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Short-term toxicity to aquatic invertebrates

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Reference
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2016-04-27 - 2016-07-11 (experimental phase)
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Version / remarks:
version dated 13-Apr-2004
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Remarks:
Hess. Ministerium für Umwelt, Energie, Landwirtschaft und Verbraucherschutz, Mainzer Straße 80, D65189 Wiesbaden
Analytical monitoring:
yes
Details on sampling:
- Concentrations: 5, 12.5, 31.3, 78.1, 195.3 mg/L
- Sample storage conditions before analysis: The supporting analyses could not be performed on the same day of collection of the specimens. Therefore, these specimens from freshly prepared test solutions were stored deep-frozen, thawed over-night and then analysed.
Vehicle:
no
Remarks:
medium was used
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The test item was weighed in ELENDT M4 dilution water whilst stirring on a magnetic stirrer or shaking on a shaking machine at room temperature.
- Controls: medium without any test item
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): none stated
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: water flea
- Strain/clone: Daphnia magna STRAUS (clone 5)
- Source: obtained from Dr. M. Bergtold, BASF, D-67117 Limburgerhof; the strain originally derived from the Institut National de Recherche Chimique Appliquee, France in 1978
- Feeding during test: no

ACCLIMATION
- Acclimation period: The cultivation of the daphnia is performed in a way that the animals are transferred in new test medium at an interval of 1 to 3 days followed by feeding.
- Type and amount of food: Desmodesmus subspicatus- and/or Chlorella-cells
- Health during acclimation (any mortality observed): none stated

METHOD FOR PREPARATION AND COLLECTION OF EARLY INSTARS OR OTHER LIFE STAGES:
Daphnias used for the test are not older than 24 hr. Therefore, in every case, daphnia are transferred into fresh medium one day before starting of the daphnia test in order to get daphnia for the test younger than 24 hr.
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Post exposure observation period:
none
Test temperature:
20 ± 1°C
pH:
7.80 - 9.45 during definitive main test (1st srceening: 7.32 - 8.89; 2nd screening 7.85 - 9.29; 1st main test: 7.76 - 9.47)
Dissolved oxygen:
8.0 - 8.5 mg O2/L during definitive main test (1st srceening: 7.0 - 8.9; 2nd screening 8.0 - 8.4; 1st main test: 8.2 - 8.4)
Nominal and measured concentrations:
Nominal: 0, 5, 12.5, 31.3, 78.1, 195.3 mg/L
Found (t0): n.d., 3.5, 10.2, 23.6, 65.5, 145.3 mg/L
Found after “procedural recovery” correction (t0): n.d., 4.7, 13.5, 31.2, 82.2, 182.4 mg/L
Found (t48h): n.d., 2.9, 9.4, 25.0, 64.7, 164.2 mg/L
Found after “procedural recovery” correction (t48h): n.d., 3.8, 12.4, 33.1, 81.2, 206.1 mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel: beaker
- Material, size, headspace, fill volume: 50mL, glass
- 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: Ultrapure water generating systems: Purelab Classic D1l; Ser.-No. 1470984-10 01

