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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
Study period:
Study plan 06 December2002, Final report 04 March 2003, Amendment to the final report 25 February 2004
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study and GLP

Data source

Referenceopen allclose all

Reference Type:
study report
Title:
Unnamed
Year:
2003
Reference Type:
study report
Title:
Unnamed
Year:
2004
Report Date:
2004

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

Sampling and analysis

Analytical monitoring:
yes

Test solutions

Vehicle:
no
Details on test solutions:
In a separate test the stability of the test substance was determined in distilled water and in OECD 201 test medium. In the range of the effect concentrations determined in the algal toxicity test, the test substance was found to be quite unstable in the test medium. In the lower test concentrations the test substance virtually was completly depleted within 24 hours.

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
The test laboratory obtained the culture of Desmodesmus subspicatus in May 2002 from the 'Collection of Algae', Institut für Pflanzenphysiologie, University of Göttingen.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h

Test conditions

Hardness:
Artificial test medium according OECD 201
Test temperature:
23±2 °C
pH:
Artificial test medium according OECD 201
Dissolved oxygen:
not relevant
Salinity:
Artificial test medium according OECD 201
Nominal and measured concentrations:
Nominal and effective concentrations at the start of the toxicity test

nominal conc. (mg/L) recovery rate (%) at time 0 eff. conc. (mg/L)
0 0 0
100,8 100 100,8
63,5 100 63,5
0,3 97 39,1
25,2 95 23,9
16,1 84 13,5
10,1 94 9,5
6,3 89 5,6
4,0 89 3,6
2,5 94 2,4

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
15 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: >8.4 mg/L 95% CL
Duration:
72 h
Dose descriptor:
other: EbC50
Effect conc.:
4.2 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Remarks on result:
other: 1.9-6.1 mg/L 95% CI

Any other information on results incl. tables

 24h ErC50   3.1 mg/L
 24h EbC50  2.0 mg/L
 48h  ErC50  8.7 mg/L
 48h  EbC50  2.9 mg/L
 72h  ErC50  15 mg/L
 72h  EbC50  4.2 mg/L

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
Ro 1525 was tested according to OECD Guideline 201 and reached after 72 hours an EC50 of 4.2 mg/L against the freshwater algae Desmodesmus subspicatus based on growth rate. Based on biomass the 72 hours EC50 was found to be 15 mg/L
Within an exposure period of 24 hours an EC50 of 2.0 was determined based on biomass. The related 24 hours EC50 based on growth rate was found to be 3.1 mg/L.
Within an exposure period of 48 hours an EC50 of 2.9 was determined based on biomass. The related 48 hours EC50 based on growth rate was found to be 8.7 mg/L.
For reasons of conservative evaluation of the results the 24h EC50 of 2.0 mg/L based on biomass is regarded as key date for the algal toxicity of Ro 1525.
Executive summary:

Ro 1525 was tested according to OECD Guideline 201 and reached after 72 hours an EC50 of 4.2 mg/L against the freshwater algae Desmodesmus subspicatus based on growth rate. Based on biomass the 72 hours EC50 was found to be 15 mg/L

Within an exposure period of 24 hours an EC50 of 2.0 was determined based on biomass. The related 24 hours EC50 based on growth rate was found to be 3.1 mg/L.

Within an exposure period of 48 hours an EC50 of 2.9 was determined based on biomass. The related 48 hours EC50 based on growth rate was found to be 8.7 mg/L.

For reasons of conservative evaluation of the results the 24h EC50 of 2.0 mg/L based on biomass is regarded as key date for the algal toxicity of Ro 1525.