ml
- Aeration: no
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4 for the highest concentration and 2 for the lower concentrations
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Adjusted ISO medium: the following chemicals (analytical grade) are dissolved in tap water purified by Reverse Osmosis (RO-water, GEON Waterbehandeling, Berkel-Enschot, The Netherlands):
Macro salts:
CaCl2.2H2O : 211.5 mg/l
MgSO4.7H2O: 88.8 mg/l
NaHCO3 : 46.7 mg/l
KCl : 4.2 mg/l
The hardness: 180 mg/l expressed as CaCO3 and the pH: 7.7 ± 0.3 after aeration.
- Culture medium different from test medium: yes, for culturing M7 medium is used
OTHER TEST CONDITIONS

- Adjustment of pH: no
- Photoperiod: 16 hours photoperiod daily
EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : EC50 t=24, 48 h and NOEC
TEST CONCENTRATIONS

- Spacing factor for test concentrations: 10
- Test concentrations:control and 0.45 µm filtered solutions prepared at loading rates of 1.0, 10 and 100 mg/l. In addition a ten-fold dilution of the filtrate prepared at a loading rate of 1.0 mg/l
Reference substance (positive control):
yes
Remarks:
potassium dichromate

Results and discussion

Effect concentrationsopen allclose all
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
18 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: .
Duration:
24 h
Dose descriptor:
EC50
Effect conc.:
> 18 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: .
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 18 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: .
Details on results:
No immobility was observed at any concentration tested.
Results with reference substance (positive control):
The 24h-EC50 was 0.77 mg/l with a 95% confidence interval between 0.72 and 0.86 mg/l.
The 48h-EC50 was 0.57 mg/l with a 95% confidence interval between 0.52 and 0.66 mg/l.
Reported statistics and error estimates:
No EC50 could be calculated because the test substance proved to be non-toxic (EC50 > maximum soluble concentration tested).

Any other information on results incl. tables

Acute immobilisation of daphnids after 24 and 48 hours

Test substance

Filtrate prep.

at (mg/l)

Vessel

number

 

Number

Daphnia

exposed

Response at 24 h

Response at 48 h

 

number

Total

%

 

number

Total

%

control

 A

 B

C

D

5

5

5

5

0

0

0

0

0

0

0

0

0

0

 

10% of 1.0

 A

 B

5

5

0

0

0

0

0

0

1.0

 

 A

 B

5

5

0

0

0

0

0

0

10

 A

 B

5

5

0

0

0

0

0

0

100 (18)

 A

 B

C

D

5

5

5

5

0

0

0

0

0

0

0

0

0

0

( ) between brackets: Initial concentration

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The test substance did not induce acute immobilisation of Daphnia magna at 17.8 mg/l after 48 hours of exposure (NOEC).
The 48h-EC50 was beyond the range tested, i.e. exceeded an initially measured concentration of 18 mg/l.
Due to low solubility of the test substance the concentrations that might be toxic to Daphnia magna could not be reached.