Hexacalcium hexaoxotris[sulphato(2-)]dialuminate(12-)

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

6.8 µg/L

Assessment factor:

1 000

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

68 µg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.68 µg/L

Assessment factor:

10 000

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

61.3 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

The registered substance is Aluminium calcium oxide sulfate (Ettringite (anhydrous)): CAS number 12004 -14 -7. So far Ettringite (anhydrous) does not exist physically. Only the hydrous form Ettringite is the existing substance (CAS number 12252-12-9 (Ettringite (Ca₆Al₂[(OH)₁₂/(SO₄)₃]^.26 H₂O). It is a naturally occuring mineral but it is also produced by inorganic synthesis. Its an inorganic cristalline substance and according to its sum formula existing of

Al³⁺, Ca²⁺, OH^-und SO₄^2--Ions. The final allocation of the ions in a crystalline structure depends strongly on the pH: only in a very alkaline environment a crystallographic homogenous structure is formed: Ettringite. Due to its chemical nature Ettringite is not stable under natural environmental conditions of neutral pH. The main degradation products are calcium sulfate (dihydrate) with limited solubility resulting in free calcium and sulfate ions and insoluble aluminium hydroxides and insoluble aluminium oxides (at neutral pH range). Under these conditions the solubility of aluminium hydroxides/ aluminium oxides is very low and results in precipitation in an amorphous form. Only gypsum (CaSO₄^.2H₂O) is to some extent soluble at neutral pH.

Conclusion on classification

Classification according to Regulation (EC) No 1272/2008 (CLP) and Directive 67/548/EEC and subsequent regulations

- No classification needed: the data are conclusive but not sufficient for classification.

1. aquatic toxicity:

short term: lowest EC50: 1 - 10 mg/L (Daphnids)

chronic: EC10 (Algae): EC10 = 2.3 mg/l

2. Potential for or actual bioaccumulation: none

3. Degradation (biotic or abiotic) for organic chemicals: Ettringite is inorganic. However, Ettringite or for the aquatic environment relevant Aluminium precipitates in form of Aluminiumhydroxides and can thus be considered rapidly removable. (See also CLP-Guidance (Ch. IV.3)).

Thus, Ettringite is not hazardous to the aquatic environment.