Ammonium iodide

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

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:

guideline study

Justification for type of information:

Experimental test result performed using standard OECD test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

The stock solution 100 mg/l was prepared by dissolving test chemical in OECD growth medium.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Strain: 86.81 SAG
- Source (laboratory, culture collection): Institute of botany of the ASCR
- Initial biomass concentration: 5x10(3) cells /ml
- Method of cultivation: No data available

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test temperature:

23±2°C

pH:

without adjustment
the sample at concentration: 100 mg/l: pH 7.7 changed to pH 7.6 during the test
control: pH = 8.0 changed to pH = 7.7 during the test

Nominal and measured concentrations:

Nominal test chemical conc. used for the study was 100 mg/l.

Details on test conditions:

TEST SYSTEM
- Test vessel: 50 ml Glass vessel
- Type (delete if not applicable): closed (with air permeable stopper)
- Sample volume: 15 ml
- Initial cells density: 5000 cells/ml
- No. of vessels per concentration (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: Continuous
- Light intensity and quality: 6000-8000 lx

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: electronic particle counter.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate (K2Cr2O7)

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: p = 0.056

Results with reference substance (positive control):

- Results with reference substance valid
- EC50: 0.77 mg/L (24 hours)

Reported statistics and error estimates:

The differences in means of control and sample were estimated by the t-test for independent groups at a 95 % confidence level, all individual replicates were used (STATISTICA CZ – data analysis software system, version 9.0, StatSoft, Inc.). Statistically significant differences are for p < 0.05.

Result of a limit test at sample concentration 100 mg/l:

Sample	Sample Information	Conc. (mg/l)	µ (d-1)	CV (%)	I%	Statistics
						p	Significant difference
Control	OECD medium	0	1.85	0.9	-	0.056	No
Test system	Test chemical	100	1.83	0.7	1.1

Validity criteria fulfilled:

yes

Conclusions:

Based on the growth rate inhibition of algae Desmodesmus subspicatus (previous name: Scenedesmus subspicatus) due to the exposure of test chemical, the 72hr Inhibition percentage (I%) value was determined to be 1.1% at 100.0 mg/l of test concentration. Thus, the 72 hr median effect conentration (EC50) was evaluated to be > 100 mg/l.

Executive summary:

An acute test was conducted for 72 hrs for assessing the effect of test chemical on green algae. The test was performed in accordance to OECD Guideline 201 (Alga, Growth Inhibition Test). Desmodesmus subspicatus (previous name: Scenedesmus subspicatus) of strain 86.81 SAG obtained from Institute of botany of the ASCR with an initial biomass conc. 5000 cells /ml was used as a test organism for the study. The solution 100 mg/l was prepared by dissolving test chemical in OECD growth medium. Nominal test chemical conc. used for the study was 100 mg/l, i.e, limit test was conducted. Study was performed using Desmodesmus subspicatus as a test organism in a static system. Desmodesmus subspicatus were exposed to test chemical in 50 ml glass vessel in a volume of 15 ml of liquid solution containing both the chemical and media. The beakers were placed in a room at a temperature of 23±2°C with a continuous light intensity of 6000-8000 lx, respectively. Alongwith the test chemical, one positive control Potassium dichromate (K2Cr2O7) and control containing OECD medium without test chemical were also run simultaneously. Cell counting was carried out using electronic particle counter. The differences in means of control and sample were estimated by the t-test for independent groups at a 95 % confidence level, all individual replicates were used (STATISTICA CZ – data analysis software system, version 9.0, StatSoft, Inc.). Statistically significant differences are for p < 0.05. On the basis of the effect of test chemical on the growth rate of the test organism Desmodesmus subspicatus, the 72hr Inhibition percentage (I%) value was determined to be 1.1% at 100.0 mg/l of test chemical concentration. Thus, the 72 hr median effect concentration (EC50) was evaluated to be > 100 mg/l., indicating that the test chemical is non-toxic to aquatic algae and therefore considered to be 'not classified' as per the CLP classification criteria.

Description of key information

An acute test was conducted for 72 hrs for assessing the effect of test chemical on green algae (Experimental study report, 2018). The test was performed in accordance to OECD Guideline 201 (Alga, Growth Inhibition Test). Desmodesmus subspicatus (previous name: Scenedesmus subspicatus) of strain 86.81 SAG obtained from Institute of botany of the ASCR with an initial biomass conc. 5000 cells /ml was used as a test organism for the study. The solution 100 mg/l was prepared by dissolving test chemical in OECD growth medium. Nominal test chemical conc. used for the study was 100 mg/l, i.e, limit test was conducted. Study was performed using Desmodesmus subspicatus as a test organism in a static system. Desmodesmus subspicatus were exposed to test chemical in 50 ml glass vessel in a volume of 15 ml of liquid solution containing both the chemical and media. The beakers were placed in a room at a temperature of 23±2°C with a continuous light intensity of 6000-8000 lx, respectively. Alongwith the test chemical, one positive control Potassium dichromate (K2Cr2O7) and control containing OECD medium without test chemical were also run simultaneously. Cell counting was carried out using electronic particle counter. The differences in means of control and sample were estimated by the t-test for independent groups at a 95 % confidence level, all individual replicates were used (STATISTICA CZ – data analysis software system, version 9.0, StatSoft, Inc.). Statistically significant differences are for p < 0.05. On the basis of the effect of test chemical on the growth rate of the test organism Desmodesmus subspicatus, the 72hr Inhibition percentage (I%) value was determined to be 1.1% at 100.0 mg/l of test chemical concentration. Thus, the 72 hr median effect concentration (EC50) was evaluated to be > 100 mg/l., indicating that the test chemical is non-toxic to aquatic algae and therefore considered to be 'not classified' as per the CLP classification criteria.

Additional information

An acute test was conducted for 72 hrs for assessing the effect of test chemical on green algae (Experimental study report, 2018). The test was performed in accordance to OECD Guideline 201 (Alga, Growth Inhibition Test). Desmodesmus subspicatus (previous name: Scenedesmus subspicatus) of strain 86.81 SAG obtained from Institute of botany of the ASCR with an initial biomass conc. 5000 cells /ml was used as a test organism for the study. The solution 100 mg/l was prepared by dissolving test chemical in OECD growth medium. Nominal test chemical conc. used for the study was 100 mg/l, i.e, limit test was conducted. Study was performed using Desmodesmus subspicatus as a test organism in a static system. Desmodesmus subspicatus were exposed to test chemical in 50 ml glass vessel in a volume of 15 ml of liquid solution containing both the chemical and media. The beakers were placed in a room at a temperature of 23±2°C with a continuous light intensity of 6000-8000 lx, respectively. Alongwith the test chemical, one positive control Potassium dichromate (K2Cr2O7) and control containing OECD medium without test chemical were also run simultaneously. Cell counting was carried out using electronic particle counter. The differences in means of control and sample were estimated by the t-test for independent groups at a 95 % confidence level, all individual replicates were used (STATISTICA CZ – data analysis software system, version 9.0, StatSoft, Inc.). Statistically significant differences are for p < 0.05. On the basis of the effect of test chemical on the growth rate of the test organism Desmodesmus subspicatus, the 72hr Inhibition percentage (I%) value was determined to be 1.1% at 100.0 mg/l of test chemical concentration. Thus, the 72 hr median effect concentration (EC50) was evaluated to be > 100 mg/l., indicating that the test chemical is non-toxic to aquatic algae and therefore considered to be 'not classified' as per the CLP classification criteria.