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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2010-04-23 to 2010-04-29
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP study, according to the OECD 201 technical guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
no
GLP compliance:
yes
Analytical monitoring:
no
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Water accommodated fractions (WAF)* of 100 - 50 - 25 - 12.5 - 6.25 mg/L were prepared with dilution water one day prior to application. The WAF’s were shaken with 20 rpm for 24 h at room temperature. After a separation phase of 1 h the WAF’s were taken from the homogeneous liquid phase.
- Eluate: Dilution water
- Differential loading: The water accomodated fractions (WAF) were tested with a dilution factor 2: 6.25 - 12.5 - 25 - 50 and 100 mg/L
- Controls: Six replicates (without test item) were tested under the same test conditions as the test replicates.
Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Common name: Desmodesmus subspicatus Chodat
- Strain: SAG 86.81
- Source (laboratory, culture collection): SAG Pflanzenphysiologisches Institut der Universitaet Goettingen, Nikolausberger Weg 18, D-37073 Goettingen, Germany
- Age of inoculum (at test initiation): 3 days
- Method of cultivation: Fresh stocks were prepared from Z-Agar. Light intensity amounted 35 - 70 µE x m-2 x s-1 for 24 h per day.


ACCLIMATION
- Culturing media and conditions (same as test or not): Same as test
- Any deformed or abnormal cells observed: No
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Post exposure observation period:
No
Hardness:
Not measured
Test temperature:
Mean: 21.5 °C, Min: 21 °C, Max: 22 °C
pH:
Water accommodated fraction pH-value
[mg/L] Start; 0 h End; 72 h
100 10.7 7.75
50.0 10.1 7.83
25.0 9.48 7.85
12.5 8.98 7.86
6.25 8.86 7.73
100 (pH adjusted) 7.95 7.54
Control 8.22 8.23
Dissolved oxygen:
Not measured
Salinity:
Not measured, freshwater
Nominal and measured concentrations:
The water accomodated fractions (WAF) were tested with a dilution factor 2: 6.25 - 12.5 - 25 - 50 and 100 mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel: 250 mL Erlenmeyer flasks
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: sterile 250 mL Erlenmeyer flasks, test volume 100 mL
- Aeration: Test containers were placed on a rotary shaker and oscillated at appr. 70 rpm
- Type of flow-through (e.g. peristaltic or proportional diluter): None
- Renewal rate of test solution (frequency/flow rate): One application at test start
- Initial cells density: 5074 cells/mL
- Control end cells density: Mean 681856 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6
- No. of vessels per vehicle control (replicates): None


GROWTH MEDIUM
- Standard medium used: yes



TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Dilution water, composition acc. to the guideline
- Hardness: 0.24 mmol Ca+Mg/L
- pH-value: 8.1 +/- 0.2
- Culture medium: Nutrient Medium Z acc. to LÜTTGE et al. (1994)


OTHER TEST CONDITIONS
- Sterile test conditions: no
- Adjustment of pH: no
- Photoperiod: 24 h
- Light intensity and quality: 60 - 120 µE x m-2 x s-1



EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: [counting chamber; electronic particle counter; fluorimeter; spectrophotometer; colorimeter] Fluorimeter, via Chlorophyll-a fluorescence (excitation at 436 nm, emission at 685 nm), cell concentrations were related to all cell density values acc. to a calibration curve.



TEST CONCENTRATIONS
- Range finding study: Yes
Results of the Range Finding Test (0-72 h)

Nominal Loading Level
[mg/L] Specific Growth Rate Inhibition [%] Yield Inhibition [%]
100 18 56
10 - 1 - 6
1 - 1 - 5
100 (pH adjusted) 23 67







