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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:
31 March 2003 - 4 April 2003
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The study has been performed according to OECD and/or EC guidelines and according to GLP principles. Limited information available to verify the composition of the used test substance.

Data source

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

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Version / remarks:
(1984)
Deviations:
no
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): KY-ET
- Substance type: white powder
- Physical state: solid
- Stability in water: at least 96 h
- Storage condition of test material: at RT in the dark

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Sampling method: at t=0 and t=72 duplicate samples from test concentration and control
- Sample storage conditions before analysis: Not applicable (analyzed immediately)

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: supersaturated solution (10mg/L) achieved via 3 days magnetic stirring and filtration (5 µm)
- Controls: treated in the same manner as test substance solutions
- Evidence of undissolved material (e.g. precipitate, surface film, etc): prior to filtering larger undissolved test substance particles. The final test solution (after filtering) was clear and colourless.

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
TEST ORGANISM
- Common name: fresh water algae
- Strain: NIVA CHL 1
- Source (laboratory, culture collection): in-house laboratory culture
- Method of cultivation: growth medium M1 innoculated with algal cells from pure culture on agar; continuous light (6000-10000 lux) and aeration at 23 +/- 2 degrees C

ACCLIMATION
- Acclimation period: 3 days
- Culturing media and conditions (same as test or not): same as test
- Any deformed or abnormal cells observed: No

Study design

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

Test conditions

Hardness:
0.24 mmol/L (Ca+Mg)/ 24 mg CaCO3/L
Test temperature:
22.3-24.2 degrees C
pH:
8.1 - 8.3
Nominal and measured concentrations:
A supersaturated solution of 10mg/L was filtered through paper (5um) and this solution was used for the limit test. Subsequent analysis showed an initial concentration (@ t=0) of 0.072 mg/L and a final concentration (@ t=72h) of 0.005 mg/L, giving an average concentration of 0.019 mg/L. The limit of solubility in water of KY-ET is 0.002 mg/L.
Details on test conditions:
TEST SYSTEM
- Test vessel: 100 mL, glass
- Aeration: yes
- Initial cells density: 10^4 cells/mL
- Control end cells density: 48 x 10^4
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Milli-RO (reverse osmosis purified tap water)
- Culture medium different from test medium: M1 for culture, M2 for test

OTHER TEST CONDITIONS
- Sterile test conditions: no
- Adjustment of pH: no
- Photoperiod: Continuously
- Light intensity and quality: 6330-8555 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: counting chamber at start of test, followed by spectrophometric measurement at 720 nm at 24, 48 and 72h
Reference substance (positive control):
yes
Remarks:
potassium dichromate

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 0.019 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
0.019 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Details on results:
- Exponential growth in the control (for algal test): yes
In this limit test, no effects were observed at the tested concentration. Based on the overall average measured test concentration, the 72h-ErC50 value was determined to be higher than 0.019 mg/L and the 72h-NOEC value was determined to be 0.019 mg/L. Since these values exceed the maximum solubility of KY-ET in water (0.002 mg/L), it can be concluded that the 72h-EC50 value and teh 72h-NOEC value are above the maximum solubility in water of KY-ET.
Results with reference substance (positive control):
Results with reference substance are valid.
Under the conditions of the reference test, potassium dichromate inhibited cell growth at nominal concentrations of 1.0 mg/L and higher and reduced growth rate at 1.8 mg/L and higher. The EC50 for cell growth inhibition was 1.1 mg/L with a 95% confidence interval of 0.73 -1.8 mg/L, which was within the historical ranges for this test facility. The EC50 for growth rate reduction was 1.9 mg/L with a 95% confidence interval of 1.5 -2.4 mg/L, which was within the historical ranges for this facility.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
In this limit test, no effects were observed at the tested concentration. Based on the overall average measured test concentration, the 72h-ErC50 value was determined to be higher than 0.019 mg/L and the 72h-NOEC value was determined to be 0.019 mg/L. Since these values exceed the maximum solubility of KY-ET in water (0.002 mg/L), it can be concluded that the 72h-EC50 value and the 72h-NOEC value are above the maximum solubility in water of KY-ET.
Executive summary:

A limit tests was performed for KY-ET according to OECD 201 "Algae, Growth Inhibition Test". There were no deviations that would affect the results or data interpretation. No effects were observed at the tested concentration. Based on the overall average measured test concentration, the 72h-ErC50 value was determined to be higher than 0.019 mg/L and the 72h-NOEC was determined to be 0.019 mg/L. Since this exceeds the maximum solubility of KY-ET in water (0.002 mg/L), it can be concluded that the 72h-EC50 value and the 72h-NOEC are above the maximum solubility in water of KY-ET.