Registration Dossier

Ecotoxicological information

Short-term toxicity to aquatic invertebrates

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
27 October - 29 November 2015
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Reference:
Composition 0
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Version / remarks:
(2004)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.2 (Acute Toxicity for Daphnia)
Version / remarks:
(2008)
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
Test material information:
Composition 1
Analytical monitoring:
yes
Details on sampling:
Test concentrations were verified by chemical analysis. Water samples (3.0 mL) were taken from the approximate centre of the test vessels of the control and each exposure level at the start and end of both 24-h (renewal) periods. Samples were stored in the freezer until analysis.

At the end of each refreshment period, samples were taken from one replicate of each test concentration and the control.
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION
Preparation of test solutions started with a loading rate of 100 mg/L applying one day of magnetic stirring in a closed vessel in order to reach the maximum solubility of the test item in the test medium. The resulting aqueous mixture was left to stabilize for one hour whereafter the clear and colourless Saturated Solution (SS) was siphoned out and used as the highest test concentration. The lower test concentrations were prepared by subsequent dilutions of the saturated solution in test medium.
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Daphnia magna (Straus 1820)
- Source: in-house laboratory culture with a known history (at least third generation, obtained by acyclical parthenogenesis under specified breeding conditions)
- Age at study initiation: young daphnids with an age of < 24 hours, from parental daphnids of more than two weeks old
- Method of breeding: start of each batch with newborn daphnids, i.e. less than 3 days old, by placing about 250 of them into 5 litres of medium in an all-glass culture vessel. Renewal of the medium: after 7 days of cultivation half of the medium twice a week.
- Feeding during test: no


Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Test temperature:
19.3 - 19.9°C
pH:
7.8-8.1
Dissolved oxygen:
8.5 - 9.8 mg O2/L
test end: 8.5-8.7 mg O2/L
Nominal and measured concentrations:
Based on the results of the range-finding test (expected EC50 was between concentrations obtained in 10 and 100% of a saturated solution prepared at a loading rate of 100 mg/L) the following dilutions of the saturated solution prepared at a loading rate of 100 mg/L were assigned to the final test: 4.6, 10, 22, 46 and 100%
Measured test concentrations: see tables 1 and 2 in field 'Any other information on results'
Details on test conditions:
TEST SYSTEM
The tests were performed in closed airtight all-glass vessels (60 mL) completely filled up with test solutions.

* Range-finding test (static):
- Three test concentrations (1.0, 10 and 100% of SS (saturated solution) prepared at 100 mg/L) plus one control each in duplicate with 5 animals/test vessel (i.e. 10 animals/concentration).

* Final test (semi-static):
- Five test concentrations (4.6, 10, 22, 46 and 100% of SS (saturated solution) prepared at 100 mg/L plus one control each in 4-fold with 5 animals/test vessel (i.e. 20 animals/concentration).
- Loading rate: 12.5 mL test solution per organism
- Aeration: no
- Test vessels were maintained at 20 °C under a photoperiod of 16 hours light : 8 hours dark and without supplementary aeration or feeding during the 48 hour exposure period.
- The temperature was measured continuously and the pH and dissolved oxygen levels were recorded at the start and at the end of the study for all concentrations and the control.

TEST MEDIUM / WATER PARAMETERS
- Test medium: adjusted ISO
- Culture medium different from test medium: yes (M7)

OTHER TEST CONDITIONS
- Adjustment of pH: no

EFFECT PARAMETERS MEASURED: Immobility (including mortality) - Daphnia were considered to be immobilised if they were unable to swim for approximately 15 seconds after gentle agitation of the test vessel.
Reference substance (positive control):
yes
Remarks:
potassium dichromate (September 2015)
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
0.51 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: 95% CL 0.44 - 0.71 mg/L, the EC50 is based on the arithmetic mean of geomean measured concentrations in samples taken at the start (Ct=0), after 24 hours in old (Ct=24, old) and fresh medium (Ct=24, fresh) and at the end of the test (Ct=48)
Details on results:
* Range-finding test:
Samples taken from 1.0 and 100% of the SS were analysed. At the start of the test the actual concentrations were 0.057 and 5.6 mg/L, respectively. Both concentrations remained stable during the 48-hour test period (83-92% of initial at the end of the test).

* Final test:
Analysis of the samples taken at the start of the first renewal period showed measured concentrations of 0.21, 0.49, 1.1, 2.5 and 5.5 mg/L at 4.6, 10, 22, 46, and 100% of the SS, respectively. The 5.5 mg/L concentration decreased to 73% of initial at the end of the 24-hour renewal period, while all lower concentrations remained stable (82-89% of initial). Analysis of the samples taken at the start of the second renewal period showed similar measured concentrations, i.e. 0.22, 0.48, 1.1, 2.5 and 5.5 mg/L at 4.6, 10, 22, 46 and 100% of the SS, respectively. All test concentrations remained stable during the 24-hour renewal period (91-95% of initial). Given this result, the EC50 values were expressed in terms of the mean measured concentrations.

Individual pH, temperature and dissolved oxygen values remained within acceptable limits throughout the duration of the study.
Results with reference substance (positive control):
- Results with reference substance valid? yes
- 48-h EC50: 0.39 mg/L

Table 1: Concentrations of the test item in test medium - final test

Time of sampling
[hours]

Percentage of SS1
[%]

Analysed concentration
[mg/L]

Relative to
initial
[%]

 

 

 

 

0 (fresh)

0

n.d.

 

 

4.6

0.212

 

 

10

0.493

 

 

22

1.05

 

 

46

2.45

 

 

100

5.53

 

 

 

 

 

24 (old)

0

n.d.

n.a.

