Reaction mass of Limestone and calcium fluoride and calcium sulfate

Endpoint summary

Description of key information

The substance is a reaction mass of calcium fluoride and calcium sulfate and calcium carbonate. The typical composition of the reaction mass is: ca. 47.5 % CaF₂, ca. 22.3 % CaSO₄ and ca. 12.1 % CaCO₃.  No studies are available on the substance itself, instead the assesment of the hazard of the substance was performed based on data available for the 3 constituents as weight of evidence approach. Data from the respective REACH registration dossiers of CaF₂, CaSO₄ and CaCO₃ has been used as a basis. Calcium fluoride is the main constituent of the substance (47.5%) and its hazard value has been used as worst case. Regarding the 2 others constituents of the substance, calcium sulfate and calcium carbonate, they are extremely common in all natural surface waters and are therefore ubiquitous in the environment.

 

Acute toxicity to fish

Short-term toxicity to fish has been evaluated for calcium sulfate and calcium carbonate. As expected, no hazards have been identified for both constituents.

As no reliable studies are available for calcium fluoride, fish acute toxicity data published on NaF have been used. The chosen key value was the lowest reported LC50 among all reliable evaluated studies. The reported value by Janssen et al. (1989) on Oncorhynchus mykiss, 96h exposure (EU RAR and ICD) was 51 mg F-/ L, which translates to 104.7 mg CaF2/L. Note that this value is above water solubility of CaF2 being 15 mg/L at 25°C. No reliable information is available on marine water fish.

 

On the basis of the available LC50 for CaF2, the LC50 value for the reaction mass can be concluded: 209.4 mg RM/L. This value is calculated by taking into account that the reaction mass contains only 50% of CaF2 (ca. 47.5 w/w % CaF2) and that the additional of Ca2+ through CaSO4 and CaCO3 would even further reduce the toxicity of CaF2 as free F- will be complexed.

 

It can be concluded that no toxicity of the reaction mass of calcium fluoride, calcium sulfate and calcium carbonate is expected on aquatic fish at short term.

 

Long-term toxicity to fish

Calcium sulfate and calcium carbonate, are ubiquitous in the environment and essential to living organims : no long-term studies are available and no hazards are expected for both constituents.

No studies are available for calcium fluoride. Available studies on NaF were used as read-across source. The chosen key value was the lowest reported NOEC, among the available studies, in a 29 days test J- check 2010 study with NaF and Oryzias latipes. The LOEC and NOEC are ≥ 9.9 mg/L NaF (the highest test concentration) which related to >9.2 mg/L CaF2.

On the basis of the available NOEC for CaF2, the NOEC value for the reaction mass can be concluded: > 18.4 mg RM/L. This value is calculated by taking into account that the reaction mass contains only 50% of CaF2 (ca. 47.5 w/w % CaF2) and that the additional of Ca2+ through CaSO4 and CaCO3 would even further reduce the toxicity of CaF2 as free F- will be complexed.

Short-term toxicity to aquatic invertebrates

No short-term toxicity has been observed for CaSO4 and CaCO3.

No studies are available for calcium fluoride. Available studies on NaF were used as read-across source in a weight-of-evidence approach. The chosen key value for freshwater invertebrated was the lowest reported EC50 among all the evaluated studies reported by Pearcy et al. 2015 on Hyalella azteca after 96h exposure to NaF. The EC50 was 24.8 mg/L F- which converts in 50.94 mg/L CaF2. Effects to marine invertebrates (Mysidopsis bahia) have been reported with an EC50 of 21.6 mg/L CaF2 (EU RAR). 

On the basis of the available EC50 for CaF2, the EC50 value for the reaction mass can be concluded: 101.88 mg RM/L for freshwater invertebrates and 43.2 mg/L for marine invertebrates. This value is calculated by taking into account that the reaction mass contains only 50% of CaF2 (ca. 47.5 w/w % CaF2) and that the additional of Ca2+ through CaSO4 and CaCO3 would even further reduce the toxicity of CaF2 as free F- will be complexed.

 

Long-term toxicity to aquatic invertebrates

Calcium sulfate and calcium carbonate, are ubiquitous in the environment and essential to living organims: no long-term studies are available and no hazards are expected for both constituents.

As no studies are available for calcium fluoride, available studies on NaF have been used instead. The chosen key value was the lowest reported NOECs among all the evaluated studies reported in EU RAR 2001 on a 21d study on Daphnia magna. Observed NOEC was 3.7 mg/L F-, which converts in 7.6 mg/L CaF2.

 

On the basis of the available NOEC for CaF2, the NOEC value for the reaction mass can be concluded: 15.2 mg RM/L. This value is calculated by taking into account that the reaction mass contains only 50% of CaF2 (ca. 47.5 w/w % CaF2) and that the additional of Ca2+ through CaSO4 and CaCO3 would even further reduce the toxicity of CaF2 as free F- will be complexed.

 

Toxicity to aquatic algae and cyanobacteria

Calcium sulfate and calcium carbonate, are ubiquitous in the environment and essential to living organims: no hazards have been identified for both constituents  in the available studies.

As no studies are available for calcium fluoride, studies on NaF were used as read-across source. The chosen key values were the lowest reported as EC50 for short term studies (up to 96 h) and NOECs for long term studies (up to 21 days). The values were drawn for the EU RAR 2001 review, which summaries different studies on a wide range of marine and freshwater algae. The lowest EC50 value among the freshwater algae was 43 mg/L F- for Scenedesmus sp, which converts to 88.32 mg/L CaF2. The lowest EC50 value among the marine algae was 81 mg/L F- for Skeletonema costatum, which converts to 166.37 mg/L CaF2. The lowest NOEC value among the freshwater and marine algae was 50 mg/L F-, which converts to 102.7 mg/L CaF2.

 

On the basis of the available effect levels for CaF2, the values for the reaction mass can be concluded: 

EC50 freshwater algae: 176.64 mg/L RM

EC50 marine water algae: 332.74 mg/L RM

NOEC for fresh and marine water algae: 205.4 mg/L RM

 

These values are calculated by taking into account that the reaction mass contains only 50% of CaF2 (ca. 47.5 w/w % CaF2) and that the additional of Ca2+ through CaSO4 and CaCO3 would even further reduce the toxicity of CaF2 as free F- will be complexed.

 

Toxicity to microorganisms

Studies show that calcium sulfate and calcium carbonate, ubiquitous in the environment and essential to living organims, are not toxic to sewage sludge microorganisms.

In the EU RAR 2001 review, the long-term NOEC-values for micro-organisms range from 7.1 to 510 mg/l. Only the test with 3 h exposure of activated sludge was performed according to international accepted guidelines, yieling an EC10 of 510 mg/L F-. In this test the given EC10-value for respiration inhibition is considered to be an equivalent for a NOEC. Using the molecular weight, this results in a NOEC of 1047.51 mg/L CaF2.

 

On the basis of the available effect levels for CaF2, the values for the reaction mass can be concluded: 2095 mg/L RM. These values are calculated by taking into account that the reaction mass contains only 50% of CaF2 (ca. 47.5 w/w % CaF2) and that the additional of Ca2+ through CaSO4 and CaCO3 would even further reduce the toxicity of CaF2 as free F- will be complexed.