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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

NOEC (3h) ≥1000mg/L, (nominal), read across

Key value for chemical safety assessment

EC50 for microorganisms:
1 000 mg/L
EC10 or NOEC for microorganisms:
1 000 mg/L

Additional information

Experimental on the toxicity of aluminium dihydrogen triphosphate to microorganisms are not available. Therefore read across from the comparable substance aluminium orthophosphate (CAS 7784-30-7) was deemed acceptable for assessment. Both substances are inorganic orthophosphates containing a phosphate anion and an aluminium cation.

The phosphate anion (PO43 -) is ubiquitous in natural waters and is an essential micronutrient for many organisms. Orthophosphates are not anticipated with direct acute or long-term adverse effects on aqueous or terrestrial organisms. Therefore the toxicity of the above substances will be predominantly determined by the presence of the Al3+cation. On this basis the ASRI study was conducted on aluminium orthophosphate. This approach is considered to be reliable and justified and no further testing for aluminium dihydrogen triphosphate is required.

A study was performed to assess the effect of aluminium orthophosphate on the respiration of activated sewage sludge. The method followed that described in the OECD Guidelines for Testing of Chemicals (1984) No 209, Method C.11 of Commission Regulation (EC) No. 440/2008 and US EPA Draft Ecological Effects Test Guidelines OPPTS 850.6800. Activated sewage sludge was exposed to an aqueous dispersion of the test item at concentrations of 10, 32, 100, 320 and 1000 mg/L for a period of 3 hours at a temperature of 21 ± 1°C with the addition of a synthetic sewage as a respiratory substrate. The rate of respiration was determined after 3 hours contact and compared to data for the control and a reference item, 3,5-dichlorophenol. The effect of the test item on the respiration of activated sewage sludge gave a 3-Hour EC50of greater than 1000 mg/L. The No Observed Effect Concentration (NOEC) after 3 hours exposure was ≥1000mg/L.