Potassium tetrafluoroaluminate

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

0.005 mg/L

Assessment factor:

1 000

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

0.048 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0 mg/L

Assessment factor:

10 000

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

0.36 mg/L

Assessment factor:

100

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

0.729 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

0.073 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

0.143 mg/kg soil dw

Extrapolation method:

equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

PNEC water:

Fluoride may enter the environment from both natural (volcanoes, weathering of minerals and marine aerosols) and anthropogenic sources. The latter include the use of production and use of potassium tetrafluoroaluminate. The concentration of fluoride in natural waters depends on the geological, physical and chemical characteristics at the location. In surface waters that are influenced by F-containing rock formation the natural F-concentration is considerably higher. Water of small rivers in the highlands of (e.g.) contained up to 4.7 mg/L (Geochemischer Atlas, 1985). High fluoride levels (>20 mg/L) are also reported in natural waters from other European communities (WHO, 1984). The median F-concentration in measured from 2000 to 2008 in several Dutch rivers is 0.2 mg/L (www.waterbase.nl). In seawater, F-concentrations are higher than in freshwater with an average of 1.4 mg/L (Slooff et al., 1988). The substantial variation in background levels throughout means that a PNEC derived from standard tests is not directly applicable to regions with high natural F-levels. Therefore the background concentration is added to the derived PNEC based on fluoride (PNEC freshwater, added and PNEC marine water, added). The median concentration in Dutch rivers is taken as the background level for freshwater. For marine water values from Slooff et al. (1988) are taken into account.

PNEC soil:

The mean fluoride concentration in mineral soil is 200 to 300 mg/kg; whereas that of organic soils is generally lower (97 mg/kg). In the fluoride concentrations in clay soils range from 80 to 700 mg/kg dw. In soils with higher pH values a higher amount of soluble F-complexes is found (Slooffet al. 1988). Because the variation in background levels throughoutis substantial, the Dutch reference value is used as the PNEC soil (the reference value is the environmental quality standard at which the soil is considered “clean” and can fulfill all possible functions (VROM, 2000)).

Conclusion on classification

As inorganic compound, potassium tetrafluoroaluminate is not biodegraded but abiotic dissociation and subsequent interactions occur instead. Nonetheless, for classification purposes, inorganic substances are to be considered as non-rapidly degradable. Ecotoxicity data for three trophic levels (fish, invertebrates and alga) are available from the structural analogue multiconstituent aluminium potassium fluoride. From these data a critical effect value for classification of >10 mg/L was derived (fish 96h-LC50). Correction for the molecular weight of potassium tetrafluoroaluminate lowers the critical effect value to >8.9 mg/L, therewith passing the >10 mg/L cut-off value for classification as aquatic chronic category 2 (H412) and thus leading to a more stringent classification than its structural analogue. However, in the fish study at the maximum tested concentration of 10 mg/L no mortality and no signs of abnormal behaviour were reported. Therefore, the more stringent classification is considered not to be in proportion to the slight decrease of the critical effect value due to recalculation for molecular weight. Based on these considerations, and in line with the classification of its structural analogue multiconstituent aluminium potassium fluoride, potassium tetrafluoroaluminate is classified as chronic to the environmental category 3; H412 (Harmful to aquatic life with long lasting effects) according to the EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008. For the same reasons, the substance is classified as R52 -53 (Harmful to aquatic organisms, may cause long-term adverse effects in the aquatic environment) according to Directive 67/548/EEC.