Manganate(1-), glycinato-N,O)[sulfato(2-)-O]-, hydrogen

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

- Principle of test: Metal toxicity test were performed in Nitzschia closterium W.Sm.with two different media: chelating and non-chelating.The liquid growth medium as previously described constituted the non-chelating medium. In order to determine the effects of chelation on metal toxicity a chelating medium was prepared by modification of the non-chelating medium with the addition of 0.1% by volume of a 1.0%-citric acid solution and 0.1% by volume of NCTC-135 tissue culture medium (Grand Island Biological Co.) which contained amino acids capable of chelating various divalent cations and also supplied various B complex vitamins and D-glucose to the chelating medium. The algae were exposed to the metals, which resulted from dissolution of the respective sulfate salt in one of the media, for 96h. The number of cells per mL was counted (100x power of a compound microscope) using a bright line hemocytometer (American Optical Co.). Cell counts were made at the start and at 24, 48, 72 and 96 hr.
- Short description of test conditions: Both the chelating and non-chelating media have a specific gravity of 1.024. The chelating medium has a pH of 6.7-6.9, while the non-chelatin.g medium has a pH of 8.0-8.1.The algal stock was maintained in cultures in liquid medium containing one liter of filtered Aquarium Systems Instant Ocean Sea Water to which was added 0.1 g Ca(NO3)2-4H2O, 0.02 g K2HPO4 and 0.05g NaSiO3. Stock cultures as well as all experimental runs were maintained under the same light and temperature regimen: at 15.5 ± 0.5 °C and a photocycle of 16h light (5 Klux) and 8h dark. All toxicity tests were performed in sterile 100 x 13 mm pyrex test tubes containing exactly 3.0 mL of test solution in which were suspended from 1.4E+05 - 2E+05 diatoms per mL with an average of 1.9E+05 cells per mL. These tubes were stoppered with porous soft rubber plugs.
- Parameters analysed / observed: cell growth

GLP compliance:

no

Remarks:

The study was conducted prior to implementation of GLP and OECD guidelines

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Depending on the final test concentrations of metal used, an appropriate stock concentration was prepared such that after several aseptic serial dilutions, using sterile deionized water, the final test concentration could be added as 0.1 mL of metal solution to 2.9 mL of appropriate medium and diatoms in the pyrex test tube.

Test organisms (species):

Nitzschia sp.

Details on test organisms:

TEST ORGANISM
- Common name: brown alga
- Strain: Nitzschia closterium
- Source (laboratory, culture collection): was isolated in pure culture from net plankton samples taken in the western end of Long Island Sound near the Orchard Beach region of Pelham Bay New York.
- Age of inoculum (at test initiation):
- Method of cultivation: Pure cultures were established by serial and replicate streaking of the phytoplankton on 3% agar in sterile sea water in sterile Petri plates. These plates were then incubated for 20-30 days in a Sherer-Gillet R1-24 LTP growth chamber at a constant temperature of 15.5 ± 0.5 C under a light program of 16 hr light (5 Klux) and 8 hr dark. Once the test species was isolated it was maintained in stock cultures in liquid medium containing one liter of filtered Aquarium Systems Instant Ocean Sea Water to which was added 0.1 g Ca(NO3)2-4H2O, 0.02 g K2HPO4 and 0.05g NaSiO3.

ACCLIMATION
- Culturing media and conditions (same as test or not):yes

Test type:

semi-static

Water media type:

saltwater

Limit test:

no

Total exposure duration:

96 h

Nominal and measured concentrations:

0.0, 10.0, 18.0, 24.0, 32.0, 42.0, 56.0 ppm nominal in non-chelating medium

Key result

Duration:

96 h

Dose descriptor:

EC50

Remarks:

non-chelating medium

Effect conc.:

25.7 mg/L

Nominal / measured:

nominal

Conc. based on:

other: Mn2+

Basis for effect:

growth rate

Key result

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

53.8 mg/L

Nominal / measured:

nominal

Conc. based on:

other: Mn2+

Basis for effect:

growth rate

Reported statistics and error estimates:

The data for each metal were pooled and the resulting data were treated according to the statistical methods of probit analysis (Finney 1964).