 

4.6

0.184

87

 

10

0.428

87

 

22

0.856

82

 

46

2.19

89

 

100

4.05

73

 

 

 

 

24 (fresh)

0

n.d.

 

 

4.6

0.222

 

 

10

0.478

 

 

22

1.06

 

 

46

2.50

 

 

100

5.49

 

 

 

 

 

48 (old)

0

n.d.

n.a.

 

4.6

0.210

95

 

10

0.434

91

 

22

1.00

94

 

46

2.27

91

 

100

5.16

94

 

 

 

 

1       Percentage of a Saturated Solution (SS) prepared at a loading rate of 100 mg/L.

n.d.    Not detected.

n.a.    Not applicable.        

Table 2: Mean measured concentrations

Pinyl Iso Butyraldehyde

% of the SS prepared at 100 mg/L

Measured concentration (mg/L)

Mean measured concentration (mg/L)

t=0h (fresh)

t=24h

(old)

t=24h (fresh)

t=48h (old)

4.6

0.21

0.18

0.22

0.21

0.21

10

0.49

0.43

0.48

0.43

0.46

22

1.1

0.86

1.1

1.0

0.99

46

2.5

2.2

2.5

2.3

2.3

100

5.5

4.1

5.5

5.2

5.0

Range-finding test (static; 0.1, 1.0, 10 and 100% of a SS prepared at 100 mg/L)

After 24 hours of exposure, 20 and 100% of the daphnids exposed to 10 and 100 % of the SS prepared at 100 mg/L, respectively, were immobilized. No immobility was observed at any of the lower test concentrations and the control during the exposure period. No changes in effect were observed at 48 hours of exposure. The expected EC50was between concentrations obtained in 10 and 100% of an SS prepared at a loading rate of 100 mg/L.

 

Final test

Table 3 shows the responses recorded during the final test. After 48 hours of exposure 100% of the daphnids exposed to the three highest test concentrations were immobilized whereas 35% immobility was reached in the 0.46 mg/L group. No immobility was observed at the lowest test concentration and the control.

Table 3: Cumulative immobilisation data for Daphnia magna exposed for 48 hours to the test substance

 

Time (h)

Replicate

 Pinyl Iso Butyraldehyde mean measured concentrations (mg/L)

Control

0.21

0.46

0.99

2.3

5.0

0

A

5

5

5

5

5

5

B

5

5

5

5

5

5

C

5

5

5

5

5

5

D

5

5

5

5

5

5

Total introduced

20

20

20

20

20

20

24

A

0

0

0

2

5

5 (5)

B

0

0

1

1

5

5 (5)

C

0

0

0

3

5

5 (5)

D

0

0

0

0

5

5 (5)

Total immobilised

0

0

1

6

20

20

Effect %

0

0

5

30

100

100

 

 

 

 

 

 

48

A

0

0

1

5

5

5

B

0

0

3

5

5

5 (1)

C

0

0

0

5

5

5

D

0

0

3

5 (5)

5

5

Total immobilised

0

0

7

20

20

20

Effect %

0

0

35

100

100

100

 A, B, C, D = replicate 1, 2, 3, 4

Validity criteria fulfilled:
yes
Remarks:
<10% immobilization in control group, O2 conc. at end is >=3 mg/L in control and test vessels
Conclusions:
The 48 h EC50 (immobilisation) value for Daphnia magna is 0.51 mg/L based on arithmic mean concentrations.
Executive summary:

A study was performed to assess the acute toxicity of the substance to Daphnia magna under semi-static conditions (renewal period: 24 hours). The study was conducted in accordance with OECD TG 202 and GLP principles. Groups of twenty daphnids (less than 24 hours old) were exposed for 48 hours to five concentrations of the substance dispersed in test water (4.6 - 100 % of a saturated solution prepared at a loading rate of 100 mg/L) and an untreated control. The incidence of immobilisation was recorded for each test and control group at 24 hours and at 48 hours. After 24 hours at 0.46; 0.99; 2.3 and 5.0 mg/l 5, 30, 100 and 100% immobility, respectively was seen. At 48 hours the immobilisation increased. At these concentrations the immobility was 35, 100, 100 and 100%, respectively. This results in the 48-h EC50 of 0 51 mg/L. All results are expressed in terms of arithmic mean measured concentrations. Measured concentrations ranged from 73 - 89 % of initial at the end of the first renewal period (t=0-24 hours) and 91 -95 % of initial at the end of the second renewal period (t=24-48 hours).

Description of key information

A study was performed to assess the acute toxicity of the substance to Daphnia magna under semi-static conditions (renewal period: 24 hours). The study was conducted in accordance with OECD TG 202 and GLP principles. Groups of twenty daphnids (less than 24 hours old) were exposed for 48 hours to five concentrations of the substance dispersed in test water (4.6 - 100 % of a saturated solution prepared at a loading rate of 100 mg/L) and an untreated control. The incidence of immobilisation was recorded for each test and control group at 24 hours and at 48 hours. After 24 hours at 0.46; 0.99; 2.3 and 5.0 mg/l 5, 30, 100 and 100% immobility, respectively was seen. At 48 hours the immobilisation increased. At these concentrations the immobility was 35, 100, 100 and 100%, respectively. This results in the 48-h EC50 of 0 51 mg/L. All results are expressed in terms of arithmic mean measured concentrations. Measured concentrations ranged from 73 - 89 % of initial at the end of the first renewal period (t=0-24 hours) and 91 -95 % of initial at the end of the second renewal period (t=24-48 hours).

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
0.51 mg/L

Additional information