Life Power® L1

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:

2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study with GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

not specified

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

not specified

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.5400 (Algal Toxicity, Tiers I and II) (January 2012)

Deviations:

not specified

GLP compliance:

yes (incl. QA statement)

Test material

Reference

Name:

Unnamed

Type:

Constituent

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Samples were taken in plastic tubes, acidified with pure nitric acid, to keep them stable.

Test solutions

Vehicle:

no

Details on test solutions:

The test item is very poorly soluble in water. A test solution was prepared using a saturated solution method. A supersaturated test item stock solution (nominally 100 mg/L) was prepared by dispersing/dissolving the amount of test item into the test medium (OECD Medium) two days before the start of the study. This solution was shaken for about 24 hours at approximately 30°C and then was equilibrated for about 24 hours at the test temperature. The non-dissolved test material was removed by filtration through a fine (0.22 μm) filter to give the 100 % v/v saturated solution.

Test organisms

Test organisms (species):

Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)

Details on test organisms:

Species: Pseudokirchneriella subcapitata (formerly known as Selenastrum capricornutum)
Strain number: 61.81 SAG (identical strains: CCAP 278/4; UTEX 1648; ATCC 22662)
Source: The algae were supplied by the SAG: Collection of Algal Cultures, Inst. Plant Physiology, University of Göttingen, GERMANY. Cultured under standardised conditions (see OECD 201) in the Ecotoxicological Laboratory of CiToxLAB Hungary Ltd.
Initial cell number: The initial cell number in the test cultures was 10E4 cells/mL.
Pre-culturing: The pre-culture was intended to give an amount of alga suspension suitable for the inoculation of test cultures. The pre-culture was incubated under the conditions of the study in an aerated Algal Growth Medium and used when still exponentially growing (after an incubation period of 3 days). The cell count of above culture was determined by microscopic method and this cell suspension was diluted with Algal Growth Medium to 10E7 cells/mL.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Post exposure observation period:

None.

Test conditions

Test temperature:

22.8 – 23.1 °C in the flasks.

pH:

7.74 – 7.76 at the start and 8.92 – 9.16 at the end of the study.

Salinity:

Not applicable.

Nominal and measured concentrations:

A 100 % v/v saturated solution was tested.

Details on test conditions:

The exposure time was 72 hours. The test was started (0 hours) by inoculation of a biomass of approximately 10E4 algal cells per mL test medium.
The test was performed with six replicates per test concentration and six replicates in the control groups. Volumes of 100 mL algal suspension per replicate in 250 mL Erlenmeyer flasks were continuously shaken by a laboratory orbital shaker to keep algae in suspension. The flasks were covered with air-permeable stoppers.
Light Intensity: The algal culture flasks were continuously illuminated. The light intensity at the position occupied by algal culture flasks during the test was about 8114 lux (equivalent to 109 μE/m2/s), which was ensured with fluorescent lamps (with a spectral range of 400-700 nm).
A preliminary test was conducted to determine the approximate toxicity of the test item. Algal cells were exposed to at the solubility level of the test item in the test medium (100 % v/v saturated solution) plus controls, for 72 hours. The test was performed with two replicates per test concentration and three replicates in the control group.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 other: % v/v saturated solution

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks:

and also growth rate and yield.

Remarks on result:

other: A mean of 2.1 mg Li/L was detected in the test solutions.

Results with reference substance (positive control):

Result of the last study: EbC5072h = 0.70 mg/L.

Reported statistics and error estimates:

AVERAGE SPECIFIC GROWTH RATES: The results of the statistical evaluation (based on 2 Sample t-Test; α=0.05) show that the 0-72 h average specific growth rate was not statistically significantly different from the untreated control value, accordingly the No Observed Effect Concentration (NOEC) was determined as 100 % v/v saturated solution.
AREAS UNDER THE GROWTH CURVES: The results of the statistical evaluation (based on 2 Sample t-Test; α=0.05) show that the 0-72 h areas were not statistically significantly different from the untreated control value, accordingly the No Observed Effect Concentration (NOEC) was determined as 100 % v/v saturated solution.
YIELD: The results of the statistical evaluation (based on 2 Sample t-Test; α=0.05) show that the 0-72 h yield was not statistically significantly different from the untreated control value, accordingly the No Observed Effect Concentration (NOEC) was determined as 100 % v/v saturated solution.

Any other information on results incl. tables

VALIDITY: The cell density in the control cultures was increased by a factor of 66.33 within three days. The mean coefficient of variation for section-by-section specific growth rates (days 0-1; 1-2; 2-3) in the control cultures was 10.19 %. The coefficient of variation of average specific growth rates during the whole test period (day 0-3) in the control cultures was 0.59 %. All validity criteria were met, therefore the study can be considered as valid.

CONCENTRATION OF THE TEST ITEM: Analysis of test item formulations for Lithium concentration was performed. A concentration at saturation was tested in the experiment. The calculated geometric mean concentration was 2.1 mg Li/L.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Based on the results of this study, the test item had no toxic effect at saturation (2.1 mg Li/L, measured); the EC50 results and the LOEC are higher than the solubility level of the test item in the test medium.

Executive summary:

The effect of the test substance was assessed on algal growth using the unicellular green alga Pseudokirchneriella subcapitata (Selenastrum capricornutum), over an exposure period of 72 hours at the highest achievable concentrations of test item, according to OECD, EU and EPA methods.

Based on the results of this study, the test item had no toxic effect at saturation (2.1 mg Li/L, measured); the EC50 results and the LOEC are higher than the solubility level of the test item in the test medium.

EbC5072h = ErC5072h = EyC5072h >100 % v/v saturated solution (2.1 mg Li/L).

NOEC = 100 % v/v saturated solution (2.1 mg Li/L).