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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:
1 April 2003 - 4 April 2003
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study has been performed according to OECD and/or EC guidelines and according to GLP principles.

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)
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-MA
- Substance type: white to light pink 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 (10 mg/L) achieved via 4 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

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:
22.7-24.2 degrees C
pH:
8.0 - 8.5
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 0.015 mg/L and a final concentration (@ t=72h) of 0.004 mg/L, giving an average concentration of 0.008 mg/L. The limit of solubility of KY-MA in water is 0.006 mg/L.
Details on test conditions:
TEST SYSTEM
- Test vessel: 100 mL, glass
- Initial cells density: 10^4 cells/mL
- Control end cells density: 44.8 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: 24/7
- 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.:
> 0.008 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.:
0.008 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
There were no effects seen in the limit test. A 10 mg/L supersaturated solution was filtered through paper (5um). This solution was then used (6 replicates) in the limit test. Analysis showed that the actual starting concentration of KY-MA in the solutions was 0.015 and the actual final concentration was 0.004, giving an average concentration of ~0.008 mg/L. The limit of solubility for KY-MAin water is 0.006 mg/L, thusit can be concluded that the 72h-EC50 value and the 73h-NOEC value are above the maximum solubility in water of KY-MA.
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 0.008 mg/L and the 72h-NOEC value was determined to be 0.008 mg/L. Since these values 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 value are above the maximum solubility in water of KY-ET.
Executive summary:

A limit test was performed for KY-MA according to OECD 201 "Algae, Growth Inhibition Test". There were no deviations that would affect the results or data interpretation. A 10 mg/L supersaturated solution was filtered through paper (5um). This solution was then used (6 replicates) in the limit test. Analysis showed that the actual starting concentration of KY-MA in the solutions was 0.015 and the actual final concentration was 0.004, giving an average concentration of ~0.008 mg/L. Since no inhibition was observed, the 72h-EC50 value is higher than 0.008 mg/L and the 72h-NOEC is 0.008 mg/L. The limit of solubility for KY-MA in water is 0.006 mg/L, thus it can be concluded that the 72h-EC50 and the 72h-NOEC value are above the maximum solubility in water of KY-MA.