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

Endpoint summary

Description of key information

Short-term toxicity to aquatic invertebrates:

Biesinger and Christensen (1972): water flea (Daphnia magna) were exposed to concentrations of 5 and 10 mg/L MnCl₂for 48 h under static conditions. The LC50 was determined to be 9.8 mg Mn²⁺/L. read-across

Martin and Holdich (1985): The toxicity of metal ions in Asellus aquaticus and Crangonyx pseudogracilils was determined after 48h and 96h under static conditions in at least 8 Mn²⁺concentrations. The 48h LC50 was determined as follows: 1389 ppm Mn²⁺for Crangonyx pseudogracilils and the 96h LC50 was 694 ppm Mn²⁺for Crangonyx pseudogracilils. read-across

Sorvani and Sillanpää (1996): The 24h LC50 values of free divalent Manganese ions and the respective EDTA/DTPA complex were determined in Daphnia magna. After 24h the EC50 value was 56 mg Mn²⁺/L for the free ions and increased for the respective EDTA complex (940 mg/L) and for the DTPA complex to 2300 mg/L. read-across

Shuhaimi (2012): Freshwater snails Melanoides tuberculate were exposed to nominal 10, 32, 56, 87, 100 mg/L MnSO₄under static conditions for 96h. The LC50 value for 48 and 96h was determined to be 120.43 mg Mn²⁺/L and 45.56 mg Mn²⁺/L, respectively. read-across

Research of the QSAR-Toolbox databases: Glycine was reported to be readily biodegradable as proved by a database entry generated from a study conducted according to OECD 301. QSAR predictions: EpiSuite, SciQSAR and Leadscope revealed a very low toxicity to aquatic invertebrates with the following EC50 values: EpiSuite:32749.543 mg/L; SciQSAR:1788.819 mg/L; Leadscope: 610.1076 mg/L. read-across

 

Toxicity to aquatic algae and cyanobacteria:

- the cell growth of Nitzschia closterium in the presence of different metal ion concentrations (Rosko and Rachlin, 1975). The medium in which the algae were incubated was either chelating or non-chelating. The algae were incubated with different concentrations of dissolved 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. 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 measuring 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 MnCl₂in five concentration of dissolved MnCl₂for 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.

Additional information

Aquatic invertebrates:

There are no data for manganese monoglycinate sulfate regarding short term toxicity to aquatic invertebrates. However, the ecotoxicity of manganese monoglycinate sulfate was assessed based on a read-across approach. This read-across hypothesis is based on transformation of the target and source substances to common compounds (scenario1 of the RAAF). The target substance manganese monoglycinate sulfate and the source substances manganese sulfate, manganese Chloride, and other manganese compounds are ionic and consist of the Mn²⁺cation and the respective anion (glycine). For a more detailed explanation of the read-across hypothesis please refer to the general justification for read-across in section 13 of the IUCLID file.

Data are available for several Mn²⁺salts as well as for glycine.

In the study of Biesinger and Christensen (1972) water flea (Daphnia magna) were exposed to concentrations of 5 and 10 mg/L MnCl₂for 48 h under static conditions. The LC50 was determined to be 9.8 mg Mn²⁺/L.

In another study of Martin and Holdich (1985) the toxicity of metal ions towards crustaceans was determined in Asellus aquaticus and Crangonyx pseudogracilils after 48h and 96h under static conditions. At least eight Mn²⁺concentrations (from dissolved MnCl₂) were used in this test. The 48h LC50 was determined as follows: 1389 ppm for Crangonyx pseudogracilils and the 96h LC50 was 694 ppm for Crangonyx pseudogracilils.

In the study of Sorvani and Sillanpää the 24h LC50 of free divalent manganese ions and the respective EDTA/DTPA complex were determined in Daphnia magna. After 24h the EC50 value was 56 mg/L for the free ions and increased for the respective EDTA complex (940 mg/L) and for the DTPA complex to 2300 mg/L.

In the study of Shuhaimi (2012) freshwater snails Melanoides tuberculate were exposed to nominal 10, 32, 56, 87, 100 mg/L dissolved MnSO₄under static conditions for 96h. The LC50 value for 48 and 96h was determined to be 120.43 mg Mn²⁺/L and 45.56 mg Mn²⁺/L, respectively.

The other source substance glycine is also considered to be of very low toxicity to aquatic life based on its utilization in aquatic invertebrates and plants. This assumption is substantiated by a research of the QSAR-Toolbox databases. Glycine was reported to be readily biodegradable as proved by a database entry generated from a study conducted according to OECD 301. Furthermore, QSAR predictions performed with EpiSuite and the commercial software programs SciQSAR and Leadscope revealed a very low toxicity to aquatic invertebrates.

Based on the varying organisms that were used in the different studies and the different endpoints that were investigated, i.e. LC50 vs. EC50 values, the EC50 value for aquatic invertebrates was set to 56 mg Mn²⁺/L (which corresponds to 230 mg manganese monoglycinate sulfate) for precautionary reasons.

In the study of Sorvani and Sillanpää the 24h LC50 value of the source substance MnSO₄was determined in the recommended test organism Daphnia magna. The methods used were sufficiently described to judge this study as reliable. In the study of Biesinger and Christensen (1972) only two concentrations of MnCl₂were tested. Martin and Holdich (1985) used invertebrates that are not explicitly recommended for ecotoxicity testing. Furthermore, the results obtained from this study revealed higher LC50 values as compared to the other studies, thus Asellus aquaticus and Crangonyx pseudogracilils are less sensitive to metal toxicants. Similarly, the freshwater snail Melanoides tuberculate seems to be less sensitive to metal ions after 48h exposure, whereas after 96h exposure the LC50 value was in a similar range as the EC50 value for Daphnia magna. The other source substance glycine is an abundant occurring amino acid and can be found in virtually every living organism. It is generally accepted that glycine exhibits only a very low toxicity. The request of the QSAR-Toolbox databases and several reliable QSAR calculations substantiate this notion. Thus, in the target substance manganese monoglycinate sulfate the contained manganese is expected to be the main toxicant. Based on the provided results and the read-across hypothesis the EC50 value for aquatic invertebrates is set to 56 mg Mn²⁺/L, corresponding to 230 mg manganese monoglycinate sulfate/L.

 

Aquatic algae and cyanobacteria:

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.

 

For a detailed justification for read-across please refer to the attached document in Chapter 13.