Validity criteria fulfilled:

not applicable

Conclusions:

In the present study of Roslo and Rachin (1975) the diatom Nitzschia closterium were exposed to manganese resulting from the dissolution of manganese sulfate in water, for 96h in saltwater under semi-static conditions in a concentration range between 10 and 100 mg/L. The EC50 was determined to be 25.7 mg Mn2+/L for the non-chelating medium. The algae were also incubated with a chelating medium under the same condictions. The chelating medium contained amino acids which diminished the toxic effect for about 50%. With the chelating medium the EC50 of manganese was 53.8 mg/L.

Executive summary:

In a 96 hour toxicity study cultures of Nitzschia closterium were exposed to MnSO₄in a concentration range between 10 and 100 mg/L in salt water, under semi-static conditions.

The algae were exposed to the metals, which resulted from dissolution of the respective sulfate salt in one of the media, for 96h. The number of cells per mL was counted (100x power of a compound microscope) using a bright line hemocytometer (American Optical Co.). Cell counts were made at the start and at 24, 48, 72 and 96 hr. The algal stock was maintained in cultures in liquid medium containing one liter of filtered Aquarium Systems Instant Ocean Sea Water to which was added 0.1 g Ca(NO3)2-4H2O, 0.02 g K2HPO4 and 0.05g NaSiO3. Stock cultures as well as all experimental runs were maintained under the same light and temperature regimen: at 15.5 ±0.5 °C and a photocycle of 16h light (5 Klux) and 8h dark. All toxicity tests were performed in sterile 100 x 13 mm pyrex test tubes containing exactly 3.0 mL of test solution in which were suspended from 1.4E+05 - 2E+05 diatoms per mL with an average of 1.9E+05 cells per mL. These tubes were stoppered with porous soft rubber plugs.

 The study was conducted prior to implementation of GLP and OECD guidelines.

This toxicity study is classified as acceptable and was conducted according to accepted scientific methods for algal growth inhibition in Nitzschia closterium.

 

Results Synopsis

Test Organism: Nitzschia closterium

Test Type: Semi-static

 

96 hr EC50: 27.5 mg Mn²⁺/L, corresponding to 113.2 mg manganese monoglycinate sulfate/L.

Endpoint(s) Effected: growth rate

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

1. SOFTWARE

ECOSAR v 1.11
2. MODEL (incl. version number)

ECOSAR v 1.11; The ECOSAR (ECOlogical Structure Activity Relationship) Class Programm for Microsoft Windows; U.S. Environmental Protection Agency; Office of Chemical Safety and Pollution Prevention (Kelly Mayo-Bean, June 19, 2012)
3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL

CAS: 56-40-6
4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
For more detailed information please refer to the 'attached justification' section
5. APPLICABILITY DOMAIN
For more detailed information please refer to the 'attached justification' section
6. ADEQUACY OF THE RESULT
For more detailed information please refer to the 'attached justification' section

Qualifier:

no guideline followed

Principles of method if other than guideline:

QSAR prediction of dose descriptors using EPISuite ™, The ECOSAR (ECOlogical Structure Activity Relationship) Class Programm for Microsoft Windows; U.S. Environmental Protection Agency; Office of Chemical Safety and Pollution Prevention (Kelly Mayo-Bean, June 19, 2012).

GLP compliance:

no

Key result

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

93 748.48 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other:

Remarks:

Results obtained from QSAR calculation

Validity criteria fulfilled:

not applicable

Conclusions:

In the present QSAR prediction which was conducted using EPISuite ™, The ECOSAR (ECOlogical Structure Activity Relationship) Class Programm for Microsoft Windows; U.S. Environmental Protection Agency; Office of Chemical Safety and Pollution Prevention (Kelly Mayo-Bean, June 19, 2012) for glycine, the estiamted LC50 value for glycine was reported to be 93748.48 mg/L. The prediction is reliable because the substance falls in the applicability domain of the model. Moreover, cut-off values that limit the predictions reliability were not exceeded. Based on the presented results glycine does not need to be classified according to Regulation (EC) No 1272/2008 (CLP) and the Globally Harmonized System for Classification and Labelling of Chemicals (GHS).

