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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

No studies are available for reaction mass of calcium fluoride, calcium sulfate and calcium carbonate; however, aquatic bioaccumulation is not expected to occur as available information on the constituents of the reaction mass do not indicte a potential for bioaccumulation. 

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Additional information

Reaction mass of calcium fluoride, calcium sulfate and calcium carbonate is an inorganic substance. Its main constituent (CaF2) has a low water solubility. Calcium fluoride will dissociate to some extent (as determined by the limit of solubility) in the aqueous environment and dissociate to form calcium and fluoride ions, both of which are environmentally ubiquitous. Calcium is also ubiquitous in living species, and is taken up normally from the environment and is therefore not considered further. Fluoride is also taken up from the environment and typically accumulates in plant species, and in the skeleton or exoskeleton of animal species. Fluoride also adsorbs strongly to sediment and is transformed to other mineral species. The bioaccumulation potential of fluoride from the substance will therefore be limited by its low water solubility and its tendency to adsorb to sediment.

The second constituent, calcium sulfate, dissociates into the calcium Ca2+ and sulfate SO42- ions at environmental pH. These are essential to all living organisms (flora and fauna) and their intracellular and extra-cellular concentrations are actively regulated. Aquatic or sediment bioaccumulation is therefore not expected.

the third constituent is calcium carbonate, an inorganic ionic solid, for which an octanol/water partition coefficient cannot be reliably determined. Calcium carbonate dissociates into the calcium Ca2+and carbonate CO32-ions at environmental pH. These are essential to all living organisms (flora and fauna) and their intracellular and extra-cellular concentrations are actively regulated. Bioaccumulation is therefore not expected. Recent research has shown that calcium carbonate is naturally produced as an excretory product by marine teleosts. These fish continuously drink seawater to avoid dehydration. This exposes them to an excess of ingested calcium, which they precipitate into calcium carbonate crystals in the gut. The fish then excrete these unwanted chalky solids, sometimes called 'gut rocks', in a process that is separate from digestion and production of faeces. Other Phylla also produce calcium carbonate in significant quantities: Mollusc shells and certain algae coccoliths (Coccolithophores) are primarily composed of calcium carbonate.