Registration Dossier

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
Study period:
2008
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Version / remarks:
2006
Deviations:
no
GLP compliance:
yes
Analytical monitoring:
no
Details on sampling:
The report contains the following statement:

Samples of the stock solution and the highest tested concentration at 0 h and 72 h were collected and stored in the freezer until analysed by the sponsor.

No analytical results have been provided.
Vehicle:
no
Details on test solutions:
10 003 mg of the test item was solved in 1 000 mL growth medium by magnetic stirring on the day of the test start. The test solutions were made by dilution of the stock solution (approx. 10 000 mg/l) with growth medium (specified below). The pH of the stock solution was adjusted from 7,2 to 8,0 with 0,1 M NaOH prior making of the test solutions.
Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
The test organism is a laboratory culture of the green alga Pseudokirchneriella subcapitata (earlier known as Raphidoceles subcapitata and/or Selenastrum capricornutum). The inoculum is taken from Toxicon’s culture of P. subcapitata (NIVA CHL 1), which originates from NIVA, Oslo, Norway.
Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Hardness:
Not applicable
Test temperature:
21-24±2oC
Dissolved oxygen:
Not applicable
Salinity:
Not applicable
Conductivity:
Not applicable
Nominal and measured concentrations:
Nominal test concentrations were 0 (control), 312, 625, 1250, 2500, 5000 and 10000 mg/L.
Details on test conditions:
For each test concentration, triplicates were used and for the controls six replicates were used. Test bottles were 250 mL glass Ebottles with 100 mL solution that were incubated on a shaking table with approximately 100 μE m-2 s-1 continuous illumination at a temperature of 21-24±2° C.

The pH was measured in the controls and in one replicate of each concentration at the start of the experiment. The pH was again measured in the same replicates after 72 hours.

The incubation period was 72 hours with sampling at 0, 24, 48, and 72 hours.

As a measurement of the biomass in the samples, the number of cells/ml was counted by microscope.
Reference substance (positive control):
yes
Remarks:
Actual reference substance used not named.
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
2 512 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
495 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
312 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Results with reference substance (positive control):
The report contains the following statement:
A qualification test on the alga culture was made on the 5 June 2008 to assure the quality of the test animals. ErC50 was 1,5 mg/l, which confirmed that the culture was suitable as a test organism according to OECD TG no. 201
Reported statistics and error estimates:
The EC-values was calculated by means of graphic interpolation. The NOEC-value is the highest tested concentration not statistically different from the controls (Mann-Whitney U-test p > 0,05).
Validity criteria fulfilled:
yes
Conclusions:
The 72 hour EC50 based on specific algal growth rate is 2512 mg/L.
Executive summary:

An EC50-value of 2512 mg/L was found for the response variable average specific growth rate. Since the EC50-value was above 100 mg/L, the test item can be regarded as not acute toxic towards the green algae Pseudokirchneriella subcapitata.

Description of key information

In an OECD 201 test the 72-hour EC50 for growth rate was found to be 2512 mg/L, and the NOEC for growth rate was found to be 312 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:
2 512 mg/L
EC10 or NOEC for freshwater algae:
312 mg/L

Additional information

An EC50-value of 2512 mg/L was found for the response variable average specific growth rate. Since the EC50-value was above 100 mg/L, the test item can be regarded as not acute toxic towards the green algae Pseudokirchneriella subcapitata.