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)
Rationale for reliability incl. deficiencies:
other: Follows a recognised guideline and performed to GLP standards.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2008
Report Date:
2008

Materials and methods

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

Test material

Reference
Name:
Unnamed
Type:
Constituent

Sampling and analysis

Analytical monitoring:
yes

Test solutions

Vehicle:
no
Details on test solutions:
100 mg of test material was dissolved directly in culture medium and the volume was adjusted to 500 ml to give a 200 mg/l stock solution. This stock solution was mixed with algal suspension (500 ml) to give the required test concentration of 100 mg/l.

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
Test used Desmodesmus subspicatus strain CCAP 276/20. Liquid cultures were obtained from the Culture Collection of Algae and Protozoa (CCAP), Dunstaffnage Marine Laboratory, Oban, Argyll, Scotland. Master Cultures were maintained in the laboratory by the periodic replenishment of culture medium. The master cultures were maintained in the laboratory under constant aeration and constant illumination at 21 +/- 1 C.

Prior to the start of the test sufficient master culture was added to 100 ml volumes of culture media contained in conical flasks to give an initial cell density of 10^3 cells/ml. The flasks were constantly agitated by an orbital shaker (100 - 150 rpm) and constant illumination at 24 +/- 1 C until the algal cell density was approximately 10^4 - 10^5 cells/ml.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
72 h

Test conditions

Test temperature:
24 +/- 1 C
pH:
7.1 - 7.2
Nominal and measured concentrations:
Range finding test: nominal concentrations of 0.1, 1.0, 10 and 100 mg/L were exposed to Desmodesmus subspicatus for a period of 72 hours.
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: 100 ml
- Aeration: none
- Initial cells density: 4E3 (nominal)
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 6

OTHER TEST CONDITIONS
- Photoperiod: 72 hours
- Light intensity and quality: 7000 lux provided by warm white lighting (380 - 730 nm)


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: Coulter Multisizer particle counter


TEST CONCENTRATIONS
- Range finding study
- Test concentrations: 0.1, 1.0, 10, 100 mg/L
- Results used to determine the conditions for the definitive study: 100 mg/L
Reference substance (positive control):
yes
Remarks:
potassium dichromate

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
> 100 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks:
, cell number and biomass
Duration:
72 h
Dose descriptor:
EC20
Effect conc.:
> 100 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks:
, cell number and biomass
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks:
, cell number and biomass
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
100 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks:
, cell number and biomass
Details on results:
Range-finding test: The cell densities and percentage inhibition of growth values from the exposure of Desmodesmus subspicatus to the test material during the range-finding test are given in table 1 below. The results showed no effect on growth at the test concentrations of 0.10, 1.0, 10 and 100 mg/l.

No data on 95% CL.
Results with reference substance (positive control):
- Results with reference substance valid? yes
- ECr50: 0.57 mg/l
- ECy50: 0.32 mg/l
- ECb50: 0.31 mg/l
- NOEC based on growth rate: 0.25 mg/l
- NOEC based on yield: 0.0625 mg/l
- NOEC based on biomass integral: 0.0625 mg/l
- LOEC based on growth rate: 0.50 mg/l
- LOEC based on yield: 0.125 mg/l
- LOEC based on biomass integral: 0.125 mg/l

Any other information on results incl. tables

Table 1: range-finding test results

  Nominal concentration (mg/l) Cell densities* (cells/ml) Inhibition values (%)
0 hours 72 hours Growth rate Yield.Biomass integral
Control R1 4.04E+03 1.32E+05 - -
R2 4.45E+03 1.09E+05
Mean 4.25E+03 1.20E+05
0.10 R1 4.31E+03 1.13E+05 [4] [16]
R2 4.60E+03 1.66E+05
Mean 4.45E+03 1.39E+05
1.0 R1 4.30E+03 1.09E+05 43 11
R2 4.54E+03 1.06E+05
Mean 4.42E+03 1.07E+05
10 R1 4.24E+03 1.24E+05 [2] 4
R2 3.87E+03 1.07E+05
Mean 4.05E+03 1.16E+05
100 R1 4.04E+03 1.26E+05 [11] [39]
R2 4.26E+03 2.03E+05
Mean 4.15E+03 1.65E+05

* Cell densities represent the mean number of cells per ml calculated from the mean of the cell counts from 3 counts for each of the replicate flasks.

R1 and R2 = Replicates 1 and 2

[] = increase in growth compared to controls.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The effect of the test material on the growth of Desmodesmus subspicatus has been investigated and gave EC50 values of greater than 100 mg/l. Correspondingly the NOEC was 100 mg/l.
Executive summary:

In a 72- hour acute toxicity study, the cultures of Desmodesmus subspicatus were exposed to trisodium 6,6',6"-(1,3,5-triazine-2,4,6-triyltriimino)trihexanoate at nominal concentrations of 100 mg a.i./L under static conditions in accordance with the OECD Guideline 201 (Alga, Growth Inhibition Test).  The NOEC and EC50values based on cell density, growth rate and biomass were 100 and >100 mg a.i./L, respectively. 

 

There were no compound related phytotoxic effects.

 

This toxicity study is classified as acceptable and satisfies the guideline requirements for OECD Guideline 201 (Alga, Growth Inhibition Test) toxicity study.

 

Results Synopsis

 

Test Organism: Desmodesmus subspicatus

Test Type (Flowthrough, Static, Static Renewal): static

 

72h EC50:  > 100 mg a.i./L               

72h NOEC:  100 mg a.i./L                   

(EC50 and NOEC for cell density, growth rate and biomass)