Trisodium hexafluoroaluminate

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:

8.7 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

30.5 mg/kg sediment dw

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

3.05 mg/kg sediment dw

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

6.02 mg/kg soil dw

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

Reliable acute ecotoxicity test results are available for fish, invertebrates and algae. The 96-h LC50 in Brachydanio rerio is 99 mg/L from a GLP compliant OECD guideline study (Solvay, 2008a). An OECD guideline study is available for short-term toxicity in invertebrates, the 48-h EC50 in Daphnia magna is 156 mg/L (IWL, 1998). The 72-h ErC50 is 8.8 mg/L in the freshwater algae Pseudokirchneriella subcapitata (tested as Selenastrum capricornutum), the 72-h NOEC for growth rate is 1.0 mg/L from a GLP compliant OECD guideline study (Solvay, 2008b).

Long-term ecotoxicity tests with fish and invertebrates are not available.

A GLP compliant respiration inhibition test (OECD 209) is available, the 3-h EC50 is >160 mg/L in activated sludge in a (Solvay, 2008c).

Studies with sediment and terrestrial organisms for cryolite are not available. Due to the dissolution of cryolite in water, it is expected, that risk assessment of water compartment covers the realistic worst case situation also for sediment.

For cryolite exposure via soil (uptake from soil matrix), no data are available. However, it should be noted, that due to the dissolution behaviour, it can be expected, that when cryolite is mixed to soil matrix and gets in contact with pore water, it is dissolved to different aluminum and fluoride species and no exposure to dissolved cryolite itself occurs in soil.

Based on the information of U.S. EPA (1996), cryolite is applied in dust and in suspended form where much of cryolite can expected to remain in particulate form. Ingestion of cryolite is expected to be the relevant route of exposure. The substance is considered to act predominantly as stomach poison while it releases fluoride ions (U.S. EPA, 1996). Fluoride ions in turn form complexes with metal containing enzymes in stomach (Corbett et al., 1974). The available two studies on the target organisms beet armyworm (Spondoptera exigua; Yee and Toscano, 1998) and tobacco caterpillar (Spodoptera litura; Prasad et al., 2000) provide evidence on that ingestion as route of exposure and particulate form as form ofexposure in combination cause increased response to increased dose.

Two other studies with honeybee (Apis mellifera; Atkins and Kellum, 1986) and blueberry flea beetle larvae (Altica Sylvia;Forsythe and Collins, 1994) could be used in a tentative manner for PNEC derivation related to exposure similar to insecticidal application. The honeybee brood LD50 of 224.5 g cryolite/m2 is related to the application rate as well as the results with the blueberry flea beetle larvae (LD50 ≤1.67 g cryolite/m2). Target species blueberry flea beetle (short term field test) seemed to be more sensitive than honeybee brood. Despite of the uncertainty regarding to whether a proper dose-response resulted in the test with blueberry flea beetle larvae, the lower application rate of 1.67 g/m2 from this study is considered as the critical acute effect value.

Furthermore, the lowest NOEC-value at 7 months exposure to HF of highly sensitive plants species of 0.2 µg/m3 will be taken into consideration for the assessment of the atmospheric compartment.

Data are not available to assess the toxicity of cryolite to birds. However, there is a large mammalian dataset available. Furthermore, due to the dissolution of cryolite, it is expected, that no secondary poisoning occurs but exposure caused by cryolite is covered by the PNECoral for fluoride.

Conclusion on classification

Reliable acute ecotoxicity test results are available for fish (96-h LC50 is 99 mg/L), Daphnia magna (48-h EC50 is 156 mg/L) and algae. The lowest acute aquatic toxicity value is a 72-h ErC50 of 8.8 mg/L for the freshwater algae Pseudokirchneriella subcapitata (tested as: Selenastrum capricornutum). In the same species, the 72-h NOErC is 1.0 mg/L. Long-term tests with fish and aquatic invertebrates are not available. As inorganic compound, cryolite is not biodegraded but abiotic dissociation and subsequent interactions occur instead. At present, cryolite is included in Annex I of Directive 67/548/EEC with a classification N; R51-53 for the environment (Toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment). According to the EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008, cryolite is classified as Aquatic Chronic Cat.2; H411 (Toxic to aquatic life with long lasting effects).

 

The PBT and vPvB criteria of Annex XIII to the REACH Regulation (EC) No 1907/2006 do not apply to inorganic substances. Therefore a PBT/vPvB assessment was not performed.