Strontium fluoride

Endpoint summary

Additional information

Acute toxicity:

Acute toxicity data for fluoride (F) are available for several aquatic freshwater species covering three trophic levels (primary producers, primary and secondary consumers) and aquatic microorganisms. Furthermore, data on several aquatic saltwater species, covering two trophic levels (primary producers and secondary consumers) is available. The tables below provide an overview of the effect values for acute freshwater and saltwater toxicity of fluoride.

The freshwater algae Scenedesmus sp. was identified as the most sensitive species (96 h EC50 43.0 mg F/L, EU RAR 2001).

 

Furthermore, a 20-h NOEC value for growth inhibition of microorganism of 7.1 mg F/L (not specified) was observed (EU RAR 2001).

In recent studies, additional species representing other taxonomic groups, including aquatic plants and gastropds were tested. The lower LC/EC50 values should be viewed with caution since the corresponding tests were conducted at non-standard conditions. Chloride appears to act as a major modifying factor for fluoride toxicity. However, at standard conditions, recent data confirm that fluoride is acutely toxic to freshwater organisms.

 

The saltwater organism Mysidopsis bahia was identified as the most sensitive species with a 96 h EC50 value of 10.5 (nominal) mg F/L (EU RAR 2001).

 

Finally, it is concluded that fluoride is acutely toxic to freshwater organisms, such as algae and aquatic microorganisms.

 

Table: Overview of acute aquatic toxicity data of F in freshwater:

Species	Taxonomic group	Parameter	Endpoint	Value (mg F/L)	Reference
Oncorhynchus mykiss	fish	mortality	96 h LC50	51.0 (measured)	EU RAR 2001
Daphnia magna	crustacea	mortality	48 h EC50	97 (nominal)	EU RAR 2001
Scenedesmus sp.	algae	biomass	96 h EC50	43.0 (nominal)	EU RAR 2001
Oncorhynchus mykiss	fish	mortality	96 h LC50	10.4 - 150 (measured)*	Pearcy et al. 2015
Hyalella azteca	crustacea	mortality	96 h LC50	8.1 - 50.9 (measured)*	Pearcy et al. 2015
Potamopyrgus antipodarum	gastropoda	mortality	96 h LC50	58.5 (measured)	Alonso & Carmargo 2011
Lemna minor	plant	growth	7 d IC50	391 (measured)	Pearcy et al. 2015
Pseudokirchneriella subcapitata	algae	growth	72 h IC50	273 (measured)	Pearcy et al. 2015

* at different hardness, alkalinity, chloride concentrations

Table: Overview of acute aquatic toxicity data of F in saltwater:

Species	Parameter	Endpoint	Value (mg F/L)	Reference
Mysidopsis bahia	not specified	96 h EC50	10.5 (nominal)	EU RAR 2001
Skeletonema costatum	biomass	96 h EC50	81.0 (nominal)	EU RAR 2001

 

 

Chronic toxicity:

Chronic toxicity data for fluoride (F) are available for several aquatic freshwater species covering three trophic levels(primary producers, primary and secondary consumers) and for one saltwater organism.The table below provides an overview of the effect values for chronic toxicity of F.

 

Freshwater fish with Onchorhynchus mykiss were identified as the most sensitive species, regarding a 21 d NOEC of 4.0 mg F/L (measured, EU RAR 2011).

 

The lowest saltwater algae 21 d NOEC value amounted to 50 mg F/L (nominal, EU RAR 2001).

In recent studies, additional species representing other taxonomic groups, including aquatic plants, insects and gastropds were tested. The lower IC10 values should be viewed with caution since the corresponding tests were conducted at non-standard conditions. Chloride appears to act as a major modifying factor for fluoride toxicity. However, at standard conditions, recent data confirm that fluoride is moderately toxic to freshwater organisms.

 

In conclusion, F is chronically toxic to freshwater organisms and has a low chronic toxicity potential to saltwater algae. 

 

Table: Overview of chronic aquatic toxicity data of F in freshwater:

Species	Taxonomic group	Parameter	Endpoint	Value (mg F/L)	Reference
Oncorhynchus mykiss	fish	mortality	21 d NOEC	4.0 (measured)	EU RAR 2001
Daphnia magna	crustacea	reproduction	21 d NOEC	8.9 (arithmetic mean)	EU RAR 2001
various freshwater algae	algae	biomass	7 d NOEC	50 (nominal)	EU RAR 2001
Uronema parduczi	algae	growth inhibition	20 h NOEC	7.1 (not specified)	EU RAR 2001
Salvelinusnamaycush	fish	embryo viability	17 d IC10	>134 (measured)	Pearcy et al. 2015
Pimephales promelas	fish	growth	7 d IC10	14.6 – 77.7 (measured)*	Peary et al. 2015
Oncorhynchus mykiss	fish	Growth & survival	7 d IC10	5.8 – 21.6 (measured)*	Peary et al. 2015
Potamopyrgus antipodarum	gastropoda	growth	28 d NOEC	4.6 (measured)	Alonso & Carmargo 2011
Ceriodaphnia dubia	crustacea	Reproduction & survival	7 d IC10	8.0 – 12.5 (measured)*	Pearcy et al. 2015
Hyalella azteca	crustacea	Growth & survival	14 d IC10	1.8 - 5.2 (measured)*	Pearcy et al. 2015
Chironomus dilutus	Insecta	Growth & survival	10 d IC20	8.2 (measured)	Pearcy et al. 2015
Lemna minor	plant	growth	7 d IC10	125 (measured)	Pearcy et al. 2015
Pseudokirchneriella subcapitata	algae	growth	72 h IC10	192 (measured)	Pearcy et al. 2015

  * at different hardness, alkalinity, chloride concentrations

Table: Overview of chronic aquatic toxicity data of F in saltwater:

Species	Parameter	Endpoint	Value (mg F/L)	Reference
various saltwater algae	biomass	21 d NOEC	50 (nominal)	EU RAR 2001