Hydrogen (glycinato-N,O)[sulphato(2-)-O,O']ferrate(1-)

Endpoint summary

Description of key information

Short-term toxicity to aquatic invertebrates:

- study conducted similar to OECD guideline 202 (Lilius et al., 1995), Daphnia magna were exposed to different concentrations of dissolved FeSO4 under static conditions for 24h, EC50 = 45.6 mg/L Fe2 +; Read-across

- study conducted with mayflies exposed to diferent metal ions at concentrations of 0, 10, 50,100, 250 and 500 mg/L at pH 4.5 and pH 7 for 120 h, measurement of survival and escape reaction, LC50 for pH 7 at 96h incubation: 89.5 mg/L and at 120h: 106.3 mg/L ; Read-across

- study conducted similar to OECD 202 (Martin and Holdrich, 1986), Asellus aquaticus and Crangonyx pseudogracilils were either incubated with different metal ions in different concentrations. Crangonyx pseudogracilils was exposed to eight concentrations of dissolved FeSO4 under static conditions for 96h, 96h LC50: 95 mg/L Fe2 +; Read-across

- QSAR prediction performed with ECOSAR for glycine, 48h LC50 for invertebrates based on mortality was determined, LC50: 32749.54 mg/L ; Read-across

- supporting study (Shuhaimi et al., 2012) in snails (M. tuberculata), were exposed to differing concentrations of ferric chloride (Fe3 +) under static conditions for four days, parameter observed: mortality, 48h LC50: 21.78 mg/L, 96h LC50: 8.49 mg/L ; Read-across

- supporting study (Sorvani and Sillanpää, 1996) in Daphnia magna similar to OECD guideline 202, Dapnids were exposed to Fe3+ either in chelating or non-chelating medium for 24h, 24h EC50 for Fe3 +: 16 mg/L ; Read-across

Toxicity to aquatic algae and cyanobacteria:

- study conducted with three strains of green microalgae (Subramaniyam, 2016), namely Chlorella sp. MM3, Chlamydomonas sp. MM7 and Chlorococcum sp. MM11, the algae were exposed to 0, 5, 10, 15, 20, 25, 50 mg/L Fe (from dissolved FeSO4) nominal for 96h under static conditions, EC50 for the three strains were 9.47, 9.05, and 8.49 mg/L Fe+2, respectively. Read-across

- study conducted with Chlorella vulgaris (DoorenDeJong, 1965), Chlorella vulgaris was cultivated with FeCl3 in the following concentrations: 0, 0,0001, 0.0002, 0.0003, 0.0005, 0.001, 0.002, 0.003, 0.005, 0.0075, 0.01, 0.02, 0.03, 0.05, 0.075, 0.1, 0.25, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 7, 8, 9, 10, 20, 24, and 30% (w/v) in mineral medium for 4 month, the 4 week EC0 was determined at 0.003g/L corresponding to 3 mg/L Fe3 +. Read-across

- QSAR estimation performed with ECOSAR for glycine, two EC50 values were reported, one for the class aliphatic amines: 93748.5 mg/L and one for neutral organics: 144000 mg/L based on growth rate. Read-across

Additional information

No information on aquatic toxicity are available for ferrous glycinate sulfate. However, based on the information available for the single constituents, namely glycine and Fe2 +, i.e. FeSO4, and the read-across hypothesis described in Chapter 13, that metal ions chelated with amino acids are not more toxic than the metal ions alone, the LC50 for aquatic invertebrates was determined from the study of Lilius et al., 1995 for the following reasons. The data available were obtained from studies using different model organisms of which Daphnia magna appeared to be the most sensitive species. Furthermore, the studies were conducted with differing durations and with two oxidations states of iron, namely Fe2+ and Fe3 +. It is generally accepted that Fe3+ is the more toxic species and due to the occurrence of Fe2+ in the target substance ferrous monoglycinate sulfate, Fe2+ represents the toxicity determining species in the target substance., Thus, comparison of the detected LC50/EC50 values of the available publications is not possible. Therefore, based on the data available, the study of Lilius et al., 1995 is considered to represent the most reliable LC50 for Fe2+ ions in Daphnia magna and is used as a worst case assumption for further assessment of the environmental risk.

There are no data available for the target substance ferrous monoglycinate sulfate regarding the toxicity to aquatic algae and cyanobacteria. However, based on the read-across hypothesis that the target substance dissociates into its constituents, namely Fe2 +, SO42 - and glycine, when it is dissolved in aqueous solutions or is at least enzymatically hydrolysed by the organism, data for the respective constituent was evaluated to determine the aquatic toxicity of the target substance ferrous monoglycinate sulfate.

In the study of Subramaniyam, 2016, three different algae species were exposed to 0, 5, 10, 15, 20, 25, 50 mg/L Fe (from dissolved FeSO4) nominal for 96h under static conditions, EC50 for the three strains were 9.47, 9.05, and 8.49 mg/L Fe2+, respectively. In another study conducted with Chlorella vulgaris (DoorenDeJong, 1965) the algae were exposed to 0, 0,0001, 0.0002, 0.0003, 0.0005, 0.001, 0.002, 0.003, 0.005, 0.0075, 0.01, 0.02, 0.03, 0.05, 0.075, 0.1, 0.25, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 7, 8, 9, 10, 20, 24, and 30% (w/v)dissolved FeCl3 in mineral medium for 4 month, the EC0 for Fe3+ was 3 mg/L.

In order to predict the effects of glycine towards aquatic algae a QSAR estimation was preformed with ECOSAR and revealed an EC50 value of 93748.5 mg/L for aliphatic amines and 144000 mg/L for neutral organics.

Since glycine is an ubiquitously occurring substance which is known to readily metabolised and serves as energy substrate in the intermediary metabolism its toxicity towards aquatic organisms is also considered to be low. Hence, the toxicity of the target substance ferrous monoglycinate sulfate is expected to be determined by Fe2 +. Fe3+ is known to react with other anions and form salts with a low water solubility, thus, its toxicity towards aquatic organisms as reported in the study of DoorenDeJong (1965) which also was conducted over 4 months, a duration which is far above the timeframe recommended by the respective OECD guideline, the EC0 value obtained from this study is only used as supporting information. The EC50 value obtained from the study of Subramaniyam, 2016, is considered as the most relaible value for the estimation of the toxicity of the target substance because the conduction of the study was appropriate to determine an EC50 value with a suitable duration (96h) and under conditions which are similar to that recommended by the OECD guideline 201. The most sensitive algae species appeared to be Chlorococcum sp. with an EC50 value of 8.49 mg Fe2 +/L which corresponds to 45.9 mg ferrous monoglycinate sulfate/L.