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Short-term toxicity to aquatic invertebrates

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Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
For details and justification of read-across please refer to the attached report in section 13 of IUCLID.
Reason / purpose for cross-reference:
read-across source
Duration:
24 h
Dose descriptor:
EC50
Effect conc.:
> 102 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 102 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
23 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Results with reference substance (positive control):
To check the reliability of the test conditions for acute toxicity studies to Daphnia magna at Seibersdorf Labor GmbH a static reference test with K2Cr2O7 is conducted at least yearly. The last reference test was conducted in December 2009 and gave a 24 h EC50 of 1.1 mg K2Cr2O7 per litre (95% confidence interval of 0.86 to 1.5 mg/L) which is within the acceptability range of 0.6–2.1 mg/L given by the OECD guideline 202.
Reported statistics and error estimates:
The EC50-values and their confidence limits were calculated with the moving average method of W. Thompson, modified by C.S. Weil, Drug and Chemical Toxicology, 6 (6), 595-603 (1983)

Table 1: Mean measured concentrations

Nominal concentration (mg/L)

Measured concentration (mg/L)

Mean (mg/L)

0 hours (new)

24 hours (old)

24 hours (new)

48 hours (old)

Control

<QL

<QL

<QL

<QL

-

6.25

5.93

4.46

6.28

4.67

5.28

12.5

12.45

9.10

12.49

8.68

10.53

25

24.44

23.69

25.51

20.55

23.47

50

49.08

50.36

49.24

50.84

49.87

100

102.86

102.41

100.67

102.36

102.07

QL: Quantification Limit of the analytical method used (3.55 mg/L)

 

 

Table 2: Immobilised Daphnia

Nominal concentration (mg/L)

Immobility

24 hours

48 hours

number

%

number

%

Control

0

0

0

0

6.25

2

10

2

10

12.5

0

0

0

5

25

0

0

0

0

50

1

5

3

15

100

2

10

4

20

20 Daphnia were exposed in each treatment

Validity criteria fulfilled:
yes
Conclusions:
Based on the geometric mean concentrations the 48-hour EC50 was determined to be > 102 mg/L. The corresponding no-observed effect concentration (NOEC) was determined to be 23 mg/L
Executive summary:

The 48-h acute toxicity of succinic acid to Daphnia magna was studied under semi-static conditions.  In order to maintain the actual test substance concentration as high as possible new test media were prepared for test media change at 24 hours after the start of the test. The pHs of the stock solutions were adjusted to that of the dilution water before addition of the test substance.


Test organisms were exposed to succinic acid at nominal concentrations of 6.25, 12.5, 25, 50 and 100 mg/L for 48 h. Concentrations of succinic acid were verified analytically at test initiation, after 24 hours in both new and old test media and test termination. Although a semi static test was conducted, the results of the analytical determination evidence that the actual test substance concentration of the medium C2 could not have been maintained to within 80 % of the initial concentration throughout the duration of the test. Therefore, the results are based on the geometric means of the actual test substance concentrations from 0 to 48 hours (5,28, 10,53, 23,47, 49,87, 102,07 mg/L).  The 48 hour EC50 was > 102 mg/L. The 48 hour NOEC based on immobilisation was 23 mg/L.


This study is classified as acceptable and satisfies the guideline requirements for an acute toxicity study with freshwater invertebrates according to OECD guideline 202.


Results Synopsis


Test organism age: < 24 h


Test type: Semi-static


48-h NOEC: 23 mg/L (corresponding to 19 mg/L succinic anhydride)


48-h EC50: > 102 mg/L (corresponding to > 86 mg/L succinic anhydride)


Endpoint(s) effected: immobilisation



This information is used in a read-across approach in the assessment of the target substance. For details and justification of read-across please refer to the read-across report attached to IUCLID section 13.


Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Justification for type of information:
For details and justification of read-across please refer to the attached report in section 13 of IUCLID.
Reason / purpose for cross-reference:
read-across source
Duration:
24 h
Dose descriptor:
EC50
Effect conc.:
68 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: 63 - 73 mg/L
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
63 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: 55 - 71 mg/L
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
25 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Results with reference substance (positive control):
To check the reliability of the test conditions for acute toxicity studies to Daphnia magna at Seibersdorf Labor GmbH a static reference test with K2Cr2O7 is conducted at least yearly. The last reference test was conducted in December 2009 and gave a 24 h EC50 of 1.1 mg K2Cr2O7 per litre (95% confidence interval of 0.86 to 1.5 mg/L) which is within the acceptability range of 0.6 - 2.1 mg/L given by the OECD guideline 202.
Reported statistics and error estimates:
The EC50-values and their confidence limits were calculated with the moving average method of W. Thompson, modified by C.S. Weil, Drug and Chemical Toxicology, 6 (6), 595-603 (1983)

Table 1: Mean measured concentrations

Nominal concentration (mg/L)

Measured concentration (mg/L)

Mean (mg/L)

0 hours (new)

24 hours (old)

24 hours (new)

48 hours (old)