Executive summary:

The LC50 value for glycine was predicted with EPISuite ™, The ECOSAR (ECOlogical Structure Activity Relationship) Class Programm for Microsoft Windows; U.S. Environmental Protection Agency; Office of Chemical Safety and Pollution Prevention (Kelly Mayo-Bean, June 19, 2012). Based on the chemical structure of glycine which reveals functional groups that are present in the training data sets of the model used, the substance is considered to fall in the applicability domain of ECOSAR. The LC50 value predicted for L-glycine is far above the 100 mg/L limit concentration. (93748.48 mg/L) and are more than 10 -fold higher than the water solubility. Thus, no toxic effects are expected to occur up to saturation limits. Based on these information glycine is considered to exhibit a very low toxicity to aquatic invertebrates.

Reference 3

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Principles of method if other than guideline:

- Principle of test: Scenedesmus quadricauda were exposed to different metal ions resulting from dissolving the respective metal salt. The algae were statically cultivated dining the tests in 500 mL Erlenmeyer flasks with 200 mL cultivation medium supplemented with individual metals in ten various concentrations, plus the control. The EC50 values and their 95 % confidence intervals were estimated by probit analysis (Stephan, 1977) and expressed chronic effect of tested metals. The alga were exposed for 12 days.
- Short description of test conditions: Each metal concentration as well as control was tested in triplicate. For inoculation, algae in the exponential phase of the growth were used and the total inoculum in test and control media was 25,000 coenobia (four cells connected in one unit). Then, growth rate inhibition by calculating coenobia number in hemocytometer was determined, respiratory rate by using the oxygen electrode cormected with computer was measured (Fargasova and Drtil, 1996) and total chlorophyll, chlorophyll a and chlorophyll b contents by using a spectrophotometric method were determined (Fargasova, 1996). Before respirometric measurement the cultures were aerated by nitrogen to decrease oxygen amount to the level 2 - 3 mg/L.
- Parameters analysed / observed: total chlorophyll, chlorophyll a and chlorophyll b as well as growth inhibition.

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

not specified

Details on test solutions:

Test solution preparation was not reported

Test organisms (species):

Scenedesmus quadricauda

Details on test organisms:

TEST ORGANISM
- Common name: green alga
- Strain: Scenedesmus quadricauda
- Source (laboratory, culture collection): Institute of Botany AS CR, Trebon, Czech Republic
- Method of cultivation:The culture was maintained under constant temperature (25 ± 1°C) and permanent light conditions (2,000 lux).

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

12 d

Dissolved oxygen:

Before respirometric measurement the cultures were aerated by nitrogen to decrease oxygen amount to the level 2 - 3 mg/L.

Nominal and measured concentrations:

Not reported

Details on test conditions:

TEST SYSTEM
- Test vessel:Erlenmeyer flasks
- Material, size, headspace, fill volume: Erlenmeyer flasks 500 mL fill volume, 200 mL test volume
- No. of vessels per concentration (replicates): triplicates
- No. of vessels per control (replicates): triplicates
- Initial cells density: For inoculation, algae in the exponential phase of the growth were used and the total inocultun in test and control media was 25,000 coenobia (four cells comiected in one unit).

GROWTH MEDIUM
- Standard medium used: not specified, modified Knopp solution without calcium


OTHER TEST CONDITIONS
- Photoperiod: permanent light conditions
- Light intensity and quality:2000 lux


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: hemocytometer; spectrophotometer;
- Chlorophyll measurement: total chlorophyll, chlorophyll a and chlorophyll b contents by using a spectrophotometric method

Reference substance (positive control):

not specified

Key result

Duration:

12 d

Dose descriptor:

EC50

Effect conc.:

4.98 mg/L

Nominal / measured:

nominal

Conc. based on:

other: Mn2+

Basis for effect:

growth rate

Reported statistics and error estimates:

The EC50 values and their 95 % confidence intervals were estimated by probit analysis (Stephan, 1977) and expressed chronic effect of tested metals.