Reference substance (positive control):
yes
Remarks:
Potassium dichromate
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
22.4 mg/L
Nominal / measured:
nominal
Conc. based on:
other: nominal loading level of the water accommodated fraction
Basis for effect:
growth rate
Remarks on result:
other: (21.4 - 23.6)
Details on results:
- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test):
- Unusual cell shape: No
- Colour differences: No
- Flocculation: No
- Adherence to test vessels: No
- Aggregation of algal cells: No
- Other: No
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: No
- Effect concentrations exceeding solubility of substance in test medium: Yes
Results with reference substance (positive control):
- Results with reference substance valid? Yes
- EC50:
Rate-related inhibition: 0.614 (CI 0.551 - 0.679) mg/L
Yield Inhibition: 0.333 (CI 0.318 - 0.350) mg/L
Reported statistics and error estimates:
NOEL/LOEL was determined by calculation of statistical significance of growth rates and yield. One Way Analysis of Variance (ANOVA) and DUNNETT’s test was used for NOEL/LOEL calculations. When running a One Way Analysis of Variance a Normality test and an Equal Variance test were done first. P-values for both Normality and Equal Variance test are 0.05. The a-value (acceptable probability of incorrectly concluding that there is a difference) was =0.05. Equal Variance test failed for growth rates. Transformation of the growth rates (y = y squared) was carried out.
Detection of statistically significant differences were considered negligible when inhibition values were ≤ 10 %. These findings were marked “biologically not significant”.
EL10-, EL20- and EL50-values of the growth rate and yield inhibition after 72 h were calculated by sigmoidal dose-response regression. Calculation of the confidence intervals EL10-, EL20- and EL50-values were carried out using standard procedures.

NOEL, LOEL, EL - values and 95 % Confidence Intervals of Flue Dust S (0-72 h)

                   based on nominal loading level of the water accommodated fraction [mg/L]

                               

Rate-related Inhibition

NOEL

6.25

LOEL

12.5

ErL101)

9.95 ( 6.25 – 11.4)

ErL201)

14.3 (13.2 – 15.4)

ErL501)

22.4 (21.4 – 23.6)

Inhibition of Yield

NOEL

6.25

LOEL

6.25

EyL101)

6.25

EyL201)

6.25

EyL501)

12.2 (11.4 – 12.9)

Cell Densities

 

Water accommodated fraction

Replicate

Cell density [cells/mL]

[mg/L]

No.

0 h

24 h

48 h

72 h

 

100

1

5074

18702

52035

131826

 

2

5074

17563

60645

145339

 

3

5074

17231

51027

131276

 

Mean

5074

17832

54569

136147

 

  50.0

1

5074

16226

12897

18940

 

2

5074

16689

14693

18522

 

3

5074

19330

16714

21007

 

Mean

5074

17415

14768

19490

 

  25.0

1

5074

20584

19629

40687

 

2

5074

20699

22704

37263

 

3

5074

19399

22105

50682

 

Mean

5074

20227

21479

42877

 

  12.5

1

5074

25890

98525

365222

 

2

5074

22196

72757

296990

 

3

5074

22126

95873

324870

 

Mean

5074

23404

89052

329027

 

    6.25

1

5074

24086

104782

449576

 

2

5074

25336

98226

482605

 

3

5074

24012

132067

505692

 

Mean

5074

24478

111692

479291

 

100                                        (pH adjusted)

1

5074

20711

24672

70219

 

2

5074

19248

29416

83614

 

3

5074

20429

36771

108185

 

Mean

5074

20129

30286

87339

 

Control

1

5074

24410

144261

727314

 

2

5074

20986

109173

624002

 

3

5074

23700

118496

693152

 

4

5074

21851

112248

704579

 

5

5074

20502

111153

630287

 

6

5074

26066

137951

711803

 

Mean

5074

22919

122214

681856

 

Evaluation after 72 h

                   Statistically significant differences of growth rates and yield compared to

                   control values are marked (+), not significant differences are marked (-).

Water accommodated fraction

Replicate

Growth rate

Rate-related inhibition

Yield

Inhibition of yield

[mg/L]

No.

[d-1]

[%]

[cells/mL]

[%]

100

1

1.09

33.5

126752

81.3

2

1.12

31.5

140265

79.3

3

1.08

33.6

126202

81.4

Mean

(+)

1.10

32.9

(+)

131073

80.6

  50.0

1

0.439

73.1

13866

98.0

2

0.432

73.6

13448

98.0

3

0.474

71.0

15933

97.7

Mean

(+)

0.448

72.6

(+)

14416

97.9

  25.0

1

0.694

57.5

35613

94.7

2

0.665

59.3

32189

95.2

3

0.767

53.0

45608

93.3

Mean

(+)

0.709

56.6

(+)

37803

94.4

  12.5

1

1.43

12.7

360148

46.8

2

1.36

16.9

291916

56.9

3

1.39

15.1

319796

52.8

Mean

(+)

1.39

14.9

(+)

323953

52.1

    6.25

1

1.50

  8.47

444502

34.3

2

1.52

  7.02

477531

29.4

3

1.53

  6.07

500618

26.0

Mean

(+)*

1.52

  7.19

(+)

474217

29.9

100                              (pH adjusted)

1

0.876

46.4

65145

90.4

2

0.934

42.8

78540

88.4

3

1.02

37.5

103111

84.8

Mean

(+)

0.943

42.2

(+)

82265

87.8

Control

1

1.66

722240

2

1.60

618928

3

1.64

688078

4

1.64

699505

5

1.61

625213

6

1.65

706729

Mean

1.63

676782

Section-by-Section and Average Specific Growth Rates of the Control Group
                   (0 – 72 h)

Replicate No.

