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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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study under GLP
Remarks:
(as given in OECD SIDS)
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
GLP compliance:
yes
Analytical monitoring:
yes
Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Key result
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
>= 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
>= 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass

Nominal concentrations (as mg/L): 1,000

Measured concentrations (as mg/L): 954 (Day 0)- 927 (Day 3)

Unit [results expressed in what unit]: Cell density (cells/mL)

Element value: ErC50 > 1,000 mg/L (24-72 h); NOEC(r) >= 1,000 mg/L,

EbC50 > 1,000 mg/L (0-72 h); NOEC(b) >= 1,000 mg/L calculated based on nominal concentration.

Was control response satisfactory: Yes: mean cell density increased to 2.78 E6 cells/mL in control after 72 h.

Statistical results: Significant difference was not detected between values at 1,000 mg/L and in control.

 

- Biological observations

· Cell density at each flask at each measuring point: 

   

Nominal

Concentration

Measured

concentration

Cell concentration for each exposure (x E4 cells/mL)b

(mg/L)

(mg/L)

0 h

24 h

48 h

72 h

Control

-

1.0

5.2±0.2

44.6±4.7

278.3±8.5

1,000

927-954a

1.0

5.6±0.7

46.0±3.1

270.6±10.5

 

a : value at start and end of the test

b : mean ± standard deviation

Growth curves:

Percent biomass/growth rate inhibition per concentration:

1.1 % for area under growth curve (0-72 h) 

2.0 % for growth rate (24-48 h) 

2.5 % growth rate (24-72 h) 

Reference substance result: 72h-EbC50 of potassium bichromate; 0.423 mg/L

Conclusions:
There was no statistical significant difference in inhibition rate compared with the Control, and 72h-EC50 were greater than 1,000 mg/L and 72h-NOEC were more than 1,000 mg/L.

Description of key information

EC50 (growth and biomass) >1000 mg/L, NOEC (growth and biomass) ≥1000 mg/L for Pseudokirchneriella subcapitata (OECD TG 201)

Key value for chemical safety assessment

Additional information

Value used for CSA:

EC50/LC50 for freshwater algae: >1000 mg/L

EC10, LC10 or NOEC for freshwater algae: ≥1000 mg/L