Registration Dossier

Diss Factsheets

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Qualifier:
according to guideline
Guideline:
other: German industrial standard test guideline DIN 38412, part 9
Principles of method if other than guideline:
Method used is comparable to OECD TG 201 (Freshwater Algae and Cyanobacteria, Growth Inhibition Test)
GLP compliance:
no
Analytical monitoring:
no
Vehicle:
no
Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Strain: SAG 86.81
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Test temperature:
20 °C
Nominal and measured concentrations:
Nominal concentrations (mg/l): control, 3.9, 7.8125, 15.625, 31.25, 62.5, 125, 250, 500 mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel: Erlenmeyer vessels
- Material, size, headspace, fill volume: glass, 10 ml fill volume
- Initial cells density: 10 000 cells/ml

GROWTH MEDIUM
- Standard medium used: OECD medium

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: fluorimeter
- Observation intervals: 0, 24, 48 and 72 h
Reference substance (positive control):
no
Key result
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
29.4 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
45.1 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
EC90
Effect conc.:
76.4 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
EC20
Effect conc.:
30.2 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: fluorescence
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
44.7 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: fluorescence
Duration:
72 h
Dose descriptor:
EC90
Effect conc.:
75.8 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: fluorescence
Details on results:
- Exponential growth in the control (for algal test): yes
- Any stimulation of growth found in any treatment: at low test substance concentrations

Measured algal cell density (fluorescence) after 0 h, 24 h, 48 h and 72 h (relative units, mean of 4 replicates)

 

Nominal Concentrations
[mg/L]

Time

0 h

24 h

48 h

72 h

0 (controls)

106.7 ± 3.58

227.7 ± 15.79

892.2 ± 114.9

2327.6 ± 196.37

3.9

105.6 ± 3.5

277.4 ± 11.68

1037.5 ± 42.94

2653.7 ± 166.35

7.8

108.3 ± 3.22

269.7 ± 4.8

1000.2 ± 20.09

2448.5 ± 58.61

15.6

108.5 ± 4.02

266.7 ± 23.39

993.1 ± 126.35

2398.1 ± 305.27

31.25

103.3 ± 6.01

263.3 ± 25.68

860.9 ± 89.82

1823.6 ± 253.33

62.5

96.8 ± 3.29

181.9 ± 6.27

238.2 ± 34.85

290.7 ± 86.91

125

83.4 ± 1.86

56.6 ± 1.77

44.1 ± 1.46

33.1 ± 3.53

250

77.1 ± 2.75

55.6 ± 0.62

34.6 ± 1.73

12.9 ± 0.94

500

70.7 ± 2.6

44.1 ±0.93

9.7 ± 0.97

6.1 ± 2.37

 

Validity criteria fulfilled:
yes
Executive summary:

In a 72-h acute toxicity study similar to OECD TG 201, cultures of Scenedesmus subspicatus (new name Desmodesmus subspicatus), strain SAG 86.81, were exposed to isobutyric acid at nominal concentrations of 0 (controls), 3.9, 7.8, 15.6, 31.25, 62.5, 125, 250, and 500 mg/L under static conditions. Cell density was recorded at 0, 24, 48 and 72h by fluorescence measurement.

The 72 -h EC10 was determined to be 29.4 mg/L (BASF AG, 1990)

The 72-h EC50 was determined to be 44.7 mg/L (BASF AG, 1990).

 

This toxicity study is acceptable and adequate to satisfy the information requirements for the toxicity to aquatic algae.

Description of key information

In a valid growth inhibition test with green algae similar to OECD TG 201, the EC50 of isobutyric acid was determined to be 45.1 mg/L (BASF AG, 1990)

Key value for chemical safety assessment

EC50 for freshwater algae:
45.1 mg/L
EC10 or NOEC for freshwater algae:
29.4 mg/L

Additional information

The toxicity of isobutyric acid to aquatic algae was investigated in two studies. One study is only reported in a Handbook, thus reliability of the data cannot be assessed (Verschueren, 1983). The second study (BASF AG, 1990) was performed according to a German test guideline (DIN 38412 part 9) which is comparable to OECD TG 201. Reliability is 2.

 

BASF 1990

 

In a 72-h acute toxicity study similar to OECD TG 201, cultures of Scenedesmus subspicatus (new name Desmodesmus subspicatus), strain SAG 86.81, were exposed to isobutyric acid at nominal concentrations of 0 (controls), 3.9, 7.8, 15.6, 31.25, 62.5, 125, 250, and 500 mg/L under static conditions. Cell density was recorded at 0, 24, 48 and 72h by fluorescence measurement.

 

The 72-h EC50 was determined to be 45.1 mg/L (BASF AG, 1990).

Categories Display