Specific growth rate [d-1]

Mean

(0 - 72 h)

SD

±

CV
[%]

Mean CV [%]

section-by-section                           

0 - 24 h

24 - 48 h

48 - 72 h

Control

1

1.57

1.78

1.62

1.66

0.108

6.52

7.97

2

1.42

1.65

1.74

1.60

0.166

10.4

3

1.54

1.61

1.77

1.64

0.115

7.04

4

1.46

1.64

1.84

1.64

0.189

11.5

5

1.40

1.69

1.74

1.61

0.184

11.5

6

1.64

1.67

1.64

1.65

0.016

0.975

Mean

1.63

 

SD ±

0.02

 

CV [%]

1.33

 
Validity criteria fulfilled:
yes
Conclusions:
In this study Flue Dust S was found to inhibit the growth of the freshwater green alga Desmodesmus subspicatus after 72 h. The NOEL-values for inhibition of specific growth rate and inhibition of yield after 72 h were 6.25 mg/L and < 6.25 mg/L, respectively. The LOEL-values for inhibition of specific growth rate and inhibition of yield after 72 h were 12.5 mg/L and 6.25 mg/L, respectively. The EL50-values for inhibition of specific growth rate (ErC50) and yield (EyC50) after 72 h were 22.4 (21.4 – 23.6) and 12.2 (11.4 – 12.9) mg/L, respectively.
All effect values are given based on nominal loading levels of the water accommodated fractions.
Executive summary:

The toxicity of Flue Dust S (batch number not specified) to the unicellular freshwater green alga Desmodesmus subspicatus was determined according to the principles of OECD 201 at Dr.U.Noack-Laboratorienin 31157 Sarstedt, Germany from April 23 to 29, 2010 with the definitive exposure phase being conducted from April 26 to 29, 2010. The aim of the study was to assess the effects on growth rate and yield over a period of 72 h.

The study was conducted under static conditions with an initial cell density of approximately  2 – 5 x 103cells/mL. Based on a preliminary test, a definitive test with the water accommodated fractions (WAF’s*) were carried out in a geometrical series with a dilution factor of 2, nominal: 6.25 - 12.5 - 25 - 50 - 100 mg/L. Additionally the highest loading level of 100 mg/L was tested by correction of the pH-value in order to check for possible toxic effects due to the pH-value. The preparation method has been chosen with regard to the test item properties and in accordance with the relevant OECD guidance document (2000). Three replicates were tested for each test item loading and six replicates for the control. Environmental conditions were determined to be within the acceptable limits.

Per definition of the WAF all terms related to the concentration were given as loading level because partly dissolved compounds and mixtures cannot be related to concentrations.

Table 1:    NOEL, LOEL, EL - values and 95 % Confidence Intervals of Flue Dust S(0-72 h)

                   based on nominal loading level of the water accommodated fraction [mg/L]

                               

Rate-related Inhibition

NOEL

6.25

LOEL

12.5

ErL101)

9.95 ( 6.25 – 11.4)

ErL201)

14.3 (13.2 – 15.4)

ErL501)

22.4 (21.4 – 23.6)

Inhibition of Yield

NOEL

6.25

LOEL

6.25

EyL101)

6.25

EyL201)

6.25

EyL501)

12.2 (11.4 – 12.9)

