Aluminium sodium tetrahydroxide

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

14 µg/L

Assessment factor:

10

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

4.3 µg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

1.4 µg/L

Assessment factor:

100

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

10 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

no data available: testing technically not feasible

Sediment (marine water)

Hazard assessment conclusion:

no data available: testing technically not feasible

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

no data available: testing technically not feasible

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

The examination of the PNEC values must be carried out with caution due to complexity of aluminium specification in the environment. This applies to the aquatic toxicity values, since it is well known and supported by numerous investigations that the insolubility of aluminium species under environmental condition delimits the bioavailability of aluminium for organisms in the environment. Under the standard ecotoxicological test conditions, it is difficult to maintain the speciation of aluminium during the test unchanged and to exclude the physical effects that result from adsorption. Hence, LC/EC50 values as well as NOEC values available demonstrate the variability of toxic effects of aluminium under different test conditions, but not a clear hazard profile of aluminium. In addtion, , the toxic effects derived from dissolved aluminium at lower pH represent the worst-case scenario for aluminum released into aquatic compartment. Hence, toxicity data for aluminium and PNEC derivation may be expressed in terms of concentrations of dissolved aluminium at pH 6 or in terms of dissolved aluminium at pH 8, which clearly overestimate the toxicity effect of sodium aluminate itself. Therefore, the derived PNECs would not be suitable for a refined risk assessment.

Conclusion on classification

Classification for acute aquatic toxicity is based on the most sensitive species / the lowest test result obtained for dissolved aluminium tested as Al(OH)₃, which is the main decomposition product of sodium aluminate in water: The acute algae toxicity test revealed no toxicity up to 4 µg/L dissolved aluminium. Based on the available studies, this value is considered to be the lowest test concentration, which refers to dissolved Al. The transformation/dissolution study indicated that up to 4 µg/L aluminium may be released from Al(OH)₃at pH 6 and 8 respectively. Hence no acute toxicity was determined up to the water solubility for Al(OH)₃. The BCF determined in fish were215, 123, and 36 at pH 5.3, 6.1, and 7.2, respectively,indicating a low potential for bioaccumulation for aluminium (BCF < 500). Therefore, no classification needs to be assigned for sodium aluminate according to EC 1272/2008 (CLP).

The assessment criteria for the justification of a bioaccumulation potential according to 67/548/EEC is BCF not exceeding 100. Thus, at low pH in aquatic environment aluminium is categorised as moderate accumulated according the DSD criteria. However, data on elimination rate in brook trout show that aluminium is eliminated from the fish tissue more rapidly at pH 5.3 than pH 6.1 and 7.2, respectively.Furthermore,it is well established that the initial uptake of aluminium by fish essentially takes place on the gill mucous layer. It has been suggested that the rate of transfer of aluminium into the fish body is either slow or negligible under natural environmental conditions (Spry and Wiener 1991). Hence, the elevated Al concentration at low pH conditions is regarded predominantly as adsorption phenomena. Aluminium is not considered to bioaccumulate to a significant degree. Therefore, no classification needs to be assigned for sodium aluminate according to 67/548/EEC (DSD).

 

In conclusion, sodium aluminate is not classified as hazardous to the aquatic environment according both to 67/548/EEC and Regulation (EC) 1272/2008 (self Classification).