Ammonium fluoride

Toxicity to aquatic algae and cyanobacteria

Description of key information

A number of short-term studies are summarised and reviewed in the EU RAR and Dutch ICD of sodium fluoride.  The EC50 values for freshwater algae are reported to range from 43 to 122 mg/L (as fluoride ion, F-). For marine algae the EC50 was 81 mg/L in a single study with Skeletonema costatum. In long-term studies, NOEC values of 50 -249 mg/L and 50 -200 mg/L are reported for freshwater and marine algae, respectively.

Key value for chemical safety assessment

EC50 for freshwater algae:

43 mg/L

EC50 for marine water algae:

81 mg/L

EC10 or NOEC for freshwater algae:

50 mg/L

EC10 or NOEC for marine water algae:

26 mg/L

Additional information

As ammonium fluoride decomposes in an aqueous environment into ammonium and fluoride ions, toxicity of these two ions has been studied and the most conservative one has been kept for assessment.

Regarding ammonium toxicity, one key study Bentic diatoms from field (Eems Dollard estuary) is available for ammonium chloride. Tests were conducted in saltwater during 10 days, with 10 different species.

For most of them NOEC-10d was 26 mg/L as NH₄Cl.

For fluoride, the EU RAR reviews and summarises the available data on the short-term toxicity of sodium fluoride to freshwater and marine algae species. The EC50 values for freshwater algae are reported to range from 43 to 122 mg/L (as fluoride ion, F^-). For marine algae the EC50 was 81 mg/L in a single study with Skeletonema costatum.

In long-term studies, NOEC values of 50 - 249 mg/L and 50 - 200 mg/L are reported for freshwater and marine algae, respectively.

In conclusion, considering the respective toxicity to marine and freshwater algae/cyanobateria, the most conservative NOEC for fluoride in freshwater is retained as key data for hazard assessment in both compartments. In marine environment, the most conservative data from ammonium chloride is retained for hazard assessment.