1) Values of the loading level 100 mg/L were excluded for calculation

Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2010-04-23 to 2010-04-29
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP study, according to the OECD 201 technical guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
no
GLP compliance:
yes
Analytical monitoring:
no
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Water accommodated fractions (WAF)* of 100 - 50 - 25 - 12.5 - 6.25 mg/L were prepared with dilution water one day prior to application. The WAF’s were shaken with 20 rpm for 24 h at room temperature. After a separation phase of at least 1 h the WAF’s were taken from the homogeneous liquid phase.
- Eluate: Dilution water
- Differential loading: The water accomodated fractions (WAF) were tested with a dilution factor 2: 6.25 - 12.5 - 25 - 50 and 100 mg/L
- Controls: Six replicates (without test item) were tested under the same test conditions as the test replicates.
Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Common name: Desmodesmus subspicatus Chodat
- Strain: SAG 86.81
- Source (laboratory, culture collection): SAG Pflanzenphysiologisches Institut der Universitaet Goettingen, Nikolausberger Weg 18, D-37073 Goettingen, Germany
- Age of inoculum (at test initiation): 3 days
- Method of cultivation: Fresh stocks were prepared from Z-Agar. Light intensity amounted 35 - 70 µE x m-2 x s-1 for 24 h per day.


ACCLIMATION
- Culturing media and conditions (same as test or not): Same as test
- Any deformed or abnormal cells observed: No
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Post exposure observation period:
No
Hardness:
Not measured
Test temperature:
Mean: 21.5 °C, Min: 21 °C, Max: 22 °C
pH:
Water accommodated fraction pH-value
[mg/L] Start; 0 h End; 72 h
100 10.7 7.83
50.0 10.0 7.84
25.0 9.40 7.82
12.5 9.02 7.78
6.25 8.62 7.73
100 (pH adjusted) 7.88 7.42
Control 8.22 8.23
Dissolved oxygen:
Not measured
Salinity:
Not measured, freshwater
Nominal and measured concentrations:
The water accomodated fractions (WAF) were tested with a dilution factor 2: 6.25 - 12.5 - 25 - 50 and 100 mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel: 250 mL Erlenmeyer flasks
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: sterile 250 mL Erlenmeyer flasks, test volume 100 mL
- Aeration: Test containers were placed on a rotary shaker and oscillated at appr. 70 rpm
- Type of flow-through (e.g. peristaltic or proportional diluter): None
- Renewal rate of test solution (frequency/flow rate): One application at test start
- Initial cells density: 5074 cells/mL
- Control end cells density: Mean 681856 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6
- No. of vessels per vehicle control (replicates): None


GROWTH MEDIUM
- Standard medium used: yes



TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Dilution water, composition acc. to the guideline
- Hardness: 0.24 mmol Ca+Mg/L
- pH-value: 8.1 +/- 0.2
- Culture medium: Nutrient Medium Z acc. to LÜTTGE et al. (1994)


OTHER TEST CONDITIONS
- Sterile test conditions: no
- Adjustment of pH: no
- Photoperiod: 24 h
- Light intensity and quality: 60 - 120 µE x m-2 x s-1



EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: [counting chamber; electronic particle counter; fluorimeter; spectrophotometer; colorimeter] Fluorimeter, via Chlorophyll-a fluorescence (excitation at 436 nm, emission at 685 nm), cell concentrations were related to all cell density values acc. to a calibration curve.



TEST CONCENTRATIONS
- Range finding study: Yes
Results of the Range Finding Test (0-72 h)
Results of the Range Finding Test (0-72 h)

Nominal Loading Level
[mg/L] Specific Growth Rate Inhibition [%] Yield Inhibition [%]
100 67 96
10 - 2 - 11
1 6 26
100 (pH adjusted) 14 48








Reference substance (positive control):
yes
Remarks:
Potassium dichromate
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
28.2 mg/L
Nominal / measured:
nominal
Conc. based on:
other: nominal loading level of the water accommodated fraction
Basis for effect:
growth rate
Remarks on result:
other: (23.9 - 34.0)
Details on results:
- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test):
- Unusual cell shape: No
- Colour differences: No
- Flocculation: No
- Adherence to test vessels: No
- Aggregation of algal cells: No
- Other: No
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: No
- Effect concentrations exceeding solubility of substance in test medium: Yes
Results with reference substance (positive control):
- Results with reference substance valid? Yes
- EC50:
Rate-related inhibition: 0.614 (CI 0.551 - 0.679) mg/L
Yield Inhibition: 0.333 (CI 0.318 - 0.350) mg/L
Reported statistics and error estimates:
NOEL/LOEL was determined by calculation of statistical significance of growth rates and yield. One Way Analysis of Variance (ANOVA) and DUNNETT’s test was used for NOEL/LOEL calculations. When running a One Way Analysis of Variance a Normality test and an Equal Variance test were done first. P-values for both Normality and Equal Variance test are 0.05. The a-value (acceptable probability of incorrectly concluding that there is a difference) was =0.05. Equal Variance test failed for growth rates. Transformation of the growth rates (y = y squared) was carried out.
Detection of statistically significant differences were considered negligible when inhibition values were ≤ 10 %. These findings were marked “biologically not significant”.
EL10-, EL20- and EL50-values of the growth rate and yield inhibition after 72 h were calculated by sigmoidal dose-response regression. Calculation of the confidence intervals EL10-, EL20- and EL50-values were carried out using standard procedures.

