Lithium iodide

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:

From 28 june 2022 to 29 july 2022

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2022

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Version / remarks:

Pseudokirchneriella subcapitata is a freshwater green algae that is
recommended by the OECD Guideline 201.

Deviations:

yes

Remarks:

A deviation was written for the storage of reference items. There is no impact on the study and on the acquired data

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Lithium iodide

EC Number:

233-822-5

EC Name:

Lithium iodide

Cas Number:

10377-51-2

Molecular formula:

ILi

IUPAC Name:

lithium iodide

Test material form:

solid

Specific details on test material used for the study:

Batch number 20F264105

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

The test item quantification was performed according to the validated analytical method to measure the concentration of test item at 0 and 72 hours in all test item concentrations.
The analytical samples were taken at the beginning of the test in the test solutions preparations and at
the end of the test in the content of the vessels pooled by replicate.
For all samples:
- Collect and filter around 1.5 mL with Xtra RC-20/13 into a 1.5 mL glass vial.
- Store samples on the sampler of the analytical instrument before analysis (room temperature).

Test solutions

Vehicle:

no

Details on test solutions:

Test has been performed under static conditions. The test solutions were prepared at the beginning of
the test, by dilution of a primary stock solution.

Stock solution preparation (SS)

Date of preparation : 27/06/2022
Actual amount of test item weighed (mg) :50.3
Medium final volume (mL) : 500
Finalconcentration (mg.L-1) : 100.6
Internal number: SM1_ecotox_22_0150

Test organisms

Test organisms (species):

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

Details on test organisms:

The Pseudokirchneriella subcapitata stock culture will be supplied on sloped agar tubes prepared from a strain of liquid algae supplied by the CCAP (Strain CCAP 278/4. Culture Collection of Algae and Protozoa. UK).
A preculture (liquid) will be prepared in fresh medium used during test (OECD medium) and regularly transferred to fresh medium. The precultures will be incubated at a temperature in the range of 21 to 24°C. controlled at ± 2°C with continuous illumination and transferred twice a week. The algae used during the test will be in an exponential growth phase. To ensure that the algae is in the exponential growth phase when used to inoculate the test solutions. an inoculum culture in the test medium will be prepared 2-4 days before start of the test.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

Temperature: at a temperature in the range of 18.3 to 24°C, One measurement at 18.5°C and one at 23.9°C, the test began after the temperature has been lowered
at the right temperature (22°C) approximately at 11:30 am and the temperature sensor was incorrectly
placed in the growth chamber, against the wall where an air flow is going which is not representative of
the exposure temperature. The temperature sensor was replaced so no deviation was written.

pH:

pH at t0h = 8.1
pH at t72h = 7.7

The pH did not vary by more than 1.5 during the test.

Nominal and measured concentrations:

Since the deviation between the measured concentrations and the nominal concentrations was within
the range of ± 20 %, analysis of the results was based in the nominal concentrations.
QC measures are the same for T0 samples and T72h samples. The range for the QC is 90-110 %, so
QC are valid and sequences are compliant.

Details on test conditions:

Based on the results of the non-GLP range-finder, the test solutions were prepared in OECD medium at the definitive theorical concentrations.
A control was performed at the same time with test media only.
Every flask was inoculated with the initial cell concentration of 5*103 cells.mL-1 of Pseudokirchneriella subcapitata as recommended in the guideline OECD 201.
Starting from a culture of 2.879E+06 cells per millilitres, 868.4 μL were inoculated in 500 mL of OECD medium for the control (C05) and 434.2 μL were inoculated in 250 mL of OECD medium for the tested concentrations (C06 to C10), to reach a concentration of about 5000 cells per milliliters. The preparations were divided in 6 replicates for the control and 3 replicates for the tested concentrations consisting in about 80 mL per replicates.
The flasks consisted of glass Erlemeyer flasks of 250 mL capacity, closed with air-permeable stoppers made of polyether foam.
The test was performed in a thermostatic chamber maintained in the range of 21°C to 24°C controlled to ± 2°C under continuous illumination (with a light intensity between 4440 and 8880 lux) . Algae were maintained suspended under continuous orbital stirring.
According to the study plan, cell biomass was measured every day in each flask using an electronic particle counter.

Reference substance (positive control):

yes

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

72 h

Dose descriptor:

EC10

Remarks:

(95% confidence limits)

Effect conc.:

ca. 57.4 mg/L

95% CI:

>= 40.7 - <= 85.5

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Key result

Duration:

72 h

Dose descriptor:

EC20

Remarks:

(95% confidence limits)

Effect conc.:

ca. 83.9 mg/L

95% CI:

>= 70.4 - <= 96.4

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 3

Key result

Duration:

72 h

Dose descriptor:

EC50

Remarks:

(95% confidence limits)

Effect conc.:

>= 100 mg/L

95% CI:

>= 100

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 4

Key result

Duration:

72 h

Dose descriptor:

EC10

Remarks:

(95% confidence limits)

Effect conc.:

ca. 24.2 mg/L

95% CI:

>= 7.2 - <= 55.6

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

yield

Effect concentrations 5

Key result

Duration:

72 h

Dose descriptor:

EC20

Remarks:

(95% confidence limits)

Effect conc.:

ca. 33.6 mg/L

95% CI:

>= 13.8 - <= 64.8

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

yield

Effect concentrations 6

Key result

Duration:

72 h

Dose descriptor:

EC50

Remarks:

(95% confidence limits)

Effect conc.:

ca. 58.5 mg/L

95% CI:

>= 37.8 - <= 88.8

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

yield

Effect concentrations 7

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

ca. 31.27 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 8

Key result

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

ca. 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 9

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

ca. 31.27 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

yield

Effect concentrations 10

Key result

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

ca. 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

yield

Details on results:

The effects of test item the definitive theoretical concentrations of 0; 0.95; 3.05; 9.77; 31.25 and 100.0
mg test item.L-1 to Pseudokirchneriella subcapitata were investigated under static conditions.
According to the results of the test. the NOErC and the NOEyC were both observed to be at 100.0 mg/L
(nominal).
The analytical samples were taken at the beginning of the test and at the end of the test (72 hours) with
the content of the vessels pooled and homogenized.
Since the deviation between the measured concentrations and the nominal concentrations was within
the range of ± 20 %, analysis of the results was based in the nominal concentrations.

Results with reference substance (positive control):

Results with positive control are conformed.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The objective of this study was to assess the effects of test item “Lithium iodide anhydrous” on the
growth of Pseudokirchneriella subcapitata over a period of 72 hours according to OECD 201 Guideline
(March 2006, corrected July 2011). Pseudokirchneriella subcapitata is a freshwater green algae that is
recommended by the OECD Guideline 201.
The effects of test item the definitive theoretical concentrations of 0; 0.95; 3.05; 9.77; 31.25 and 100.0
mg test item.L-1 to Pseudokirchneriella subcapitata were investigated under static conditions.

The analytical samples were taken at the beginning of the test and at the end of the test (72 hours) with
the content of the vessels pooled and homogenized.
Since the deviation between the measured concentrations and the nominal concentrations was within
the range of ± 20 %, analysis of the results was based in the nominal concentrations.
ErC50 -72h > 100 mg/L
EyC50 -72h = 58.5 mg/L
NOEC growth rate = 31.27 mg/L
LOEC growth rate = 100 mg/L