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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

A study was performed to determine the toxicity of various soluble (AlCl3, Al2(SO4)3, Al(NO3)3) aluminium salts and one poorly soluble (Al2O3) aluminium oxide to the ciliated protozoon Tetrahymena pyriformis. The inhibitory concentrations (IC50) were determined to be 15 µg/ml (AlCl3), 10 µg/ml (Al2(SO4)3), 14 µg/ml (Al(NO3)3) and 495 µg/ml (Al2O3), in terms of aluminium, respectively.
Any effects of ammonia on microorganisms is considered to be irrelevant because ammonia is a component of the natural nitrogen cycle and is produced by the degradation processes in sewage treatment plants.

Key value for chemical safety assessment

EC50 for microorganisms:
10 mg/L

Additional information

Toxicity of aluminium nitride to aquatic invertebrates can be elicited by aluminium ions and/or ammonia (NH3) released from the material during hydrolysis under aqueous conditions. Ammonia can be expected to be intrinsically non-hazardous to microorganisms at concentrations potentially generated by aluminium nitride. The assessment of the hazardous properties of AlN is thus conducted in basis of the intrinsic properties of aluminium ions:

A study was performed to determine the toxicity of various soluble (AlCl3, Al2(SO4)3, Al(NO3)3) aluminium salts and one poorly soluble (Al2O3) aluminium oxide towards microorganisms.

The ciliated protozoon T. pyriformis, strain GL (TP), was grown under axenic conditions, without shaking, in the proteose-peptone yeast substrate defined medium (PPYS) supplemented with inorganic salts. The cultures were incubated at 28 °C in capped 500 ml Fernbach flasks containing 100 ml of PPYS medium. For the bioassays the cell density was adjusted to 1.0E+04 cells/mL and cells were used in the exponential growth phase. Aliquots of one millilitre were immediately (t0) withdrawn from the control (untreated) and the treated cultures, then every hour for 9 h. The samples were fixed with 1 ml of 4 % formaldehyde in Isoton® buffer and the cell number was determined by counting with an electronic cell counter.

The inhibitory concentration (IC50) was determined to:

- aluminium chloride: IC50= 15 µg/ml

- aluminium sulphate: IC50= 10 µg/ml

- aluminium nitrate: IC50= 14 µg ml

- aluminium oxide: IC50= 495 µg/ml