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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 Jul - 09 Oct 2008
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2009
Report Date:
2009

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Qualifier:
according to
Guideline:
EU Method C.2 (Acute Toxicity for Daphnia)
Qualifier:
according to
Guideline:
EPA OPP 72-2 (Aquatic Invertebrate Acute Toxicity Test)
GLP compliance:
yes (incl. certificate)
Remarks:
Department of Health of the Government of the United Kingdom

Test material

Reference
Name:
Unnamed
Type:
Constituent

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations: control, 1.0, 1.8, 3.2, 5.6, 10, 18, 32, 56, 100 mg/L
- Sampling method: Water samples were taken from the control (replicates R1 – R2 pooled) and all test groups (replicates R1 – R2 pooled) at 0 (fresh media), 24 (old and fresh media) and 48 h (old media) for quantitative analysis.
- Sample storage conditions before analysis: Duplicate samples were taken and stored at approximately -20 °C for further analysis if necessary.

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: An amount of test material (200 mg) was dissolved in dechlorinated tap water with the aid of ultrasonication for approximately 30 min and the volume adjusted to 2 L to give the 100 mg/L test concentration. Aliquots (10, 18, 32, 56, 100, 180, 320 and 560 mL) of the 100 mg/L test concentration were each separately dispersed in a final volume of 1 L of dechlorinated tap water to give the 1.0, 1.8, 3.2, 5.6, 10, 18, 32 and 56 mg/L test concentrations, respectively. Each prepared concentration was inverted several times to ensure adequate mixing and homogeneity.
- Eluate: no
- Differential loading: no
- Controls: yes, test medium control

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: water flea
- Holding conditions: Adult Daphnia were maintained in polypropylene vessels containing approximately 2 L of reconstituted water in a temperature controlled room at approximately 20 °C. The lighting cycle was controlled to give a 16 hours light and 8 hours darkness cycle with 20 min dawn and dusk transition periods. Each culture was fed daily with a suspension of algae (Chlorella sp.). Culture conditions ensured that reproduction was by parthenogenesis. Gravid adults were isolated the day before initiation of the test, such that the young daphnids produced overnight were less than 24 h old. These young were removed from the cultures and used for testing. The diet and diluent water are considered not to contain any contaminant that would affect the integrity or outcome of the study.

Study design

Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h

Test conditions

Hardness:
160 mg/L as CaCO3
Test temperature:
21 - 22 °C
pH:
7.6 - 8.3
Dissolved oxygen:
96-100% air saturation value
Conductivity:
409 µS/cm
Nominal and measured concentrations:
nominal: control, 1.0, 1.8, 3.2, 5.6, 10, 18, 32, 56 and 100 mg/L
measured: < LOQ, 0.49, 0.94, 2.2, 3.8, 7.2, 13, 24, 43 and 66 mg/L (time-weighted average)
Details on test conditions:
TEST SYSTEM
- Type: covered to reduce evaporation
- Material, size, headspace, fill volume: glass, 250 mL, fill volume: 200 mL, headspace: 50 mL
- Aeration: no
- Renewal rate of test solution (frequency/flow rate): every 24 h
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: dechlorinated tap water
- Total organic carbon: 1.041 mg/L (mean)
- Particulate matter: 0.1 mg/L
- Chlorine: 0.297 mg/L (mean)
- Conductivity: 421.385 µS/cm at 20 °C
- Culture medium different from test medium: no
- Intervals of water quality measurement: regularly

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h light / 8 h darkness (20 min transition period)
- Feeding: none

EFFECT PARAMETERS MEASURED
- Immobilisation was recorded after 3, 24 and 48 h

RANGE-FINDING STUDY
- Test concentrations: control, 0.10, 1.0, 10, and 100 mg/L
- Results used to determine the conditions for the definitive study: No immobilisation was observed at the test concentrations of 0.10 and 1.0 mg/L. However, immobilisation was observed at 10 and 100 mg/L.
Reference substance (positive control):
yes
Remarks:
potassium dichromate

Results and discussion

Effect concentrationsopen allclose all
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
10 mg/L
Nominal / measured:
meas. (TWA)
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: 95% CI: 8.8-12 mg/L
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
3.8 mg/L
Nominal / measured:
meas. (TWA)
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
14 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: 95% CI: 12-17 mg/L
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
5.6 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
- Mortality of control: 0%
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: No, the test preparations were observed to be clear colourless solutions
Results with reference substance (positive control):
The results from the positive control with potassium dichromate were within the normal range for this reference material. The mean EC50 (48 h) value calculated from all positive controls was 0.78 mg/L (SD = 0.22).
Reported statistics and error estimates:
The EC50 values and associated confidence limits at 24 and 48 h and the slope of the response curve and its standard error were calculated by the maximum-likelihood probit method (Finney 1971) using the ToxCalc computer software package (ToxCalc 1999). Probit analysis is used where two or more partial responses to exposure are shown.

Any other information on results incl. tables

Table 1: Immobilisation after 24 and 48 h

Nominal concentration [mg/L]

Cumulative Immobilised Daphnia

24 h

48 h

R1

R2

Total

%

R1

R2

Total

%

Control

0

0

0

0

0

0

0

0

1.0

0

0

0

0

0

0

0

0

1.8

0

0

0

0

0

0

0

0

3.2

0

0

0

0

0

0

0

0

5.6

0

0

0

0

0

0

0

0

10

0

2

2

10

1

2

3

15

18

4

4

8

40

9

6

15

75

32

10

10

20

100

10

10

20

100

56

10

10

20

100

10

10

20

100

100

10

10

20

100

10

10

20

100

Table 2: Measured concentration of the test item during exposure

 

0 h fresh [mg/L]

% of nominal

24 h old [mg/L]

% of nominal

24 h fresh [mg/L]

% of nominal

48 h old [mg/L]

% of nominal

Control

< LOQ

-

< LOQ

-

< LOQ

-

< LOQ

-

1.0

0.916

92

0.592

59

0.812

81

< LOQ

-

1.8

1.57

87

1.13

63

1.49

82

0.12

7

3.2

2.94

92

2.13

66

2.63

82

1.23

38

5.6

5.15

92

3.49

62

4.61

82

2.33

42

10

9.33

92

6.81

68

8.63

86

4.70

47

18

16.6

92

12.5

69

15.3

85

9.58

53

32

30.0

94

22.4

70

27.5

86

18.4

57

56

51.9

93

39.1

70

48.5

87

34.3

61

100

94.5

95

76.2

76

87.1

87

22.4

22

Table 3: Measured concentration of benzoic acid (hydrolysis product) during exposure

 

0 h fresh [mg/L]

24 h old [mg/L]

24 h fresh [mg/L]

48 h old [mg/L]

Control

< LOQ

< LOQ

< LOQ

< LOQ

1.0

< LOQ

< LOQ

< LOQ

< LOQ

1.8

< LOQ

< LOQ

0.0625

0.0565

3.2

0.0563

< LOQ

0.0835

< LOQ

5.6

0.0973

0.0607

0.127

< LOQ

10

0.112

0.0651

0.217

< LOQ

18

0.230

0.0692

0.338

< LOQ

32

0.489

0.142

0.595

< LOQ

56

1.25

0.364

1.25

< LOQ

100

1.99

0.681

2.07

< LOQ

Applicant's summary and conclusion

Validity criteria fulfilled:
yes