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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:
2003-2004
Reliability:
1 (reliable without restriction)

Data source

Reference
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
Test material form:
solid: particulate/powder
Remarks:
migrated information: powder

Test solutions

Details on test solutions:
Identity and concentration of auxiliary solvent for dispersal: None.

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Study design

Limit test:
yes
Total exposure duration:
72 h

Test conditions

Hardness:
24 mg CaCO3/L

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
100 mg/L
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
100 mg/L
Basis for effect:
biomass
Details on results:
%Concentration loss over test: ... 0

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The test item ucb 22060 had clearly no inhibitory effect on the growth of Scenedesmus
subspicatus during the exposure period of 72 hours at the test concentration of 100 mg/L.
Executive summary:

A limit test was performed in accordance with the EU Commission Directive 92/69/EEC to demonstrate that the test item has no toxic effect on Scenedesmus subspicafus up to a nominal concentration of 100 mg/L. The test item concentration in the samples from the stad and the end of the test was 101 YO of the nominal value (see analytical results and Table 2 in the attached analytical phase report). Under the conditions of the test, the test item ucb 22060 was stable during the test period of 72 hours. Therefore, all reported results are related to the nominal concentration of the test item. The mean algal cell densities in the treated test medium of 100 mg/L were nearly identical with those in the parallel control culture throughout the entire test duration (Table 1 and Figure 1). According to a t-test (u=O.05, one-sided smaller) the mean algal cell densities in the test medium were statistically not significantly different to the mean cell densities in the parallel control cultures after the exposure period of 72 hours. Thus, the test item ucb 22060 clearly had no inhibitory effect on the growth of Scenecfesmus subspicatus during the exposure period of 72 hours at a nominal test concentration of 100 mg/L. This test concentration was therefore determined as the 72-hour NOEC (highest concentration tested without toxic effects after a test period of 72 hours). This value might even be higher, but concentrations in excess of 100 mg/L have not been tested, according to EU Commission Directive 92/69/EEC. The 72-hour LOEC (lowest concentration tested with toxic effects), and the 72-hour EC50 for the algal biomass b and growth rate r could not be quantified due to the absence of a toxic effect of ucb 22060 at the tested concentration. However, these parameters were clearly higher than 100 mg/L. The microscopic examination of the algal cells after 72 hours exposure showed no difference between the algae growing in test medium containing the test item at a nominal concentration of 100 mg/L and the algal cells in the control. There were no obvious effects on the shape and size of the algal cells growing in the test medium at this nominal concentration. In the control the cell density increased from nominal N = 1 x 104 cells/mL at the start of the test (Ohours) to N = 99 x 104 cells/mL (mean value) after 72 hours (Table 1). Thus, the algal growth in the control was sufficiently high under the conditions of the test. Therefore, the validity criterion of increase of cell density by at least a factor of 16 over the duration of the study was fulfilled. No remarkable observations were made concerning the appearance of the test medium. It remained a clear solution throughout the test period (Table 2). At the start of the test, the pH values in the test medium and the control ranged from 8.0 to 8.1. At the end of the test, pH values between 9.1 and 9.2 were measured (Table 3). The water temperature was constantly 23 “C (Table 4).