Validity criteria fulfilled:

not applicable

Conclusions:

In the present study of Fargasova et al. (1999) Scenedesmus quadricauda were exposed to different concentrations of MnSO4 x H2O for 12 days under static condictions. The 12 days EC50 value was 4.98 mg/L for Mn2+ ions determined with a probit analysis.

Executive summary:

In a 12 days toxicity study cultures of Scenedesmus quadricauda were exposed to MnSO₄ in different concentrations under static conditions. Growth rate inhibition by calculating coenobia number in hemocytometer was determined, respiratory rate by using the oxygen electrode cormected with computer was measured and total chlorophyll, chlorophyll a and chlorophyll b contents by using a spectrophotometric method were determined.Before respirometric measurement the cultures were aerated by nitrogen to decrease oxygen amount to the level 2 - 3 mg/L.

The 12 days EC50 value was 4.98 mg/L for Mn²⁺ ions determined with a probit analysis.

 

This toxicity study is classified as acceptable and was conducted according scientifically accepted methods for the algal growth inhibition in Scenedesmus quadricauda.

 

Results Synopsis

Test Organism: Scenedesmus quadricauda

Test Type: Static

 

12 d EC50: 4.98 mg Mn²⁺/L corresponding to 20.5 mg manganese monoglycinate sulfate/L.

Endpoint(s) Effected:  growth rate

Reference 4

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Qualifier:

according to guideline

Guideline:

other: Environment Canada, "Biological Test Method: Toxicity Test using the Freshwater Alga Selenastrum capricornutum", Environ. Prot. Serv., Environment Canada Report EPS 1/RM/25, 1992

Principles of method if other than guideline:

- Principle of test: A small volume test solution was inoculated with a known number of Selenastrum capricornutum freshwater algal cells and incubated for 72h. At the conclusion of the test, growth of the algae in the test concentrations are compared with algae growth in the controls. A LC50 and an IC50 value was calculated.
- Short description of test conditions: Water Quality Criteria-control dilution water: pH 6.0 - 8.5, Teperature: 24 ± 2°C, each test was run with a set of five concentrations plus control, water hardness was controlled and the actual test agent concetration was determined at day 1
- Parameters analysed / observed: growth, cell mass

GLP compliance:

not specified

Analytical monitoring:

not specified

Vehicle:

not specified

Details on test solutions:

not reported

Test organisms (species):

Selenastrum sp.

Details on test organisms:

TEST ORGANISM
- Common name: green algae
- Strain: Selenastrum capricornutum
- Source (laboratory, culture collection): University of Toronto Botany Department
- Age of inoculum (at test initiation): 4 to 7 day old culture

Test type:

not specified

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Hardness:

100 mg/L CaCO3

Test temperature:

24 ± 2°C

pH:

6.0 to 8.5

Nominal and measured concentrations:

not reported

Details on test conditions:

No further information about the test conditions were reported

Reference substance (positive control):

not specified

Key result

Duration:

72 h

Dose descriptor:

IC50

Effect conc.:

8.29 mg/L

Nominal / measured:

nominal

Conc. based on:

other: Mn2+

Basis for effect:

growth rate

Validity criteria fulfilled:

not applicable

Conclusions:

In the present publication the effect of manganese chloride was investigated in order to establish freshwater guidelines for the protection of aquatic life in British Columbia. Freshwater algae Selenastrum capricornutum were incubated with at least five concentrations of dissolved manganese chloride for 72h at 24 °C, the IC50 value was calculated to be 8.29 mg Mn2+/L.

Executive summary:

In a 72 hour toxicity study cultures of Selenastrum capricornutum were exposed to MnCl₂at at least five concentrations. The temperature of the test was 24 ± 2°C, the hardness was controlled at 100 mg/L CaCO₃. The test was conducted to establish freshwater guidelines for the protection of aquatic life in British Columbia. The calculated IC50 for the growth rate was reported.

 

This toxicity study is classified as acceptable and was performed according to accepted scientific principles for the algal growth inhibition test in Selenastrum capricornutum.