NOEL, LOEL, EL - values and 95 % Confidence Intervals of Flue Dust T (0-72 h)

                   based on nominal loading level of the water accommodated fraction [mg/L]

                               

Rate-related Inhibition

NOEL

6.25

LOEL

12.5

ErL10

10.3 (8.33 – 12.5)

ErL20

13.7 (11.6 – 15.9)

ErL50

28.2 (23.9 – 34.0)

Inhibition of Yield

NOEL

6.25

LOEL

12.5

EyL10

7.06 (6.65 – 7.68)

EyL20

7.87 (7.29 – 8.59)

EyL50

11.1 (10.1 – 11.8)

Cell Densities

 

Water accommodated fraction

Replicate

Cell density [cells/mL]

[mg/L]

No.

0 h

24 h

48 h

72 h

 

100

1

5074

17981

22261

29309

 

2

5074

21622

24631

32708

 

3

5074

20306

20174

28911

 

Mean

5074

19970

22355

30309

 

  50.0

1

5074

21417

17907

24615

 

2

5074

19297

15230

26542

 

3

5074

21380

17817

23151

 

Mean

5074

20698

16985

24769

 

  25.0

1

5074

20142

34865

73532

 

2

5074

19408

28924

64856

 

3

5074

24299

51064

123917

 

Mean

5074

21283

38284

87435

 

  12.5

1

5074

20966

69957

257921

 

2

5074

21974

53204

313984

 

3

5074

23221

89653

272546

 

Mean

5074

22054

70938

281484

 

    6.25

1

5074

22942

139956

677035

 

2

5074

23294

177323

668643

 

3

5074

25381

152982

720676

 

Mean

5074

23872

156754

688785

 

100                                        (pH adjusted)

1

5074

19338

39161

98464

 

2

5074

21458

34549

109825

 

3

5074

23487

30916

85824

 

Mean

5074

21428

34875

98038

 

Control

1

5074

24410

144261

727314

 

2

5074

20986

109173

624002

 

3

5074

23700

118496

693152

 

4

5074

21851

112248

704579

 

5

5074

20502

111153

630287

 

6

5074

26066

137951

711803

 

Mean

5074

22919

122214

681856

 

Evaluation after 72 h

                   Statistically significant differences of growth rates and yield compared to

                   control values are marked (+), not significant differences are marked (-).

Water accommodated fraction

Replicate

Growth rate

Rate-related inhibition

Yield

Inhibition of yield

[mg/L]

No.

[d-1]

[%]

[cells/mL]

[%]

100

1

0.585

64.2

24235

96.4

2

0.621

62.0

27634

95.9

3

0.580

64.5

23837

96.5

Mean

(+)

0.595

63.6

(+)

25235

96.3

  50.0

1

0.526

67.8

19541

97.1

2

0.552

66.2

21468

96.8

3

0.506

69.0

18077

97.3

Mean

(+)

0.528

67.7

(+)

19695

97.1

  25.0

1

0.891

45.4

68458

89.9

2

0.849

48.0

59782

91.2

3

1.07

34.8

118843

82.4

Mean

(+)

0.935

42.7

(+)

82361

87.8

  12.5

1

1.31

19.8

252847

62.6

2

1.38

15.8

308910

54.4

3

1.33

18.7

267472

60.5

Mean

(+)

1.34

18.1

(+)

276410

59.2

    6.25

1

1.63

  0.11

671961

  0.71

2

1.63

  0.36

663569

  1.95

3

1.65

 -1.17

715602

 -5.74

Mean

(-)

1.64

 -0.23

(-)

683711

 -1.03

100                              (pH adjusted)

1

0.989

39.5

93390

86.2

2

1.03

37.2

104751

84.5

3

0.943

42.3

80750

88.1

Mean

(+)

0.985

39.7

(+)

92964

86.3

Control

1

1.66

722240

2

1.60

618928

3

1.64

688078

4

1.64

699505

5

1.61

625213

6

1.65

706729

Mean

1.63

676782

Section-by-Section and Average Specific Growth Rates of the Control Group
                   (0 – 72 h)

Replicate No.

