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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Reference
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
October 1992 - January 1993
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
no
GLP compliance:
yes
Remarks:
This study has been performed in compliance with GLP in Switzerland, Procedures and Principles, March 1986, issued by the Swiss federal Department of the Interior and the Intercantonal Office for the Control of Medicaments.
Analytical monitoring:
yes
Vehicle:
no
Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Key result
Duration:
72 h
Dose descriptor:
other: EbC50 (0-72 h), calculated values
Effect conc.:
3.8 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
cell number
Remarks:
cell density
Remarks on result:
other: 95% CL: none
Duration:
72 h
Dose descriptor:
other: NOEbC (0-72 h) (5 % level)
Effect conc.:
1.1 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
cell number
Remarks:
cell density
Remarks on result:
other: values observed

Inhibition of algal growth:

 

Conc.

nominal

mg/l

Areas under Growth Curves (A) *10000

Mean A

Inhibition *

IA 0-72 h

(%)

 

1

2

3

4

5

6

 

 

Blank

1763

1919

2084

2004

2222

2273

2044

0.0

0.041

2213

1846

2088

 

 

 

2049

0.0

0.123

2495

2528

2275

 

 

 

2433

0.0

0.370

2488

2633

2326

 

 

 

2482

0.0

1.1

2108

2339

2180

 

 

 

2209

0.0

3.3

468

431

313

 

 

 

404

80.2

10

42

41

55

 

 

 

46

97.7


* promotion of algal growth in regard to control is indicated as 0

Validity criteria fulfilled:
yes
Remarks:
As stated in the report there were no deviations from OECD Guideline 201.
Conclusions:
EbC50,0-72h: 3.8 mg/l
NOEbC0-72h: 1.1 mg/l
Executive summary:

This study was conducted to determine the growth inhibition of CA 1139 A to Green Algae (Scenedesmus subspicatus).

The test was performed according to the OECD guideline 201.

Each test concentration was tested in 3 replicates, the blank control in 6.

Duration time of the test was 72h.

Cell densities were measured at 24, 48 and 72h exposure on a "TOA" cell counter.

Temperature was continuously measured and maintained at 23 +/- 1 °C.

pH was measured at 0 and 72h exposure.

The following results were calculated:

EbC50,0-72h: 3.8 mg/l

NOEbC0-72h: 1.1 mg/l

Values are based on nominal concentrations.

Description of key information

This study was conducted to determine the growth inhibition of CA 1139 A to Green Algae

(Scenedesmus subspicatus).
The test was performed according to the OECD guideline 201.
Each test concentration was tested in 3 replicates, the blank control in 6.
Duration time of the test was 72h.
Cell densities were measured at 24, 48 and 72h exposure on a "TOA" cell counter.
Temperature was continuously measured and maintained at 23 +/- 1 °C.
pH was measured at 0 and 72h exposure.
The following results were calculated:
EbC50,0-72h: 3.8 mg/l
NOEbC0-72h: 1.1 mg/l
Values are based on nominal concentrations.

Key value for chemical safety assessment

EC50 for freshwater algae:
3.8 mg/L

Additional information

 

Guideline Test Type

Species

Conclusion

 Reference

Reliability

 

OECD 201

Scenedesmus subspicatus (new name: Desmodesmus subspicatus)

EbC50(0-72 h): 3.8 mg/l

NOEbC (0-72 h): 1.1 mg/l

Grade R., Ciba-Geigy, 1993

Reliable without restrictions