OTHER TEST CONDITIONS
- Photoperiod: 16 hr of light and 8 hr of darkness

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : immobility, daily

VEHICLE CONTROL PERFORMED: yes, medium only

RANGE-FINDING STUDY
- Test concentrations: 1, 10, 100 mg/L (1st screening), 10, 100, 500 mg/L (2nd screening)
Reference substance (positive control):
yes
Remarks:
To verify the sensitivity of the test system the effect of K2Cr2O7 towards different animals of this breed was tested prior to beginning of the test.
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
49.4 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
12.5 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
LOEC
Effect conc.:
31.3 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
EC10
Effect conc.:
23.8 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
other: EC20
Effect conc.:
30.6 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
24 h
Dose descriptor:
EC50
Effect conc.:
98.1 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
24 h
Dose descriptor:
NOEC
Effect conc.:
78.1 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
24 h
Dose descriptor:
LOEC
Effect conc.:
195.3 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
24 h
Dose descriptor:
EC10
Effect conc.:
82.1 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
24 h
Dose descriptor:
other: EC20
Effect conc.:
87.3 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
- Mortality of control: no immobilisation noted
- Other adverse effects control: none stated
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: none stated
- Effect concentrations exceeding solubility of substance in test medium: no
Results with reference substance (positive control):
- Results with reference substance valid? yes
- Limit test: no
- Dose-response test: yes
- ECx: EC50 (24 hr) = 0.9 mg/L
- Other: In order to verify the sensitivity of the test system towards toxic items the effect of potassium dichromate towards different animals of this breed was tested prior to beginning of the test. The value of the EC50 (24 hr) in this period of time was at 0.9 mg/L potassium dichromate. This value is in accordance with the recommendations of 0.6 to 2.1 mg/L K2Cr2O7 given in OECD Guideline 202 (Daphnia sp., Acute Immobilisation Test).

Results – Biological Part

 

1st Screening-Test

 

Nominal Concentration of the test item (mg/L)

Ratio immobilised

Daphnia [%]

pH-Value

 

O2-Content

[mg O2/L]

Temperature

[°C]

24hr

48hr

t0

48hr

t0

48hr

t0

48hr

Control (0)

0 [0/10]1)

0 [0/10]1)

8.54

8.07

8.7

8.2

20.7

20.6

1

 

0 [0/10]1)

0 [0/10]1)

8.79

8.52

8.6

8.2

20.9

20.7

10

 

70 [7/10]1)

100 [10/10]1)

8.55

8.08

8.4

7.8

20.5

20.5

100

 

0 [0/10]1)

100 [10/10]1)

8.89

7.32

8.9

7.0

20.2

20.6

 

1) Numbers in brackets give the absolute numbers of immobilised animals at each concentration.

 

2ndScreening-Test (enlarged Screening)

 

Nominal Concentration of the test item (mg/L)

Ratio immobilised

Daphnia [%]

pH-Value

 

O2-Content

[mg O2/L]

Temperature

[°C]

24hr

48hr

t0

48hr

t0

48hr

t0

48hr

Control (0)

0 [0/10]1)

0 [0/10]1)

9.26

7.87

8.4

8.2

20.7

20.0

10

 

0 [0/10]1)

0 [0/10]1)

9.29

7.85

8.2

8.0

20.2

20.0

100

 

20 [2/10]1)

50 [5/10]1) 2)

9.28

7.89

8.3

8.1

20.1

20.0

500

 

100 [10/10]1)

100 [10/10]1)

9.29

7.86

8.2

8.0

20.3

20.0

 

1) Numbers in brackets give the absolute numbers of immobilised animals at each concentration.2) Immobilized daphnia in the treatments with the test item were adhering at the surface.

 

Definitive Main Test

 

Nominal Concentration of the test item (mg/L)

Ratio immobilised

Daphnia [%]

pH-Value

 

O2-Content

[mg O2/L]

Temperature [°C]

24 hr

48 hr

t0

48 hr

t0

48 hr

t0

48 hr

Control (0)

0 [0/20]1)

0 [0/20]1)

9.42

7.97

8.4

8.1

19.8

19.9

5.0

 

0 [0/20]1)

0 [0/20]1)

9.43

7.96

8.5

8.0

20.0

19.9

12.5

 

0 [0/20]1)

0 [0/20]1)

9.43

7.89

8.4

8.0

20.1

19.9

31.3

 

0 [0/20]1)

25 [5/20]1)

9.43

7.91

8.4

8.2

20.1

20.0

78.1

 

5 [1/20]1)

75 [15/20]1)

9.45

7.79

8.4

8.0

20.1

20.0

195.3

 

100 [20/20]1)

100 [20/20]1)

9.44

7.80

8.4

8.1

20.1

20.0

 

1) Numbers in brackets give the absolute numbers of immobilised animals at each concentration.

