Triiron bis(orthophosphate)

Endpoint summary

Additional information

Data on the aquatic toxicity of Triiron bis(orthophosphate) (CAS 14940-41-1) are not available. In accordance with Annex XI, 1.5, of Regulation (EC) No 1907/2006, the read-across approach to the structurally related substances Iron II Sulfate Heptahydrate (CAS 7782-63-0) was applied to fulfil the standard information requirements. The Article 13 (1) of Regulation (EC) No 1907/2006 states that "information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI are met.” In particular for aquatic toxicity, information shall be generated whenever possible by means other than vertebrate animal tests, which includes the use of information from structurally related substances (grouping or read-across).

According to ECHA Guidance on information requirements and chemical safety assessment, Chapter R.6: QSAR and grouping of chemicals (p. 117), the hypothesis is that properties of the target and source substances are likely to be similar as a result of the presence of a common metal ion, or ion complex including a hydrated metal ion, and following from this have a similar chemical behaviour. Due to the structural similarities and consistent trend in physico-chemical and ecotoxicological behaviour, the selected source substances are considered suitable to read-across to Triiron bis(orthophosphate) (CAS 14940-41-1). The main assumption is that the specific metal-containing compound to be evaluated shows the same hazards as the most water-soluble compounds. Further information on the read across substances is given in the read-across justification in chapter 13 of the IUCLID file.

Data matrix: ecotoxicological properties

ID	Substance name	Short-term toxicity to fish	Long-term toxicity to fish	Short-term toxicity to Daphnia magna,	Long-term toxicity to Daphnia magna	Short-term toxicity to algae	Toxicity to microorganisms, 3h EC50 [mg/L]
Target CAS 14940-41-1	Triiron bis(orthophosphate)	RA CAS 7782-63-0	Annex VIII	RA CAS 7782-63-0	RA CAS 7782-63-0	RA CAS 7782-63-0	Waiving
Source 1 CAS 7782-63-0	Iron II Sulfate Heptahydrate	Experimental result: LC50 (96h) ≥ 100 mg/L (nominal)	--	Experimental result: EC50 (48h) = 91 mg/L (nominal)	Experimental result: NOEC (21 d): 10 mg/L (nominal)	Experimental result: EC50 (72 h) = 150 mg/L (nominal); NOEC (72 h) = 100 mg/L (nominal)	Experimental result: NOEC (3 h) ≥1000mg/L,

 

Aquatic toxicity and microorganisms

Experimental results on the acute aquatic toxicity of Triiron bis(orthophosphate) (CAS 14940-41-1) are not available. The assessment is deviated based on aquatic toxicity studies conducted with the read-across substance Iron II Sulfate Heptahydrate (CAS 7782-63-0).

The acute toxicity of Iron II Sulfate Heptahydrate (CAS 7782-63-0) to fish was investigated in two studies. One study (Moe, 2002) on the acute toxicity of the substance to Gold Medaka (Oryzias latipes) was conducted according to OECD 203 under semi-static conditions. There were no effects on survival observed at the test substance concentration (LC50 (96h) ≥ 100 mg/L nominal; LC50 (96h) ≥ 66.9 mg/L time-weighted mean). The second study on the acute toxicity of the substance to Gold Medaka (Oryzias latipes) was conducted according to JIS K0102-1998-71 (MOE, 2002). After 96 hours a LC50 > 45.2mg/L was determined.

The acute toxicity of the read across substance Iron II Sulfate Heptahydrate (CAS 7782-63-0) to Daphnia magna was determined in a study following OECD 202. After an exposure period of 48 hours an EC50 = 91 mg/L (nominal) (MOE, 2002).

One study for toxicity to algae is available for the read across substance Iron II Sulfate Heptahydrate (CAS 7782-63-0). This static study (MOE, 2002) was conducted according to OECD 201 with Pseudokirchneriella subcapitata. At test termination after 72 hours an EC50 = 150 mg/L (nominal) and a NOEC = 100 mg/L (nominal) were determined.

Experimental data on the long-term toxicity of Triiron bis(orthophosphate) (CAS 14940-41-1) to aquatic organisms are not available. The assessment is therefore based on a long-term toxicity study conducted with the source substance Iron II Sulfate Heptahydrate (CAS 7782-63-0). This semi-static study (MOE, 2002) was conducted according to OECD 211. After 21 days exposure period a NOEC of 10 mg/L based on reproduction was determined.

Experimental data on the toxicity of Triiron bis(orthophosphate) (CAS 14940-41-1) to microorganisms are not available. Besides soluble aluminium compounds ferrous sulphate is one of the most common coagulant used in wastewater treatment plant for removing of phosphate. A toxic potential to aquatic microorganism and at the application doses ranged from 50 to 1000 mg/L (Gebbie, 2006) is not expected.

Based on the available information the target substance Triiron bis(orthophosphate) (CAS 14940-41-1) is considered not acutely or chronically toxic to aquatic organisms at levels up to the limit of water solubility of 1.5 mg/L under environmental conditions.

Reference:

Gebbie P. (2006) AN OPERATOR’S GUIDE TO WATER TREATMENT COAGULANTS, 31st Annual Water Industry Workshop – Operations Skills Page No 14. University Central Queensland Campus – Rockhampton, 4 to 6 July, 2006.