 

Results Synopsis

Test Organism: Selenastrum capricornutum

Test Type: n/a

 

72 hr IC50: 8.29 mg Mn²⁺/L corresponding to 34.1 mg manganese monoglycinate sulfate/L.

Endpoint(s) Effected:  growth rate

Description of key information

- the cell growth of Nitzschia closterium in the presence of different metal ion concentrations (Rosko and Rachlin, 1975). The medium in which the algea were incubated was either chelating or non-chelating. The algae were incubated with different concentrations of MnSO4 under semi-static conditions for 96h in saltwater.The determined EC50 value was 25.7 mg/L for the non-chelating medium and 53.8 mg/L for the chelating medium. Read-across.

- Scenedesmus quadricauda were exposed to different metal ions (i.a. MnSO4) under static conditions for 12 days (Fargasova et al., 1999). The EC50 value was obtained by measuuring the cell growth inhibition, total chlorophyll, chlorophyll a and chlorophyll b concentrations. The EC50 was determined to be 4.98 mg/L Mn2 +. Read-across.

- Selenastrum capricornutum were incubated with MnCl2 in five concentration of dissolved MnCl2 for 72h and the IC50 value was calculated to be 8.29 mg/L Mn2 +. Read-across.

- QSAR estimation using ECOSAR v 1.11 was performed for glycine and provided an EC50 value of 93748.48 mg/L. Read-across.

Key value for chemical safety assessment

EC50 for freshwater algae:

34.1 mg/L

Additional information

There are no data for toxicity to aquatic algae and cyanobacteria of manganese monoglycinate sulfate. However based on the read-across hypothesis that the target substance manganese monoglycinate sulfate hydrolyses when dissolved in aqueous solutions, the organisms, i.e. algae and cyanobacteria are mainly exposed to the single constituents of the target substance, namely glycine, Mn²⁺and SO₄^2-.

Data are available for MnSO₄and MnCL₂as well as for the amino acid glycine.

The effect level for toxicity to aquatic algae and cyanobacteria of glycine were predicted with ECOSAR. Since glycine is exhibits common functional groups that are present in the respective training data set and glycine exhibits a rather small molecular weight (75 g/mol) it falls in the applicability domain of the QSAR model. The value predicted is more than 10-fold higher than glycine’s water solubility (93748.48 mg/L) thus, glycine is not expected to cause any toxic effect up to the saturation limit. Based on this information glycine is not considered to participated to the effect level of the target substance managanese monoglycinate sulfate.

In the study of Rachlin and Rosko (1975) the cell growth of Nitzschia closterium in the presence of different metal ion concentrations was determined. The medium in which the algae were incubated was either chelating or non-chelating. The algae were incubated with different concentrations of MnSO₄under semi-static conditions for 96h in saltwater. The determined EC50 value was 25.7 mg Mn²⁺/L for the non-chelating medium and 53.8 mg Mn²⁺/L for the chelating medium.

In another study of Fargasova (1999) Scenedesmus quadricauda were exposed to different metal ions (i.a. MnSO₄) under static conditions for 12 days. The EC50 value was obtained by measuuring the cell growth inhibition, total chlorophyll, chlorophyll a and chlorophyll b concentrations. The EC50 was determined to be 4.98 mg/L Mn²⁺.

Finally, in the study of Reimer (1999) which was preformed to establish a guideline for freshwater protection, Selenastrum capricornutum were incubated with MnCl₂in five concentration of dissolved MnCl₂for 72h and the IC50 value was calculated to be 8.29 mg/L Mn²⁺.

Based on the available information the Mn²⁺ion determines the toxicity to aquatic algae and cyanobacteria. Of the presented studies only two were conducted with the recommended green algae species which is considered to be the most sensitive species. In the study of Fargasova et al. the EC50 value was determined after 12days, thus, based on the shorter duration, the IC50 value Reimer (1999) is considered the most reliable and restrictive value. The 72 h IC50 for Mn²⁺ions in Selenastrum capricornutum is 8.29 mg/L which corresponds to approximately 34.1 mg manganese monoglycinate sulfate/L.