 

Effective Concentrations on Basis of the Nominal Concentrations:

 

 

Basis: Nominal Concentrations [mg/L]

                 t24hr

                   t48hr

NOEC

78.1

12.5

LOEC

195.3

31.3

                       EC10

82.1

23.8

                       EC20

87.3

30.6

                       EC50

98.1

49.4

 

 

Results of the Analytical Part (GC-MS)

 

The results of the supporting analyses can be summarised as follows:

 

Sample Designation

mg 3-Methyl-thiazolidin-thion-2/L found

mg 3-Methyl-thiazolidin-thion-2/L found after “procedural recovery” correction

% Recovery

on Basis of t0

Control time t0

n.d.

-

-

5 mg/L time t0

3.5

4.7

-

12.5 mg/L time t0

10.2

13.5

-

31.3 mg/L time t0

23.6

31.2

-

78.1 mg/L time t0

65.5

82.2

-

195.3 mg/L time t0

145.3

182.4

-

Control time t48 hr

n.d.

-

-

5 mg/L time t48 hr

2.9

3.8

81.5

12.5 mg/L time t48 hr

9.4

12.4

91.8

31.3 mg/L time t48 hr

25.0

33.1

105.9

78.1 mg/L time t48 hr

64.7

81.2

98.8

195.3 mg/L time t48 hr

164.2

206.1

113.0

Spike 5 mg/L

(“procedural recovery”)

3.8

(5)

-

Spike 195.8 mg/L

(“procedural recovery”)

156.0

(195.8)

-

 

As a result of the supporting analyse it can be stated that the results of the biological part should be based on the nominal concentrations applied because the necessary stability of ≥ 80% could be shown.

Validity criteria fulfilled:
yes
Conclusions:
The study was performed according to OECD TG 202 without deviations, the results were so obtained via a scientifically reasonable method. Hence, there is no doubt that the obtained results are not reliable:
Under the conditions used for the test, there was a significant immobilisation of the daphnias at concentrations >12.5 mg/L (definitive main test).
As a conclusion of the analytical part of this study, it can be stated that the concentrations of the test item remained sufficiently stable during incubation. Based on this, the reported effect concentrations should refer to the nominal concentrations tested. The following EC-values were determined accordingly after 48 hours:
Mobility:
LOEC = 31.3 mg/L
NOEC = 12.5 mg/L
EC50 = 49.4 mg/L
Based on these results, the test item does not need to be classified as acute toxic to the aquatic environment. With regard to chronic toxicity, taking into account the facts that the test item is soluble in water and not readily biodegradable, the test item should be classified as aquatic chronic Cat. 3.
Executive summary:

3-Methyl-thiazolidin-thion-2 was tested for acute toxicity towards daphnia according to OECD-Test Guideline 202 (version dated 13-Apr-2004; GLP). In order to in­vestigate the influence of the test item towards the daphnias, the swimming behaviour of the animals was recorded. Under the conditions used for the test, there was a significant immobilisation of the daphnias at concentrations >12.5 mg/L (definitive main test). As a conclusion of the analytical part of this study, it can be stated that the concentrations of 3-Methyl-thiazolidin-thion-2 remained sufficiently stable during incubation of 48hr: After 48 hr recoveries of >80% of the initial t0-concentrations were measured in the treatments. Based on this, the reported effect concentrations should refer to nominal concentrations (geometric mean).The following EC-values (effective concentrations) were determined accordingly:

 

 

Basis: Nominal Concentrations [mg/L]

                 t24hr

                   t48hr

NOEC

78.1

12.5

LOEC

195.3

31.3

                       EC10

82.1

23.8

                       EC20

87.3

30.6

                       EC50

98.1

49.4

 

The test is considered valid as all conditions for validity were met.

Description of key information

Acute toxicity to aquatic invertebrates: EC50 (48h) = 49.4 mg/L, NOEC = 12.5 mg/L, LOEC = 31.3 mg/L, based on immobilisation, for Daphnia magna STRAUS (OECD 202, GLP, static)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Effect concentration:
49.4 mg/L

Additional information

Based on these results, the test item does not need to be classified as acute toxic to the aquatic environment. With regard to chronic toxicity, taking into account the fact that the test item not readily biodegradable, the test item should be classified as aquatic chronic Cat. 3 base on the acute aquatic toxicity data.