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Administrative data

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:
PNEC aqua (freshwater)
PNEC value:
6.87 µg/L
Assessment factor:
10
Extrapolation method:
assessment factor
PNEC freshwater (intermittent releases):
30.1 µg/L

Marine water

Hazard assessment conclusion:
PNEC aqua (marine water)
PNEC value:
0.687 µg/L
Assessment factor:
100
Extrapolation method:
assessment factor
PNEC marine water (intermittent releases):
3.01 µg/L

STP

Hazard assessment conclusion:
PNEC STP
PNEC value:
5.28 mg/L
Assessment factor:
10
Extrapolation method:
assessment factor

Sediment (freshwater)

Hazard assessment conclusion:
no hazard identified

Sediment (marine water)

Hazard assessment conclusion:
no hazard identified

Hazard for air

Air

Hazard assessment conclusion:
no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:
no hazard identified

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:
no potential for bioaccumulation

Additional information

Conclusion on classification

Aluminium is the major constituent of "Neutralisation and reduction products of bauxite residue from refinement process" which is released in the transformation/dissolution (T/D) test (OECD Series on Testing and Assessment No 29, see IUCLID section 4.8) and is hence relevant for the environmental hazard and risk assessment. The Al compounds occurring in "Neutralisation and reduction products of bauxite residue from refinement process" (i.e. Al(OH)3 and Al(OH)O) are assumed to be the source of Al released in the transformation/dissolution test. Therefore, the classification of "Neutralisation and reduction products of bauxite residue from refinement process" is focused on Aluminium ions and evaluation strategy is based on read-across from existing Aluminium ecotoxicological studies. 

As demonstrated in the T/D test, a loading rate of 100 mg substance/L at pH 8 results in a dissolved concentration of ca. 0.36 mg Al/L and 0.48 mg Al/L after 7 and 28 days, respectively.

 

Classification for acute aquatic hazards

The most sensitive species in acute aquatic tests is fish with a 96-h LC50 of 0.57 mg Al/L, corresponding to a 96-h LC50 of 3.01 mg "Neutralisation and reduction products of bauxite residue from refinement process"/L. As the most sensitive acute effect value is > 1 mg/L, a classification for acute aquatic hazards is not warranted.

 

Classification for chronic aquatic hazards

The most conservative chronic no-observed effect concentration (NOEC) of aluminium ions (Al3+) is 13 µg/L (0.013 mg/L) for fish reproduction. Back-calculated based on the estimated molecular weight range of "Neutralisation and reduction products of bauxite residue from refinement process" of ca. 142.48 – 254.91 g/mol, this results in a substance-based worst-case NOEC of 0.069 mg/L. Aluminium release from "Neutralisation and reduction products of bauxite residue from refinement process" may lead to dissolved Al3 + concentrations of up to 0.5 mg Al/L for 100 mg /L substance loading.  Aluminium, as an element, cannot be further degraded hence needs to be considered as not rapidly degradable.

Based on the ECHA Guidance on the application of the CLP criteria (see https://echa.europa.eu/documents/10162/2324906/clp_en.pdf/58b5dc6d-ac2a-4910-9702-e9e1f5051cc5), Appendix IV, chapter IV.5.3.2.2, the poorly soluble substance "Neutralisation and reduction products of bauxite residue from refinement process" is classified into category Chronic 4, as the dissolved Al ion concentration obtained from the 7 day transformation test at the high loading rate (100 mg/l) of 0.36 mg/L is lower than the acute ERV of 0.57 mg AL/L and there is no evidence of rapid environmental transformation and no bioaccumulation.