Control

<QL

<QL

<QL

<QL

-

6.25

6.29

4.71

6.49

4.02

5.27

12.5

12.69

8.98

12.49

8.95

10.62

25

24.94

25.19

25.94

25.66

25.43

50

49.17

50.52

48.95

49.69

49.58

100

102.11

103.0

100.91

93.31

99.79

QL: Quantification Limit of the analytical method used (3.55 mg/L)

 

 

Table 2: Immobilised Daphnia

Nominal concentration (mg/L)

Immobility

24 hours

48 hours

number

%

number

%

Control

0

0

2

10

6.25

1

5

1

5

12.5

1

5

1

5

25

1

5

2

10

50

1

5

3

15

100

20

100

20

100

20 Daphnia were exposed in each treatment

Validity criteria fulfilled:
yes
Conclusions:
The 48-hour EC50was determined to be 63 mg/L with 95% confidence limits of 55 to 71 mg/L. The corresponding no-observed effect concentration (NOEC) was determined to be 25 mg/L.
Executive summary:

The 48hr-acute toxicity of succinic acid to Daphnia magna was studied under semi-static conditions. In order to maintain the actual test substance concentration as high as possible, new test media were prepared for test media change at 24 hours after the start of the test. The test was performed without pH adjustment of the test media and due to the acidic nature of the test substance the pH of the relevant test media ranged from 4.7 to 7.7.

 

Test species were exposed to succinic acid at nominal concentrations of 6.25, 12.5, 25, 50 and 100 mg/L for 48hr. Concentrations of succinic acid were verified analytically at test initiation, after 24 hours in both new and old test media and test termination. Although a semi static test was conducted, the results of the analytical determination evidence that the actual test substance concentrations of the media C1 and C2 could not have been maintained to within 80% of the initial concentration throughout the duration of the test. Therefore the results are based on the geometric means of the actual test substance concentrations from 0 to 48 hours (5.27, 10.62, 25.43, 49.58 and 99.79 mg/L). The 48 hour EC50 was 63 mg/L with 95% confidence limits of 55 to 71 mg/L.  The 48 hr NOEC based on immobilization was 25 mg/L.

 

This study is classified as acceptable and satisfies the guideline requirements for an acute toxicity study with freshwater invertebrates according to OECD guideline 202.

 

Results Synopsis

 

Test Organism Age: <24hr

Test Type: semi-static conditions

 

NOEC:  25 mg/L (corresponding to 21 mg/L succinic anhydride)

EC50:  63 mg/L   (correspoding to 53 mg/L succinic anhydride)              95% C.I.:  55 to 71 mg./L

Endpoint(s) Effected: immobilization

This information is used in a read-across approach in the assessment of the target substance. For details and justification of read-across please refer to the read-across report attached to IUCLID section 13.

Description of key information

The potential toxicity of succinic anhydride to aquatic invertebrates is assessed via read-across from its hydrolytical transformation product succinic acid.


The 48 hour acute toxicity of succinic acid to Daphnia magna was determined in two semi-static tests according to OECD guidline 202 (13 April 2004). In the first experiment the acidic pH of the test solution was unchanged, but in the second experiment the pH was adjusted to the neutral pH of the daphnid medium.  In order to maintain the actual test substance concentration, new test media were prepared for test medium change at 24 hours after the start of both tests.


Test organisms were exposed to succinic acid at nominal concentrations of 6.25, 12.5, 25, 50 and 100 mg/L for 48 h in both tests. Concentrations of succinic acid were verified analytically at test initiations, after 24 hours in both new and old test media and test terminations. Although semi-static tests were conducted, the results of the analytical determinations show that the actual test substance concentrations of the medium C2 could not have been maintained to within 80 % of the initial concentrations throughout the duration of the tests. Therefore, the results are based on the geometric means of the actual test substance concentrations from 0 to 48 hours (5.28, 10.53, 23.47, 49.87, 102.07 mg/L (pH adjustment) and 5.27, 10.62, 25.43, 49.58 and 99.79 mg/L (no pH adjustment)). The 48-hour EC50 was 63 mg/L with 95 % confidence limits of 55 and 71 mg/L in the study without pH adjustment and > 102mg/L in the study with pH adjustment. The 48-h NOEC based on immobilisation was 25 mg/L in the study without pH adjustment and 23 mg/L in the study with pH adjustment.


Based on the fact that the effects seen in the first experiment were influenced by the pH change, the most appropriate endpoint to use for the assessment of succinic anhydride toxicity is the 48-hour EC50 value of > 102 mg/L obtained in the study with pH adjustment corresponding to > 86 mg/L succinic anhydride.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Effect concentration:
86 mg/L

Additional information

In the study without pH adjustment, the pH ranged from 4.7 in the 100 mg/L treatment to 7.4 in the 6.25 mg/L treatment in a dose related response. In the study with pH adjustment, the pH of the stock solutions used to prepare the test media was adjusted to that of the dilution water before addition of the test substance and maintained between 7.5-8.0. The comparison of the derived EC50 values of both studies indicates that the EC50 values derived in the experiment without pH adjustment are influenced by the acidic nature of the test substance.