Registration Dossier

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
other company data
Title:
Unnamed
Year:
2013
Report Date:
2013

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent

Test solutions

Details on test solutions:
The standard test procedures required generation of test solutions, which contained completely dissolved test substance concentrations or stable and homogeneous mixtures or dispersions. The testing of concentrations that would disturb the test system was prevented as much as possible (e.g. film of the test substance on the water surface.)
Preparation of test solutions started with a concentration of 100 mg/l. No other treatment than vigorous shaking was needed to completely dissolve the test substance in the medium. The lower test concentrations for the range-finding test were prepared by subsequent dilutions of the highest concentration in test medium. The final test solutions were all clear and ranged from colourless to orange.

Test organisms

Details on test organisms:
TEST ORGANISM
- Common name: Pseudokirchnerella subcapitata
- Strain: NiVA CHL 1
- Source (laboratory, culture collection): In-house laboratory culture.
- Method of cultivation:Algae stock cultures were started by inoculating growth medium with algal cells from a pure culture on agar. The suspensions were continuously aerated and exposed to light in a climate room at a temperature of 21-24℃.
ACCLIMATION
- Acclimation period: 3 days before the start of the test, cells from the algal stock culture were inoculated in culture medium at a cell density of 1 x 10E4 cells/ml. The pre-culture was maintained under the same conditions as used in the test. The cell density was measured immediately before use.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Post exposure observation period:
at t=0 h, t=24 h and t=72 h

Test conditions

Hardness:
24 mg CaCO3/L
Test temperature:
21-24℃
pH:
8.1
Nominal and measured concentrations:
0.1, 1, 10 and 100 mg/l
Reference substance (positive control):
yes
Remarks:
potassium dichromate

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
meas. (TWA)
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
100 mg/L
Nominal / measured:
meas. (TWA)
Basis for effect:
growth rate
Results with reference substance (positive control):
Potassium dichromate reduced growth rate of this fresh water algae species at nominal concentrations of 0.56 mg/l and higher.

The EC50 for growth rate reduction (ERC50: 0-72h) was 2.3 mg/l with a 95% confidence interval ranging from 1.9 to 2.9 mg/l. The historical ranges for growth rate reduction lie between 0.82 and 2.3 mg/l. Hence, the ERC50: 0-72h for the algal culture tested corresponds with this range.

The EC50 for yield inhibition (EYC50: 0-72h) was 0.90 mg/l with a 95% confidence interval ranging from 0.68 to 1.2 mg/l. The historical ranges of the 72h EC50 for yield inhibition lie between 0.43 and 1.1 mg/l. Hence, the EYC50: 0-72h for the algal culture tested corresponds with this range.

Any other information on results incl. tables

Effect parameters

Parameter

Concentration Everzol SB44

(mg/l)

72h-NOERC

100

72h-ERC50

>100

72h-NOEYC

100

72h-EYC50

>100

 

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
Under the conditions of the present study with Pseudokirchneriella subcapitata, no reduction of growth rate or inhibition of yield was recorded at the limit concentration being 100 mg Everzol SB44 per litre.

The EC50 for growth rate reduction (72h-ERC50) and the EC50 for yield inhibition (72h-EYC50) were beyond the range tested, i.e. exceeded an analytically confirmed nominal concentration of 100 mg/l.

The NOEC for both growth rate reduction and yield inhibition was 100 mg/l.