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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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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: GLP and appropriate guidelines
Cross-referenceopen allclose all
Reason / purpose:
reference to same study
Reason / purpose:
reference to other study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2007
Report Date:
2007

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Qualifier:
according to
Guideline:
other: EEC 192. Algal growth inhibition test. Off. J. Of the European communitiea, L383 A/179, 1992-12-29.
Qualifier:
according to
Guideline:
ISO 8692 (Water Quality - Fresh Water Algal Growth Inhibition Test with Scenedesmus subspicatus and Selenastrum capricornutum)
Principles of method if other than guideline:
The test item is poorly soluble in water and therefore Water Accomodated Fraction (WAF) of the test substance was tested. A toxicity test was performed using nominal concentration of 1, 10, 100 and 1000 mg/l test substance and a control.
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
E-AF098T (Batch No. T# 176-3), a white powder. Stored at room temp, dry, closed container.
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
not relevant

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
At the beginning of the test, samples of initial stock were taken. As particles in all WAFs were found to be both floating at the top of the solution and lying on the bottom of the volumetric flask, the test solutions were carefully siphoned off from the middle of the volumetric flasks and transfered to 10 mL HPLC vials and stored at room temperature in the dark. For the samples at the end of the test, replicates were pooled and transfered to 10 mL HPLC vials (in triplicate) and stored at room temperature in the dark. The amount of E-AF098T present in the tested concentrations was quantified by HPLC. The HPLC analyses were performed according to SOP K 19.

Test solutions

Vehicle:
no
Details on test solutions:
The test solutions were prepared as water accomodated fractions (WAF) prepared from 0.00127 g test substance in 1000 mL OECD medium to make the 1 mg/L loading, from 0.0105 g test substance in 1000 mL OECD medium to make the 10 mL loading, from 0.1005 g test substance in 1000 mL OECD medium to make the 100 mg/L loading and from 1.004 g test substance in 1000 mL OECD medium to make the 1000 mg/L loading. The test substance was weighed into a beaker and rinsed into a 1000 mL volumetric flask then filled up to the mark with OECD medium. The substance was allowed to dissolve during 41 hours of stirring at room temperature. The prepared WAF was then allowed to settle overnight and, as particles in all WAFs were found to be both floating at the top of the solution and lying on the bottom of the volumetric flask, the test solutions were carefully siphoned off from the middle of the volumetric flasks into their respective test vessels.
No further dilutions of the stock solution were prepared.

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
The freshwater algae P. subcapitata (CCAP 278/4) obtained from the culture Collection of Algae and Protozoa, Institute of Freshwater Ecology. The Windermere Laboratory, Cumbria, Ambleside, United Kingdom. After purchasing, this strain was cutured and maintained according to Standard Operation Precedure E 3 (See ref. 9.10 in the attached report). Cultures on sloped agar tubes were stored at 4°C until required.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Post exposure observation period:
No abnormalities were observed.

Test conditions

Hardness:
18 mg/L CaCl2(H2o)2
Test temperature:
23.1-23.9°C
pH:
8.2-8.4
Dissolved oxygen:
??Didn't find...
Salinity:
not relevant
Nominal and measured concentrations:
Samples were quantified using a calibration curve of external standards. More details on analysis, see attched report, pp. 21-25.
Details on test conditions:
The objective of this algal growth inhibition test was to determine the effect of the Water Accommodated Fraction (WAF) of E-AF098T on the growth of a freshwater unicellular green alga. In the present toxicity test exponentially growing cultures of Pseudokirchneriella subcapitata were exposed to 1, 10, 100 and 1000 mg/L of the test substance over several generations under defined conditions. The inhibition of growth in relation to control cultures was determined during 72 hours.

An amount of culture medium was prepared and sterilized. Adequate amounts of test substance were added and allowed to dissolve. The flasks were then filled with test solution. Then the inoculum was added to the vessel from an exponentially growing culture. All test concentrations were tested in triplicates. In addition, six replicates of the control were included. The absorbance in each flask was measured after 0, 24, 48 and 72 hours. Algal medium was used as a blank in the spectrophotometer.


Reference substance (positive control):
yes
Remarks:
Potassium dichromate

Results and discussion

Effect concentrationsopen allclose all
Duration:
24 h
Dose descriptor:
EC50
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
dissolved
Basis for effect:
other: growth rate & biomass
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
dissolved
Basis for effect:
other: growth rate & biomass
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
dissolved
Basis for effect:
other: growth rate & biomass
Duration:
24 h
Dose descriptor:
NOEC
Effect conc.:
>= 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
dissolved
Basis for effect:
other: growth rate & biomass
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
>= 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
dissolved
Basis for effect:
other: growth rate & biomass
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
>= 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
dissolved
Basis for effect:
other: growth rate & biomass
Details on results:
No effects were seen and therefore a NOEC equal to or greater than 1000 mg/L was determined. The EC50 values were greater than the tested concentration of 1000 mg/L. The chemical analyses performed showed that the concentration of test substance in the WAF at 1 up to 100 mg/L were all < LOQ (=0.02mg/L) at the beginning and end of the test. For the WAF solution 1000 mg/L measured concentrations of 0.119 mg/L (t = 0h) and 0.073 mg/L (t = 72h) were found.
Results with reference substance (positive control):
The sensitivity of the algae was checked by performing a growth inhibition test with the reference substance as mentioned above, because the growth in the controls was not satisfactory. The sensitivity was tested for compliance with the guidelines, which means that the EC50 values are between 0.25 and 2.0 mg/L.
Reported statistics and error estimates:
See pages 27-30 in the attached report.

Any other information on results incl. tables

No further details

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
No effects were seen and therefore a NOEC equal to or greater than 1000 mg/L was determined. The EC50 values were greater than the tested concentration of 1000 mg/L.
Executive summary:

The toxicity of the test item to an exponentially growing culture of the green algae P. subcapitata was determined over an exposure of 72 hours. No effects were seen and therefore a NOEC equal to or greater than 1000 mg/L was determined. The EC50 values were greater than the tested concentration of 1000 mg/L.