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Ecotoxicological information

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Experimental data on the acute and chronic aquatic toxicity of dicalcium pyrophosphate are not available. In accordance with Annex XI, 1.5, of Regulation (EC) No 1907/2006, read-across to the structurally related substances tricalcium bis(orthophosphate) (CAS 7758-87-4), calcium hydrogenorthophosphate (CAS 7757-93-9) and calcium bis(dihydrogenorthophosphate) (CAS 7758-23-8) was conducted to fulfil the standard information requirements. In accordance with Article 13 (1) of Regulation (EC) No 1907/2006, "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 Annex XI, Item 1.5, of Regulation (EC) No 1907/2006 substances can be considered to be similar if their physicochemical, toxicological and ecotoxicological properties are likely to be similar or follow a regular pattern as a result of structural similarity. The target and the source substances are calcium phosphates. All substances are characterised by comparable physico-chemical properties. They are inorganic solids and thus not volatile. Though the water solubility of the target and source substances varies, a comparable environmental fate and ecotoxicological profile is anticipated for the substances.

Acute toxicity studies on tricalcium bis(orthophosphate) (CAS 7758-87-4) are available for three trophic levels (fish, Daphnia, algae). All studies were conducted according to the internationally accepted OECD guidelines. The determined E(L)C50 values were >100 mg/L for fish, Daphnia and algae. Toxic or other adverse effects were not observed for any of the tested species.

Chronic toxicity data are not available. Long-term toxicity of the substance is not anticipated due to the absence of acute toxicity and the fact that calcium and phosphate are essential micronutrients for aquatic organisms.

A study on the toxicity to aquatic microorganisms is available for the target substance calcium bis(dihydrogenorthophosphate) (CAS 7758-23-8). The study was conducted according to OECD guideline 209. Adverse effects on aquatic microorganisms were not observed. An EC50(3h)> 1000 mg/L based on the nominal test substance concentrations was determined.

Based on the available data dicalcium pyrophosphate is considered not toxic to aquatic organisms.