Specific growth rate [d-1]

Mean

(0 - 72 h)

SD

±

CV
[%]

Mean CV [%]

section-by-section                           

0 - 24 h

24 - 48 h

48 - 72 h

Control

1

1.57

1.78

1.62

1.66

0.108

6.52

7.97

2

1.42

1.65

1.74

1.60

0.166

10.4

3

1.54

1.61

1.77

1.64

0.115

7.04

4

1.46

1.64

1.84

1.64

0.189

11.5

5

1.40

1.69

1.74

1.61

0.184

11.5

6

1.64

1.67

1.64

1.65

0.016

0.975

Mean

1.63

 

SD ±

0.02

 

CV [%]

1.33

 
Validity criteria fulfilled:
yes
Conclusions:
In this study Flue Dust T was found to inhibit the growth of the freshwater green alga Desmodesmus subspicatus after 72 h. The NOEL-values for inhibition of specific growth rate and inhibition of yield after 72 h were 6.25 mg/L. The LOEL-values for inhibition of specific growth rate and inhibition of yield after 72 h were 12.5 mg/L. The EL50-values for inhibition of specific growth rate (ErC50) and yield (EyC50) after 72 h were 28.2 (23.9 – 34.0) and 11.1 (10.1 – 11.8) mg/L, respectively.
All effect values are given based on nominal loading levels of the water accommodated fractions.
Executive summary:

The toxicity of Flue Dust T (batch number 12-2009)to the unicellular freshwater green alga Desmodesmus subspicatus was determined according to the principles of OECD 201 at Dr.U.Noack-Laboratorien in 31157 Sarstedt, Germany from April 23 to 29, 2010 with the definitive exposure phase being conducted from April 26 to 29, 2010. The aim of the study was to assess the effects on growth rate and yield over a period of 72 h.

The study was conducted under static conditions with an initial cell density of approximately  2 – 5 x 103cells/mL. Based on a preliminary test, a definitive test with the water accommodated fractions (WAF’s*) were carried out in a geometrical series with a dilution factor of 2, nominal: 6.25 - 12.5 - 25 - 50 - 100 mg/L. The preparation method has been chosen with regard to the test item properties and in accordance with the relevant OECD guidance document (2000). Three replicates were tested for each test item loading and six replicates for the control. Environmental conditions were determined to be within the acceptable limits.

Per definition of the WAF all terms related to the concentration were given as loading level because partly dissolved compounds and mixtures cannot be related to concentrations.

NOEL, LOEL, EL - values and 95 % Confidence Intervals of Flue Dust T (0-72 h)

                   based on nominal loading level of the water accommodated fraction [mg/L]

                               

Rate-related Inhibition

NOEL

6.25

LOEL

12.5

ErL10

10.3 (8.33 – 12.5)

ErL20

13.7 (11.6 – 15.9)

ErL50

28.2 (23.9 – 34.0)

Inhibition of Yield

NOEL

6.25

LOEL

12.5

EyL10

7.06 (6.65 – 7.68)

EyL20

7.87 (7.29 – 8.59)

EyL50

11.1 (10.1 – 11.8)

Description of key information

No acute toxicity to aquatic algae due to a Klimisch 1 study result.

Key value for chemical safety assessment

EC50 for freshwater algae:
28.2 mg/L
EC10 or NOEC for freshwater algae:
10.3 mg/L

Additional information

Short-term toxicity testing with the freshwater green alga Desmodesmus subspicatus was carried out according to the OECD 201 guidance taking into account GLP and thus resulting in a Klimish 1 score.
In two studies the two samples Flue Dust T and Flue Dust S were found to inhibit the growth of the freshwater green alga Desmodesmus subspicatus after 72 h. The NOEL-values for inhibition of specific growth rate and inhibition of yield after 72 h were 6.25 mg/L. The LOEL-values for inhibition of specific growth rate and inhibition of yield after 72 h were 12.5 mg/L. The EL50-values for inhibition of specific growth rate (ErC50) and yield (EyC50) after 72 h were 28.2 and 11.1 mg/L (for Flue Dust T), and 22.4 and 12.2 mg/L (for Flue Dust S), respectively. All effect values are given based on nominal loading levels of the water accommodated fractions.